The Science of Ice Cream by Chris Clarke

The Science of Ice Cream by Chris Clarke

This was actually the first book I bought on ice cream. Before any recipe books even! Why? Well, there’s loads of ice cream recipes on the internet. But not so much in depth stuff about how it works scientifically.

And if you want to get serious about making ice cream. If you want to tweak your recipes with confidence. If you want to be able to fix problems. Then you need to understand at least a little bit about the science of ice cream.

Chris Clarkes book is certainly not the only book on the science of ice cream. And it’s probably not the best. But it’s definitely the cheapest!

Because for some reason the other books are really expensive. “Ice Cream” by Goff and Hartel is usually around $100. And “Tharp and Young on Ice Cream”, by (you guessed it) Tharp and Young is often over $200.

I wasn’t prepared to pay that much when I was starting out, so as Chris Clarkes book was around $30, he got my money!

I wanted something that was going to explain in pretty simple terms how all the ingredients came together to make ice cream.

And this book does that pretty well. There’s no colour on the pages. And there are more diagrams than photos. So it’s not an especially visually stimulating read.

Diagrams in The Science of Ice Cream by Chris Clarke

But Clarke is a genuine “ice cream scientist” and does a pretty good job of making a complicated subject “readable by 16-18 year olds”.

It’s primarily aimed at undergraduate food science students and people that work in the ice cream industry. But Clarke has tried to make it accessible to anyone that has studied science to A level (which I think are the same as APs in the United States?).

As someone who hasn’t studied science for a long, long time and knew nothing about ice cream science before picking the book up, I found some of it a bit hard going. There is some complicated stuff here.

But it also explains the basics well. And you can always come back to the more detailed bits as your knowledge and experience increases.

As you’d expect from someone who works in the industry there is a quite a lot about the industrial production of ice cream that won’t be of interest to people making ice cream at home or even small scale artisan producers.

But I found found enough here to interest me, I found large parts of it easy enough to understand and I’ve come back to use it as a reference several times as I’ve questioned stuff I’ve been reading elsewhere.

In fact a large part of my ice cream science page was based around the information I learned in this book.

So what exactly is in the book?

Contents of The Science of Ice Cream by Chris Clarke

In Chapter 1 he briefly covers the history of ice cream and the current state of the global market. But this is very brief.

In Chapter 2 he explains what colloidal dispersions are (small particles of one thing in another thing), how liquids freeze, and what rheology is (the study of the way liquids flow). All in relation to ice cream.

In Chapter 3 he introduces the basic ice cream ingredients including proteins, different types of sugars, oils and fats, water, emulsifiers, stabilizers and a few common flavors. But this is very much an introduction…

Stabilizers in The Science of Ice Cream by Chris Clarke

Those looking for an in-depth analysis of which stabilizers work best together will be disappointed.

Chapter 4 is about making ice cream in the factory. And it’s very much from a commercial angle. So there’s nothing about the sort of ice cream makers we use at home. But the science and the processes are the same. So it covers mix preparation, homogenization and pasteurization, ageing, freezing and hardening.

Chapter 5 is about different ice cream products like cones, bars and sandwiches and how they are assembled in an ice cream factory. Not much of interest here. For me at least!

In Chapter 6 Clarke explains how the structure of ice cream is measured. There’s some pretty heavy stuff here involving microscopic measurements and complicated equations which was well over my head. But at the end there’s some interesting bits on how me measure the sensory qualities of ice cream.

Chapter 7 is all about how ice cream is a complex composite material, with all the different elements in perfect balance. There’s some great stuff here about the four components (ice crystals, liquid matrix, fat and air), how they work together and what each contributes to ice cream.

And then in Chapter 8 there’s a a load of experiments for the students to do with ice cream. Presumably to prove the scientific principles explained in the rest of the book.

Back cover of The Science of Ice Cream by Chris Clarke

So, there’s no recipes for salted caramel gelato in this book! It’s pure science. It has a quite commercial, industrial perspective. And there could be more on the sort of science that a home enthusiast will find useful.

But I think it’s a good, cheap introduction to the concepts. And while it won’t fill in all the gaps, if you pick it up knowing very little about how ice cream comes together scientifically, you’ll come out the other side with a much firmer grasp of whats going on beyond the scoop!

Making gelato at home: How to keep it soft

Why do we love gelato? Yes it seems more exotic. But there are certain qualities that we just don’t get with other ice creams…

The lower fat content gives it a cleaner taste that delivers flavor faster, more intensely and with less aftertaste. And the warmer serving temperature gives it that soft, slightly elastic texture that feels so luxurious.

But unfortunately, the qualities that make Italian gelato so delicious also make it very difficult to create at home. Or at least to keep at home. It’s actually easy enough to make. But keeping it in decent condition for any length of time is really tricky.

Why? Well, the lower fat content and the higher serving temperature are linked. Fat doesn’t freeze. This means that higher fat ice creams will remain soft and scoopable at low temperatures. While gelato tends to freeze into a icy brick.

And that’s why gelato is served at higher temperatures. Usually between 10 and 22 ° F (-12 to -6  ° C). This means it can have that clean low fat taste while still remaining soft and pliable.

The problem we have when trying re-create gelato at home is that our freezers are usually set to around 0 ° F (-18 ° C). And this is far too cold for gelato. Left in a freezer at this temperature it will become hard and icy after just three to four hours.

Sure, you can leave it out of the freezer for a while to soften. But it will tend to melt around the edges rather than soften uniformly. And when it goes back in the freezer, the melted ice cream re-freezes creating bigger ice crystals and further compromising the texture. No good at all.

So what can we do? We can’t increase the butterfat content because then it won’t be gelato! And we can’t usually adjust the temperatures of our freezers up to 10 ° F (-12 ° C). But we can adjust the sugar content of the gelato…

As we know, sugar not only imparts sweetness to ice cream. It also contributes to its softness by reducing the freezing point of the water in the mixture. So if we increase the amount of sugar in the recipe, we’ll also increase the amount of liquid that isn’t frozen, which will keep the ice cream softer.

But most ice cream is already far too sweet for my taste. And more sugar will obviously make it sweeter! So rather than using more table sugar (sucrose), we can use dextrose which is only 70% as sweet as sucrose and depresses the freezing point of water by almost twice as much. So we win twice!

Now I’m really lucky in that I can adjust the temperature of my freezer between 5 and -9 ° F (-15 and -23  ° C). And I thought I’d have a go making a gelato that has it’s optimal texture at 5 ° F (-15 C).

The recipe I’ve been using so far is great if you eat it all after an hour or so of hardening in the freezer. But if you leave it any longer, it’s ruined. By making it optimal at 5 ° F (-15 C), I should have a larger window to eat it in!

I’m not expecting it to last for weeks. But it would be nice to get a couple of days out of before there is a noticeable degradation in quality.

So anyway, I played about with the existing recipe to lower the freezing point by replacing a lot of the sugar with dextrose.

I was a bit worried that my ice cream maker wouldn’t be able to freeze the mixture at all now and that I’d end up with a sloppy mess. So I added Skimmed Milk Powder (SMP) to soak up some of the liquid and I also added some corn syrup for more body…

346 g Milk
94 g Cream
25 g Skimmed Milk Powder
24 g Table Sugar
60 g Dextrose
48 g Corn Syrup
3 g Locust Bean Gum

The problem was that to maintain the same final weight (600 g) and butterfat content (7%), the amount of milk (and therefore water) was reduced significantly. And this meant that the 3 g of Locust Bean Gum had a much stronger effect…

Once aged overnight, the mixture was really gelatinous. And you could still feel that gelatinous texture in the final ice cream if you let it melt slowly in your mouth. However, it firmed up really well in the machine, froze really well in my freezer and was probably optimal after 4 hours.

Apart from the slightly gelatinous texture though, it was thick, creamy and really nice.

The next day it was definitely a little to hard, but it was still much softer and had a far superior texture to my previous recipe. So encouraged, I tweaked some more…

363 g Milk
92 g Cream
17 g Skimmed Milk Powder
84 g Dextrose
42 g Corn Syrup
1.8 g Locust Bean Gum

Here, I essentially dropped the Locust Bean Gum from 0.5% to 0.3% to try to get rid of the gel like texture. And I got rid of the table sugar altogether and bumped up the dextrose to further lower the freezing point.

And it was a disaster. It took much longer to firm up in the machine. It was thin, watery and cold. And it was also slightly grainy!

I suspect the graininess was from the increased dextrose content. If there’s too much dextrose in a mix, as the water freezes, the level of dextrose in the remaining water will rise beyond it’s solubility limit and small crystals of the sugar will start to form. These small crystals are detectable as sandy or grainy texture on the tongue.

So I tweaked again. Bumping the Locust Bean Gum up to 0.4% and putting the tweaking the sugar again…

363 g Milk
96 g Cream
25 g Skimmed Milk Powder
24 g Table Sugar
60 g Dextrose
60 g Corn Syrup
2.4 g Locust Bean Gum

This was really soft coming out of the machine. I don’t think I’d get away with being any softer. And after putting it in the freezer I had to go out and didn’t get back for another 6 hours. When I did it was frozen solid and pretty much ruined.

So basically its back to the drawing board. At the moment I’m not sure its actually possible to make gelato at home that will stay in reasonable condition if left in the freezer all day. Even if the freezer will go down to 5 ° F (-15 C). 🙁

Glossary

Agar Agar
A stabilizer. Comes from seaweed. Often used as a vegetarian alternative to gelatin.

Ageing
Occurs when we leave the ice cream mixture in the fridge for around 6 hours. During this time the fat globules shed their coating of milk proteins and develop spiky needles. This makes it easier for them to clump together to form the structures that support the air bubbles when we start to churn it.

Air
Gives ice cream its softness. Ice creams with more air seem fluffy. Ice creams with less air seem more creamy. The amount of air in an ice cream is measured by something called “overrun”. It can vary between 20 and 100%.

Batch Freezer
This is just what the professionals call their ice cream machines! It churns and freezes the base mixture into ice cream.

Blast Freezer
This is a a very powerful freezer that the professionals use to chill the churned ice cream very quickly to the desired storage temperature. The faster it’s frozen in the blast freezer, the less chance of ice crystal growth.

Butterfat
Is the proper name for the fat in milk and cream.

Carrageenan
A stabilizer. Extracted from Irish Moss seaweed. There’s three different types: Kappa, Iota, and Lambda each offering different properties.

Cream
This the source of most of the fat in ice cream. The proportion of fat in cream can vary between 12% and 55%. I tend to use 32%, just because it’s the easiest to get hold of.

Dextrose
A sugar. 70% as sweet as table sugar (sucrose). But lowers the freezing point of water by nearly twice as much. So it’s useful when you want softer, less sweet ice cream.

Emulsifiers
Encourage the fat globules in the milk and cream to cluster together to form the long strands that support the air bubbles. Lecithin, found in egg yolks is the most common traditional emulsifier. Commercial ice cream often uses the synthetic Polysorbate 80.

Extraction
Where the churned ice cream is removed from the machine (and usually moved to the freezer). You should try to keep the extraction time as short as possible to reduce the chances of melting and subsequent ice crystal growth.

Gelato
An Italian ice cream. Usually contains less fat, less air and is served at warmer temperatures than other ice creams.

Guar Gum
A stabilizer. Comes from the milled seeds of the Guar plant which is a type of bean. Suppresses ice crystal development. Also thickens and adds body to the ice cream. In higher concentrations it will make the ice cream elastic and chewy.

Hardening
When we remove the mixture from the ice cream maker it usually has the consistency of soft serve and will melt very quickly. So we put in the freezer to harden for a certain amount of time.

Hydrocolloids
The scientific name for stabilizers. Hydrocolloids are simply tiny insoluble particles of a substance dispersed in water. They form a network that restricts the flow of water to increase viscosity (thickness).

Ice
Gives ice cream its hardness and body. Around 30% of ice cream is made up ice crystals. For smooth ice cream, we want to keep those ice crystals as small as possible.

Lactose
A sugar. Found naturally in milk. It contributes very little to sweetness or freezing point suppression. Too much Skimmed Milk Powder in the mix can raise the levels Lactose beyond its solubility limit so that it forms small crystals that give the ice cream a sandy or grainy texture.

Locust Bean Gum (LBG)
A stabilizer. Comes from the seeds of the Carob tree. One of the most effective suppressors of ice crystals. And will also thicken the mixture. Usually needs to be heated to high temperatures (up to 85 °C / 185 °F) to get the best out of it.

Maltodextrin
A sugar. Not very sweet at all. And has very little affect on freezing point. Great for soaking up liquid and adding bulk to ice cream.

Milk
Contributes water, protein and some fat to the ice cream. Important for that distinctive dairy taste.

Milk Solids Non Fat (MSNF)
All the solids that aren’t fat in the milk! So that’s the proteins, the lactose and various minerals. MSNF make up between 6 and 11% of ice cream. You can increase the proportion of MSNF in a mix either by reduction through heating or by adding Skimmed Milk Powder.

Partial Coalescence
Occurs during churning. This is where the fat globules in the milk start to clump together to form long strings that support the air bubbles in the final ice cream. Can be encouraged by adding emulsifiers to the mix and ageing it in the fridge.

Pasteurization
Heating the mixture to kill harmful bacteria. With home made ice creams, this is important if you’re using eggs.

Skimmed Milk Powder (SMP)
Skimmed milk with all the water removed! Useful for adding protein and absorbing water. And will intensify the dairy flavors. Make sure you use spray dried SMP, as the barrel dried stuff can taste caramelized.

Stabilizers
Soak up water that might otherwise make the ice cream icy, coarse, thin or watery. They thicken the mixture, add body and smoothness to the ice cream and slow melt down. Popular stabilizers include egg yolks, cornstarch, Locust Bean Gum, Guar Gum.

Sorbet (Sorbetto)
Ice cream without any dairy. No milk. No cream. So sorbets contains more water and more sugar. Sorbetto is just Italian for sorbet.

Sugar
Sugar adds sweetness to ice cream. But it also keeps it soft by lowering the freezing point of the water in the ice cream. As more water freezes, the sugar in the remaining water becomes more concentrated. At some point the concentration will be so high that remaining water will not freeze. And it’s liquid solution that keeps the ice cream soft.

Water
Milk is 90% water. Cream is 60% water. It’s this water that freezes into the ice crystals that give ice cream it’s body. Too much unaccounted for water in the mix will result in thin, icy ice cream.

Xanthan Gum
A stabilizer. Comes from the fermentation of glucose, sucrose or lactose by the bacteria Xanthomonas campestris! It’s acid resistant so is good for fruit sorbets. And it also dissolves and works at any temperature. Be careful when using it with Locust Bean Gum as together they’ll form a gel.

Fior di Latte: A simple gelato recipe

Fior di latte is perhaps the simplest, purest ice cream of all. It’s a Sicilian gelato and fior di latte translates from Italian as “flower of milk”. Or “the best of the milk”.

And that’s all it is: a sweetened, milky ice cream. No eggs. No vanilla. Nothing but milk, cream and sugar.

I’ve seen it described as “monastically simple”. And while there is something quietly spiritual about those soft, white waves, there should be nothing austere about this gelato.

Thick, dense and creamy, as long as it’s not too sweet there’s a whole load of complex dairy flavors to explore here.

For many, a Fior di latte is the best test of a gelato shop. I suppose because any shortcuts an inferior gelateria might try to hide behind other flavors will be starkly apparent in their Fior di latte!

And that’s why it such a great place to start when you start learning to make ice cream. You can really concentrate on finding a balance of sweetness and creaminess and a texture and body that work for you.

I recommend making it again and again and again!

In this Fior di latte recipe I wanted to keep everything as simple as possible. So I’ve tried to keep the ingredients to a minimum and the preparation as straightforward as possible. Let’s have a look at each ingredient in more detail:

Milk

In this recipe I’m using 3.5% full fat milk. You could use semi-skimmed or even skimmed. But then you’d need to adjust the recipe.

This because when the milk is combined with the cream, we’re looking for a 7% total fat content. So if you use lower fat milk, you’ll need to use a higher proportion of cream.

Why 7%? Any less and it starts to taste a bit “hard” and “metallic” to me. And the sweetness is accentuated so it can start to taste like candy. Any more and the creaminess can leave a slightly cloying aftertaste.

Cream

Although it’s called Fior di latte, every recipe I’ve ever seen contains some amount of cream. And as I mention above, with too little cream it starts to taste a little “hard” to me.

There is in fact a variation called Fior di panna (“flower of cream”, obviously). But it’s not clear to me at what point the amount of cream means it’s a Fior di panna rather than a Fior di latte!

Anyway I’m using 36% fat cream. You can of course use cream with a different fat content. Just be aware that you won’t get the 7% fat that I’m aiming for without adjusting the recipe.

Table Sugar

Most ice cream tastes far too sweet to me. But we don’t use sugar just for the sweet taste. It also keeps the ice cream thick and soft and stops it getting icy. So we can’t just use less sugar when we want a less sweet ice cream.

What we can do, however is use different types of sugar. This is because different sugars have different levels of sweetness. So here we use a combination of table sugar (sucrose) and the less sweet dextrose.

Dextrose

Dextrose (also called Glucose) is only 3/4 as sweet as table sugar. So if we replace some table sugar with dextrose we still get all the structural benefits of sugar, but the ice cream will be less sweet.

Dextrose also reduces the freezing point of water more than table sugar, which means our ice cream will be softer too!

Locust Bean Gum

With no eggs to emulsify and stabilize this low fat gelato, we need to add something else to thicken the ice cream and stop it becoming icy and coarse.

Fior di latte gelato probably originates in Sicily and is essentially a frozen crema rinforzata which is a sweet milk pudding, thickened with cornstarch. And we could use cornstarch here.

But it’s a little bit more difficult to make Fior di latte with cornstarch. And more importantly, I’ve never managed to do it without being able to taste the cornstarch in the final gelato.

Locust Bean Gum works in the same way as cornstarch but is much more effective, much easier to use and most importantly: adds no discernible taste to the final gelato!

You probably won’t be able to find it in your local supermarket. But it’s widely available online, it lasts for ages and as we’ll see, a little goes a long way.

OK, the recipe…

Print Recipe
Fior di Latte Gelato
Prep Time 20 minutes
Cook Time 20 minutes
Passive Time 12 hours
Servings
servings
Ingredients
Prep Time 20 minutes
Cook Time 20 minutes
Passive Time 12 hours
Servings
servings
Ingredients
Instructions
Making the mixture
  1. Add the table sugar and the dextrose to a deep saucepan.
  2. Add the Locust Bean Gum to the saucepan. Unless you have specialized scales, it will be difficult to weigh 3 grams accurately. So, 3 grams is about the same as 1 ¼ compact teaspoons.
  3. Use a fork to thoroughly mix the dry ingredients. This part is really important. If the Locust Bean Gum isn't thoroughly mixed into the rest of the dry ingredients before you add the milk, it won't work properly.
  4. Add the milk to the saucepan and warm over a medium heat, stirring all the time to dissolve the dry ingredients.
  5. Keep stirring and checking the temperature with a digital cooking thermometer until the mixture reaches 185° F / 85° C.
  6. Remove from the heat and allow to cool to about 149° F / 65° C.
  7. Then add the cream and blitz for a couple of minutes with a hand blender.
  8. Transfer to a bowl and when the mixture stops steaming, cover with cling film and allow it to cool to room temperature.
  9. Put the bowl in the fridge until it the mixture cools to at least 45° F / 7° C. You'll get the best results if you leave it overnight.
  10. Place the container that you'll use to store the ice cream in the freezer. This will pre-chill it, so it's less likely to melt the ice cream when you're transferring it from the machine to the freezer.
Spinning the ice cream
  1. Remove the mixture from the fridge and give it another quick blitz with a hand blender.
  2. Turn on your ice cream maker and add the mixture.
  3. After around 20 minutes the mixture should have thickened up and have a texture like soft serve ice cream.
Freezing the ice cream
  1. As quickly as possible, transfer the mixture to the pre-chilled container and put it at the back of the freezer where it's coldest.
  2. After around 1 hour, the ice cream will have hardened up and be perfect for eating. It doesn't keep well though and will start to deteriorate after just one night in the freezer. So eat it quickly!
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  • Carl
  • November 1, 2016

Cuisinart ICE-30BC Pure Indulgence Ice Cream Maker Review

Cuisinart Ice-30BC Ice Cream Maker

The Cuisinart ICE-30BC Pure Indulgence is one of the most popular ice cream makers on the market. And there's some very good reasons for this...

It's well made, simple to use, easy to clean, completely dependable and most importantly: it makes great ice cream!

It's the first ice cream maker I ever used and I can't recommend it highly enough.

However, this type of machine does have very particular quirks and before you invest your money you should make sure that it suits your lifestyle and the way you want to make ice cream.

Cuisinart Ice-30BC Ice Cream Maker Boxed

So, please read this review where I'll look at how it works, I'll test it out with several different types of ice creams, gelatos, frozen yogurts and sorbets, I'll explore it's advantages and disadvantages and finally I'll recommend some alternatives in case this isn't quite the best machine for you...

How does the ICE-30BC work?

The ICE-30BC is a "removable bowl" machine. Not sure what this means? Well, domestic ice cream makers can generally be divided into three distinct types. And what makes each type distinct is the way they freeze the ice cream mixture:

  1. With ice and salt
  2. With a built in freezer
  3. ​With a removable bowl that's pre-chilled in your kitchen freezer

Machines like the ICE-30BC use a removable bowl that's lined with a special type of liquid gel. When the bowl is placed in a domestic freezer the gel hardens and freezes. Once it's removed from the freezer the gel keeps it's temperature really well so the bowl stays very cold for a long time.

Cuisinart Ice-30BC Ice Cream Maker Bowl Top

The ice cream mixture is then added to this bowl and the coldness is transferred from the bowl to the mixture as it's being churned.

And this is essentially how the ICE-30BC works. But let's look at this in a little more detail...

The ICE-30BC is an incredibly simple machine. And for me, this is a big advantage since it means there's very little to go wrong. There are just 4 separate parts: 

Cuisinart Ice-30BC Ice Cream Maker Parts
  1. the main body that contains the motor and an on/off switch
  2. a removable bowl
  3. a dasher that mixes the ice cream
  4. a tranparent lid

The main body of the ICE-30BC

The body of the ICE-30BC is made from an attractive, brushed stainless steel. It's easy to clean and looks smart and professional. On the front of the body is an embossed Cuisinart logo and manual on/off switch. Nothing else.

Underneath, there are four rubber tipped feet,​ which stop the machine slipping about as it churns. There's a 35" (90 cm) power cable that should be long enough for most domestic kitchens. And when not in use, the cable can be pushed up into a small gap in the base to keep everything nice and tidy!

Cuisinart Ice-30BC Ice Cream Maker Underneath

At the bottom of the cavity inside the body there's a 12 tooth gear that's turned by a motor in the base. This gear fits into a star shaped hole in the base of the removable bowl. So, as the gear turns: so does the bowl. (Yes, it's the bowl rather than paddle that turns, more on this later).

Cuisinart Ice-30BC Ice Cream Maker Gear

With this type of ice cream maker, it's important that the base is heavy and sturdy with a powerful motor. You want a machine that's stable as it churns and strong enough to keep turning as the mixture thickens.

And the ICE-30BC certainly does the job here.​ I've never had any problems with slipping gears or stalling motors. It's always proved more than capable of getting the job done. 

The ICE-30BC's removable bowl

​The removable bowl is thick and sturdy with a 2 quart (2 liter) capacity. It measures 7.8" (19.7 cm) across and 6.4" high (16.3 cm).

These measurements are really important. Because don't forget: before you can use the machine, the bowl needs to be pre-chilled in your freezer. If you can't fit the bowl in the freezer, you won't be able to make ice cream!

Cuisinart Ice-30BC Ice Cream Maker Bowl

So check you've got enough room in your freezer before you buy it! ​The bowl's not small. And this is one of the main disadvantages of these type of ice cream makers.

If you can find the room, great! If not, don't despair there are other options. There are machines with smaller bowls. Or there are machines with their own built in freezers.

As I mention above, the walls of the bowl are lined with a special liquid gel that hardens as it freezes. At room temperature, you can hear the gel sloshing about if you shake the bowl. But once it's frozen, it stops moving and this is one way you can tell it's been in the freezer for long enough.

Cuisinart Ice-30BC Ice Cream Maker Bowl Bottom

​Cuisinart recommend that you leave it in the freezer for at least 12 hours. I find that if I leave it in overnight I get the best results.

​This bowl is double insulated so it maintains it's temperature well. However, as soon as you remove it from the freezer it will start to warm up so it's important you use it straight away.

​The dasher of the ICE-30BC

​The dasher is the thing that actually mixes the ice cream mixture. It has 2 important jobs:

  1. To scrape frozen mixture off the sides of the bowl
  2. To add air to the mixture.​

The dasher that comes with the ICE-30BC is a simple piece of plastic. However it works really, really well. 

Cuisinart Ice-30BC Ice Cream Maker Bowl Dasher

With many other ice cream makers, the motor rotates the dasher in a stationary bowl. This can lead to problems as the ice cream mixture thickens and hardens. If the motor's weak it can struggle to turn the dasher. Sometimes it will slip or even stop rotating altogether. 

With the ICE-30BC (and indeed all Cuisinart's removable bowl machines), the motor rotates the bowl, while the dasher actually remains still, secured by the lid of the machine. So the dasher still passes through the mixture. But it's the bowl and the mixture inside it that are moving.

This approach seems to be much more efficient. Presumably it's due to the weight of the bowl, the stronger connection between it and the gear and the lower center of gravity? Whatever it is, it means the mixing works reliably well!

There is ​one negative point about the dasher though. One of it's jobs is to scrape frozen mixture from the sides of the bowl and redistribute the ice further into the mix. This is what cools the whole mixture down.

And the more ice it can scrape from the sides, the faster the whole mixture cools and the better the quality of the final ice cream. Unfortunately, in domestic machines the blade on the dasher never actually touches the side of the bowl: there's always a small gap.

With the ICE-30BC this gap is about 2 mm. N​ow I know that's no a lot! But it allows a 2 mm layer of frozen mixture to build up on the sides of the bowl. This layer insulates the rest of the mixture from the cooling sides of the bowl. Which means that the mixture takes longer to freeze so there's more time for unpleasantly large ice crystals to develop.

As I say, all domestic machines ​(at least all I've used), have this gap between the blade and the bowl. And it's not a big deal. (In fact with the ICE-30BC there's a way to avoid it which I explain in the next section). But it's worth noting as something which could be improved.

​The ICE-30BC's lid

The lid on the ICE-30BC is again a simple plastic thing. ​It's transparent which means you can always keep an eye on the progress of your mix. This is really important as different recipes and different quantities can take vastly different times to complete.

And while it might seem an obvious feature to include, with ice and salt machines its generally not possible and it's something I really miss.

Cuisinart Ice-30BC Ice Cream Maker Bowl Lid

There's also a big hole in the top of the lid. This serves 2 purposes. Firstly, it allows you to sample the mixture as it progresses. Believe me this impulse is almost impossible to resist!

And secondly, it allows you to add extra ingredients as the mixture thickens. Pieces of fruit, chocolate, cookies etc are best added towards the end of the process. And a lid with a hole means you can do this without having to stop the machine.

​As I mentioned above, the lid also serves to anchor the dasher. The top rim of the dasher slots into a special area of the lid as it's placed on the body. The dasher then catches against the lid as the bowl starts to turn.

Interestingly the lid does not fit snugly against to the body. There is around 1 cm play in either direction. It's clearly designed this way but it's not clear (to me at least) why!


How do we make ice cream with the ICE-30BC?

OK, so we've looked at the parts that make up the ICE-30BC. Now let's get down to business. Let's use it to make some ice cream and see how it does. There are 5 clear stages to making ice cream with the ICE-30BC:

  1. Make the mixture
  2. Freeze the bowl
  3. Freeze and churn the mixture in the ICE-30BC
  4. Transfer the mixture to the freezer to finish it off
  5. Cleaning the machine

Stage 1: Making the mixture

The ICE-30BC comes with it's own Cuisinart recipe booklet. This has almost 30 different recipes including simple Philadelphia style ice creams, French custards, Italian gelatos, frozen yogurts and even slushy drinks.

These recipes are specifically designed and tested to work with the ICE-30BC so they're a good place to start while you're finding your feet.

However, the best thing about owning your own ice cream maker is experimenting. Whether that's with recipes you find on the internet or your own inventions. That's where the real fun is!

Bear in mind though​: you can't just throw any combination of milk, cream and sugar into the machine and expect it to produce great results. You need to respect certain boundaries in terms of the proportions of different ingredients. And I talk about this a a lot in the science section.

So I can't stress this enough here: the biggest factor in whether your ice cream turns out good or bad is the recipe. So if things go wrong, the chances are it's the recipe rather than the machine. Obviously, some machines work better than others. And some machines might not work at all! But in that case it's usually a very specific and obvious fault.

​Each recipe is different. But there are certain things we can do with all recipes to make it easier for the ICE-30BC. And chief among them is to pre-chill the mixture.

This is good practice for any ice cream machine. But it's ​especially important for machines that use removable bowls, since the moment they leave the freezer they start to warm up.

There are some recipes ​that don't require heating. I'm thinking about Philadelphia style ice creams and certain egg-less gelatos here. And as long as the ingredients come straight from the fridge you can probably get away with putting them straight into the machine as soon as they're mixed.

But many recipes do require heating as they are mixed. And once they're finished they should be thoroughly chilled before they go anywhere near the ICE-30BC.

Ideally you'd cool the mixture as fast as possible and then leave it in the fridge overnight so it's around 4°C when you add it to the machine. Cooling it rapidly discourages harmful bacteria forming. And leaving it overnight has the added benefit of allowing the mixture to "age" which can improve the final product.

However, if you're in a rush you can transfer the mixture to a ziploc bag and then put the bag in an ice bath until it's cold enough to go in the machine. 

​In terms of quantities, the ICE30-BC comes with a 2 quart bowl. But you don't fill it with 2 quarts of mixture. This is because the machine adds air to the mixture so it obviously expands as it's churned.

In fact, to make sure it doesn't overflow the bowl, you probably shouldn't add more than 1.5 quarts of mixture. Certainly, all the recipes in the Cuisinart booklet produce more or less 1.5 quarts of mix.

So, find yourself a reliable recipe, mix up 1.5 quarts, thoroughly pre-chill to 4​°C and you're good to go...

Stage 2: Freezing the ICE-30BC's bowl

So we know we need to chill the bowl in the freezer. Preferably overnight. It's a good idea to cover the top of the bowl with a layer of cling film (secured with an elastic band) and put it in a plastic bag before you pop it in the freezer.

The cling film prevents any ice or vapor that might taint the ice cream getting in the bowl. And the plastic bag will protect the bowl from freezer burn.

As I talk about a lot elsewhere, the faster our mixture freezes, the better our final ice cream will be. And the colder we get the bowl, the faster it will freeze the mixture.

So first of all we want to get the freezer as cold as possible. Cuisinart recommend -17°C or lower. In fact, my freezer will go down to -23°C. So the night before I make ice cream, I set the temperature and put the bowl at the back of the freezer.

The back of the freezer is usually the coldest part. And by leaving it overnight we allow it to remain at a stable temperature, undisturbed by the opening and closing of the door that goes on in the daytime.

When I remove the bowl the next day the inside is at -22°C. But it starts warming up straightaway so we need to get moving...

Stage 3: Freezing and churning the mixture in the ICE-30BC

Before you add the mixture to the machine, it's a good idea to give it a blitz with a hand blender. This should remove any rogue lumps in the mix.

Then, remove the bowl from the freezer, add it, the dasher and the lid to the base and turn the switch on. The bowl will start to rotate while the dasher (anchored by the lid), remains still. Finally, pour the mixture in through the hole in the top of the lid.

​As I mention above, one flaw with this machine (and indeed all domestic ice cream makers) is that the blades of the dasher don't touch the side of the bowl. This allows an insulating film of ice to build up on the walls of the bowl which can slow the freezing process slightly. Which as we know is a bad thing!

However the great thing about this machine is that the hole in the lid allows you to put your hand inside and press the blades against the sides of the bowl!​ And as long as you do it right from the start and keep your hand in there for the duration, it will stop the unwanted layer of ice building up and the ice cream will finish faster!

How long will it take? Well, that depends on the recipe, the quantity of the mixture, how cold the freezer got the bowl and the ambient temperature in the room. So there's quite a lot of factors!

But usually it's between 15 and 40 minutes. I think the biggest factor here is the quantity of the mixture. I regularly have small batches of 600 ml finished in 15 minutes, even when the room is really warm 30°C.

One thing worth noting is that the ICE-30BC not quiet. In fact some people complain that it's unbearably loud! The sound it makes is sort of low grinding. But I don't think it's any louder than a hair drier and it's only on for a short time.   ​

​When it's ready the mixture has the smooth consistency of soft serve ice cream. Then, just switch off the machine, take off the lid, remove the paddle and scrape the ice cream into a pre-chilled storage container.

Stage 4: ​Transferring the ice cream from the ICE-30BC to the freezer

You can eat the ice cream straight from the machine. As I say, it's a bit like soft serve ice cream at this point. And it's perfectly lovely.

But it melts really quickly. And it benefits considerably from one, (preferably two) hours in the freezer where it will firm up to give a more resilient consistency.

Getting it into the freezer as quickly as possible without any melting will reduce the chances of ice crystal growth that might spoil the texture of the ice cream.

So, make sure you've got a container pre-chilling the freezer. The best ones are wide and shallow and made from steel since they will freeze the ice cream fastest.

The lid and the paddle of the ICE-30BC come out very easily and scraping the ice cream off the paddle and from the bowl is simple. So with some practice the you should be able to get a full batch out of the machine and into the freezer in seconds rather than minutes.

Covering the ice cream with a layer of cling film before you put the lid on the container will stop ice crystals forming on the surface of the mixture. Then put the container in the coldest part of your freezer, usually the back.

And that's pretty much it. All that's left to do is clean up while you wait for the ice cream to harden!

Stage 5: Cleaning the ICE-30BC

The ICE-30BC couldn't be easier to clean. The paddle and and lid can be washed in warm soapy water in a matter of seconds. I fill the removable bowl with warm water to melt any remaining mixture still frozen to the sides and then wash it in the same soapy water. The base usually needs nothing more than a quick wipe. Simple.


So what's the ice cream like?

This of course is one of the most important questions when you're deciding which ice cream maker is best for you!

Well the good news is, the ice cream that comes out of the ICE-30BC is great. As I mention above, it's all about the recipe. And if you put a well balanced mix in the ICE-30BC, you'll get smooth and creamy ice cream out.

If you push it with low fat or low sugar ice creams it can start to struggle. But all these machines find it hard to cope with leaner and less sweet mixes.

I regularly make gelato, Philadelphia and French custard ​ice creams. I've used recipes from David Lebovitz's The Perfect Scoop, Jenny's Splendid Ice Creams at Home, Gelato Messina: The Recipes and Morgan Morano's The Art of Making Gelato.

And the ICE-30BC never lets me down. The only time I have problems is when I try to experiment with my own recipes and I get the mix proportions wrong.

And it's the same with the sorbets and frozen yogurts. As long as I'm careful with the recipes, I get great results every time. 

Wrapping up​

​So I think the ICE-30BC isn't just one of the best of the removable bowl ice cream makers, I think it's once of the best of any domestic ice cream makers period. However it won't be for everyone.

As a summary, I'm going to look at thee things I love about this machine and the things I'm not so keen on. And hopefully that will help make up your mind.

5 things I love about the ICE-30BC​

1. It's robust!​

The build quality of the ICE-30BC is really impressive. It's a well made, heavy duty machine (without being impractically heavy), featuring a powerful motor and durable parts. You can be confident that this ice cream maker is going to perform well and last a long time.​

2. It's simple!

With just one on/off switch it's easy to master! And with no complicated electronics there's nothing that can go wrong. You might need to replace the removable bowl eventually. But they're cheap and widely available.

3. It's dependable!

This robust simplicity means that the ICE-30BC delivers the same consistently good ice creams, sorbets and frozen yogurts every time I use it. 

4. It's got a generous 2 quart capacity​!

​Such a big capacity is unusual in home ice cream makers that don't use salt and ice. And I do really appreciate that extra ice cream if I'm entertaining guests, hosting kids parties, or I just want to stockpile lots of ice cream!

5. It's pretty cheap!​

​Usually less than $70 / £70, that's not a lot to pay for a really well made domestic appliance that will last years and years and consistently deliver top quality frozen desserts and all the pleasure they bring with them!

2 things I don't like about the ICE-30BC

1. The space it takes up in the freezer

Of course, all the ice cream makers with removable bowls take up space in the freezer. But the downside of the generous 2 quart capacity of the ICE-30BC is a big bowl that does take up a lot of freezer space.

In our upright, bottom freezer fridge it only just squeezes in without having to remove the drawer completely. And once in there it pretty much takes up half the available space in that drawer.

2. I need to think ahead!​

Again, this is an issue with all ice cream makers that use removable bowls. But it's worth mentioning again here, because for some people it will be a deal breaker.

You can't just decide you want ice cream, pull out the machine, throw in the raw ingredients and wait for it to churn out the good stuff. You've got to think one day ahead so you can put the bowl in the freezer to properly chill.

For me this isn't really an issue since I make fresh ice cream every week ​and I just store the bowl in the freezer permanently between batches. As soon as the bowl is washed and dried after I've made one batch, I pop it straight in the freezer, so it's ready for the next batch. 

But if you don't have the permanent space in the free​zer and you need to remember to think one day ahead this could become an issue that would stop you buying ICE-30BC.

Alternatives to the ICE-30BC​

With these slight draw backs in mind, ​it makes sense to think of a couple of alternatives just in case the ICE-30BC isn't quite right for you.

Looking for a smaller machine or a smaller bowl?​

​If you think that the ICE-30BC might take up too much space in your kitchen or the 2 quart bowl might not fit in your freezer, then I've got good news...

Cuisinart ICE-21 1.5 Quart Ice Cream Maker

The ICE-​21, also by Cuisinart, is a 1.5 quart ice cream maker that's the smaller brother of the ICE-30BC. It will take up less space in your kitchen and more importantly, the bowl will take up less space in your freezer.

It doesn't look as nice as the ICE-30BC​ and obviously it won't make quite as much ice cream per batch! But if space is an issue then this is a great alternative. It's cheaper too. Check out my ICE-30BC vs ICE-21 page for a full hands on comparison.

Looking for a machine with a built in freezer?

​If you don't want to bother with planning ahead and pre-freezing bowls, Cuisinart also have a fantastic ice cream maker with it's own built in freezer.

Cuisinart ICE-100 1.5 Quart Ice Cream Maker

The ICE-100 is a compressor ice cream maker which means it has it's ​own self powered freezer to chill the mixture. These machines are completely different to the ones with the removable bowls and come with their own advantages and disadvantages.

But one of the major advantages is that if you have an ice cream mix ready you don't have to mess about putting bowls in the freezer. You just turn on the machine, wait half an hour or so for it to fully cool down, pour the mixture in and in half an hour or so your ice cream will be ready.

The ICE-100 is built to Cuisinart's usual high standard ​and produces great quality ice cream, so this a really good choice if you want that extra convenience.

Final thoughts

I think the Cuisinart ICE-30BC is probably the best of the ice cream makers with removable bowls. 

It's really well made, simple and straightforward to use and will undoubtedly last many years. It makes consistently good ice cream, gelato, sorbet and frozen yogurt. And it can make them all in fairly large quantities.

There are some drawbacks that are common to all of the machines with removable bowls. You need to plan a day ahead when you want to use it. And you need to find room in your freezer for the bowl.

If you're not sure if this is the right type of machine for you, check out my guide to finding the best type of ice cream maker where I compare the three different types and show you the simple steps to ensure you find the best type for you.

But if you've decided an ice cream maker with a removable bowl is the way to go, then it's hard to go wrong with the ICE-30BC!

How to choose the best ice cream maker

You don't need an ice cream maker to make ice cream and other frozen treats at home. But a dedicated machine makes everything so much easier. And the quality of the final product will be infinitely better.

So if you're in any way serious about making your own ice cream, eventually you'll start looking at ice cream makers.

But which is the best ice cream maker for you? There's lots of different types at lots of different prices. And it can be confusing when you're just starting out.

Luckily, it's not that complicated. And if you follow a few simple steps it will soon become clear which ice cream maker is best for you.​

There are essentially three different types of modern ice cream maker. And how they differ is in the way they freeze the mixture:

  1. with ice and rock salt
  2. with a removable bowl that's pre-chilled in the freezer
  3. with a built in freezer

But how important is the way we freeze the ice cream? Well, to some extent it's just a matter of convenience...

The ice and salt method is the most inconvenient, being more labor intensive and messy. The machines with removable bowls are more straightforward but require some forward planning. And then the most convenient are the built in freezer models which are really, really simple and straightforward to use.

Let's have a look at each of the three types of machine in more detail...

1. Ice and rock salt ice cream makers​

This is how ice cream used to be made in the old days! With these machines a mix of ice and salt is used to freeze the ice cream.

First, the liquid ice cream mixture is poured into long, metal canister. This canister is then placed in another, bigger container and surrounded by a mix of ice and salt. The mixture is then churned by a big paddle (or dasher) while the ice cools it down.

The salt is used to lower the temperature of the ice even further which helps to freeze the ice cream faster. You can use any type of salt but people usually use rock salt as it's much cheaper.

In the olden days the churning would be done by hand. But with modern machines there's usually an electric motor to do all the hard work. However some modern machines offer both so you can let the motor do most of the work and then finish it off by hand at the end!

These ice and salt machines have a number of advantages. Firstly, since you don't need to pre-chill any bowls, you can start making ice cream as soon as you decide you want ice cream!

Secondly, once you've made one batch, since there's no need to pre-chill anything, you can make another batch straight away.

And thirdly, unlike the other machines, the ice and salt models are often available with big capacities of between 4 and 6 quarts. So you can make lots of ice cream in one go!

However, on the negative side a certain amount of pre-planning is required. You need to make sure you have a plentiful supply of ice and salt. And with all that ice and salt, things can get messy.

You also need to keep a close eye on these machines, adding more ice and salt as needed. You can't just add the ingredients and then sit back an wait for the ice cream. It's quite an involved process.

And of course, if it's a bigger size machine, you've got to think carefully about where you're going to store it.

In my opinion, these machines are best if you don't make ice cream very often. If you're looking for a something to keep in the garage and bring out once or twice over the summer to feed big groups of people at BBQs and parties, then these machines are ideal.

But if you're looking for a machine to make ice cream more regularly, if you want to keep it in the kitchen and you're not trying to feed a small army, then you're probably best off with one of the other types of machine.

2. Pre-freeze bowl ice cream makers

With these machines, the ice cream mixture is frozen in a removable bowl that you need to pre-chill in your freezer compartment. The bowl contains a special gel that gets really cold in the freezer and then transfers that coldness to the mixture as it's being churned later on in the machine.

​The pre-freeze bowl machines have three clear advantages. Firstly, they're much easier to use than the ice and rock salt machines. You simply add the ingredients, turn them on and come back 20-30 minutes later.

Secondly, they don't create any mess. There's no bags of ice and salt to deal with. No melting ice to mop up. They're very neat and tidy.

And thirdly, they're the most compact of the all home made ice cream makers. So they're much more kitchen friendly and much easier to store away.

However there are some very clear disadvantages with these machines too. The bowls need to be pre-chilled for at least 6 hours but preferably overnight. So again, some pre-planning is required.

You need to make sure the bowl will actually fit in your freezer compartment! Check the measurements of each model as the bowls vary in size according to the capacity of the particular machine.

Talking of which, these pre-freeze bowl machines tend to have much smaller capacities than the ice and salt models. They'll generally produce between 1 and 2 quarts of ice cream in each batch, depending on the model. So they're not so good for large groups unless you're pre-preparing several batches in advance.

And remember, because you need to pre-freeze the bowl, you can't make back to back batches. Unless of course you buy an extra bowl and have enough room to store two bowls in your freezer!

I think these pre-freeze bowl machines are best for organised families that like to eat small batches of ice cream regularly. They're compact and tidy. So they look great on a counter top and work well even in smaller kitchens. And they also make it really easy to involve the kids with the whole ice cream making process.

However, if you're really serious about your ice cream, if you want the very best quality, maximum flexibility and ultimate convenience, then you should probably consider the compressor machines.

​3. Compressor Ice Cream Makers

These machines use their own built in compressors to freeze the ice cream. All you do is pour the mixture into the machine, press a button and wait. It's that simple!

There's loads of advantages with these machines. Generally, they're much more convenient to use. There's none of the mess and faff you get with the ice and rock machines. You don't have to remember to put a bowl in the freezer the day before. You never need to stock up on ice and salt.

As soon as you decide you want to eat ice cream, you can start making ice cream. And as soon as the first batch is finished, you can start making the next batch! Which is great if you've got a big family or you're entertaining guests.

They also tend to have more features and options than the other machines. Some of them can be programmed so they are optimized for ice cream, gelato or sorbet. Some will pre-chill the mixture for you. They'll all stop automatically when the ice cream is ready. And some will keep the final product at the right temperature and consistency for an extended period once they've finished. 

The quality of the ice cream from the compressor machines is also the closest you'll get to that produced by commercial machines.

However, there are some disadvantages to these machines as well. They're pretty big and very heavy. So make sure you've thought about where you might keep one. They'll certainly look attractive on your counter top, but check you've got enough room.

And despite their size, they don't have huge capacities. You wont get bigger batches out of these machines than you'll get from the pre-freeze bowl machines.

And of course with a built in compressor and complicated electronics, there's more things that can go wrong. So it's even more important to check the warranty and the after sales service with these machines.

They're also the most expensive of all the ice cream makers. But like most things in life, quality and convenience come at a price. And if you're really serious about making ice cream, then these are probably the machines for you.

Is there really a difference in ice cream quality?​

I've talked a fair bit about the difference in convenience between the three types of machine. But how about quality? Is there also a difference in the quality of ice cream they produce?

One of the biggest factors that determines whether the final product is smooth and creamy or coarse and icy is the speed at which the machine freezes the mixture. The quicker the mixture is frozen, the smoother and creamier the final ice cream.

​And this speed is determined by how cold the container is for the duration of the churning. The salt and ice machines and the built in freezer models maintain a stable temperature for the whole time. But with the other machines, once you remove the bowl from the freezer, it's only going to get warmer.

And this means that the removable bowl machines will be freezing the mixture more slowly towards the end of the churning than at the beginning. 

But does is make a discernible difference in the ice cream?​

Well it can do. The biggest influence on ice cream quality is the mixture recipe. With a good recipe and the right technique you can make fantastic quality ice cream with all three types of machine.

​But if you want to start cutting corners in your preparation or pushing the boundaries of the recipes then you'll notice a degradation in quality with the removable bowl machines before the other two.

The built in freezer models seem to deal better with egg-less or low fat recipes. And for me a least, they seem more consistent in the quality of the final product. 

​However, if you follow all the tip and tricks to keep the mix cold and follow well balanced recipes, you'll get superb quality ice cream for all three types of machine.

Choosing the best type of ice cream maker for you

We know that all the machines are capable of producing great ice cream. ​So, which type you choose will depend on a whole load of other personal preferences.

These include how often you'll be making ice cream, how many people you'll be making it for, and what type of ice cream you want to make.

Here's a reminder of the important features of each type:​

Machine

Capacity

Multiple batches?

Ease of use

Price

Ice and Salt

Up to 6 quarts

Yes

6/10

$ - $$

Pre-freeze Bowl

Up to 2 quarts

No

8/10

$

Compressor

Up to 2 quarts

Yes

10/10

$$ - $$$

And here's a summary of why I think you should buy or avoid each one:

Ice and Salt

Pre-freeze Bowl

Compressor

Good for:

- big families, BBQs, parties​

- big spaces

Good for:

- smaller spaces

- frequent use

Good for:

- no waiting

- multiple batches

Bad for:

- small spaces

​- frequent use

Bad for:

- making lots of ice cream

- unorganized people

Bad for:

- small spaces

So hopefully you've now got some idea of which type of ice cream maker will be best for you. Let's move on and look at some of the different individual models in each group.

Three great Ice and Salt Machines

As we've already seen, the ice and salt style ice cream makers tend to have much bigger capacities than the other machines. Indeed, the three I preview here can all churn out at least 4 quarts of ice cream per batch.

This is twice as much as the other types of machines and it's why the ice and salt ice cream makers are so good for parties, BBQs and large families.

And don't forget ice and salt machines can produce back to back batches. So once the first is finished, as long as you've got enough ice and salt, you can crack on with the next one!

​1. Hamilton Beach 4 Quart Ice Cream Maker (68330N)

​The best thing about this Hamilton Beach ice cream maker is the price! Usually available at less than $30, it's one of the cheapest ice cream machines on the market.

Hamilton Beach 4 Quart Ice Cream Maker

The next best thing about this machine is it's capacity. It can produce 4 quarts of ice cream per batch making it great for big groups and parties.

It's as straightforward to use as other ice and salt machines. Which means you've got to make sure you've got plenty of ice (8 - 12 pounds) and a fair bit of salt (about 3 cups) before you start.

And you'll need to place the machine in a kitchen sink or somewhere else with good drainage, as things can start to get messy once the ice begins to melt.

But as long as you follow the instructions carefully, the Hamilton Beach should produce great quality, soft serve consistency ice cream after around 20 to 40 minutes.

You'll know it's ready as the motor will turn off when the mixture gets to a certain thickness. This is a great feature that should save unnecessary wear on the motor and the gears.

However, this is very much an entry level machine. Apart from the aluminium canister, the construction is entirely from plastic. The motor is slightly under powered and struggles with some recipes. And over time, the gears may wear out making the whole machine unusable.

But despite the doubts over the the long term reliability of this machine it still comes with a 1 year warranty, so if anything goes wrong it that time it can be replaced!

The thing that you need to remember here is that the Hamilton Beach is a budget ice cream maker. If you're looking for something cheap and cheerful that can be used to feed big groups of people a handful of times a year then this is a great choice.

If on the other hand, your looking for a machine to more regularly and want something that's going to last a good few years, it makes sense to look for a machine with a slightly higher build quality...

2. Nostalgia Vintage Collection 4 Quart Ice Cream Maker​

A step up in build quality, the Nostalgia Vintage ice cream maker also features attractive retro styling!

Nostalgia Vintage Collection 4 Quart Ice Cream Maker​

Harking back ​to the olden days of hard churned machines, the Nostalgia features wooden slats and brass hoops. However, these are merely decorative and surround a sturdy plastic bucket that's better equipped than a wooden container to deal with the strains of ice cream churning!

The Nostalgia Vintage will produce 4 quarts of ice cream per batch and like all ice and salt ​machines can make back to back batches.

And while costing just a few dollars more than the Hamilton Beach machine, it features a significantly more robust motor. So not only does it cope better with thicker mixtures, it's also less likely to wear out over time.

Apart from the wooden slats and brass hoops the construction is entirely plastic. And the build quality is obviously not as good​ as the more expensive salt and ice machines.

However, all in all this a very reliable machine. Be aware though it does only come with a 90 day warranty!

3. White Mountain Appalachian 6 Quart ​Ice Cream Maker

The White Mountain Appalachian is the very top of the range when it comes to salt and ice machines.

White Mountain Appalachian 6 Quart ​Ice Cream Maker

It features a genuine pine wood bucket, a 12,000 RPM metal clad commercial grade motor, and a patented triple action dasher. All protected by a five year warranty.

It can make a whopping 6 quarts of ice cream per batch. And the ice cream it produces has a reputation for being the smoothest and creamiest around!

What's not to love? ​Well...

White ​Mountain used to be the ultimate American made, old style ice cream maker. A premium product with a justifiably premium price tag.

However since the company moved manufacturing to China there have been increasing numbers of complaints about the quality of their machines.

Whether all of the complaints are justifiable ​is debatable. However, it seems that some dip in quality has occurred.

But the fact is, if you're looking for a 6 quart capacity ice cream maker there isn't a whole lot of choice. And the White Mountain Appalachian remains by far the highest spec'd machine available.

It's still covered by an impressive 5 year warranty. So if you don't like what you receive, send it back!

Three great Pre-freeze Bowl Machines​

As we've already discussed, pre-freeze bowl machines are great for regular use in smaller kitchens. They're really straightforward to use, they don't make any mess and ​they're all pretty cheap.

The removable bowl market is dominated by Cuisinart. And the quality of their machines is so good I wouldn't recommend buying any other brand.

1. Cuisinart ​ICE-30BC Pure Indulgence 2 Quart Ice Cream Maker

The Cuisinart ICE-30BC is one of the most popular ice cream makers ​on the market. And with good reason.

Cuisinart ​ICE-30BC Pure Indulgence 2 Quart Ice Cream Maker

It's well made, ​compact, easy to use and makes consistently good ice cream. It was the first ice cream maker I bought and I still use it today.

It can make 2 quarts of ice cream per batch which is at the top end of what you'll get from a non ice and salt machine. 

The freezable bowl is thick and sturdy and is double insulated so it cools evenly and warms slowly. However, since it's a big 2 quart bowl, check you've got enough space in your freezer before you buy it!

The controls are simple, just "on" and "off". But most importantly the motor is very powerful. This means it always get's the job done and there's none of the gear slipping and screeching you get with cheaper machines.

Sure, it's not quiet. But automatic ice cream machines are never quiet. And you have to remember to pre-freeze the bowl the night before you make a batch. But that's the same for all these machines.

So, unless your planning on making ice cream for big groups, I think this is one of the best entry level ice cream makers available today. Check out my complete review of the ICE-30BC.

2. Cuisinart ICE-21 1.5 Quart Ice Cream Maker

The Cuisinart ICE-21 is essentially the baby brother of the ICE-30. It works in exactly the same way but has a 1.5 quart capacity rather than the 2 quarts you get with the ICE-30.

Cuisinart ICE-21 1.5 Quart Ice Cream Maker

This means that the whole unit is smaller. ​And lighter. And the bowl takes up less room in your freezer! 

To be honest the finish does look a little cheaper and less well made. However, in my experience this is purely visual. It's as well built and performs just as well as the ICE-30BC​.

So choosing between them is just a matter of deciding which capacity suits you best. To some extent this is about how much ice cream you eat. People that eat more will tend to prefer the larger capacity machine.

You can check out my complete review of the ICE-21 here.​ Or see how it measures up to the ICE-30BC in my full, hands on ICE-30BC vs ICE-21 comparison.

3. Cuisinart ICE-70 2 Quart Ice Cream Maker

If the ICE-21 is the baby brother of the ICE-30BC, the ICE-70 is it's flashy uncle. It has the same 2 quart capacity but replaces the simple manual "on/off" button with a small LCD screen and control panel.

Cuisinart ICE-70 2 Quart Ice Cream Maker

You don't get that much extra functionality with the ICE-70. But depending on your priorities it could be worth the slightly higher price tag.

The most interesting feature is the ability to optimize the machine for 3 different types of frozen dessert. By choosing either "ice cream", "gelato" or "sorbet", you set the machine to rotate at a specific speed and for a specific length of time which best suits that particular dessert.

For gelato, the idea is that a dasher that rotates slower for a longer period of time will beat less air into the mixture and give you a denser more gelato like final product.

For sorbet the dasher rotates at the default speed but for longer again which should suit it better. And for ice cream it rotates at the default speed again but for less time.

You can also adjust the timer to any duration you like. Once it's done, it will beep every 5 minutes for 30 minutes or until you turn it off. 

For me the timer is not super useful. There are plenty of other ways to time the machine. But the ability to control the density of the final product will be really attractive for those interested in gelato and sorbet.

Otherwise the ICE-70 is pretty much the same as the ICE-30. It's a slightly bigger machine. But the ice cream, it produces is of the same quality. So really it's just a case of deciding whether those extra features are worth the extra cost.

Check out my full, hands-on Cuisinart ICE-70 review. ​And I also have a detailed Cuisinart ICE-30BC vs ICE-70 comparison!

Three great Compressor Machines

The machines with built in freezers are perhaps the most convenient of all the ice cream makers. And they're certainly the most expensive!

They're best suited to families with a little more space, who make ice cream regularly and want the whole process to be as simple and straightforward as possible.

With all of these machines there's always a possibility that there's something wrong with the freezer when you receive it. The compressors can easily arrive damaged and in this case they just won't work properly at all. In this case you have a dud!

However this should be obvious as soon as you make the first batch of ice cream. And as long as you bought it from a reputable outlet there should be no problems returning it for a working replacement.

There's quite a few to choose from and to a large extent it's a case of deciding whether the extra features that some of the machines provide are worth the extra cost. Let's have a look at three of the best...

1. Cuisinart ICE-100 1.5 Quart Ice Cream Maker

Another machine from Cuisinart. And it's another winner. Whether it's removable bowls or built in freezers, you can rely on Cuisinart to produce really good ice cream makers!

Cuisinart ICE-100 1.5 Quart Ice Cream Maker

The ICE-100 is relatively simple compared to some of the other machines. But everything it does, it does really well.​

It has a 1.5 quart capacity and uses a removable aluminium bowl to make cleaning easier. The transparent lid allows you to see what's going inside and has an opening that makes adding extra ingredients simple.

​It's the only machine that has 2 different paddles: one for ice cream and one for gelato and sorbet. This is because gelato and sorbet generally contain less air than ice cream and a different shaped paddle can limit the amount air that's beaten into the mixture. This is a really useful feature if you're interested in trying different types of frozen treats!

You can turn the freezer on before you start churning to make sure it's as cold as possible when you add the mixture. And there's a timer so you can set the machine to churn for up to 60 minutes. Once the set time is reached, the machine will stop churning but will keep your ice cream cold for up to 10 minutes.​

You do need to bear two things in mind​ with this machine. Firstly, although it's supposed to have having a 1.5 quart capacity, it struggles to contain more than 1.2 quarts with the mixture sometimes overflowing the edges of the bowl. Secondly, small amounts of mixture can sometimes get into the gear on the bottom of the bowl and if they're not cleaned up they will go rancid over time and produce a nasty smell.

However neither of these issues are insurmountable. ​Firstly, since it can make back to back batches you can simply make slightly smaller quantities per batch. And secondly the seal over the gear can be removed so it's not difficult to clean any stray mixture should it enter the gear.

All in all this is a very reliable, simple to use machine. It come s with a 5 year warranty in the UK and a 3 year warranty in the US. And it makes great ice cream with no fuss!

2. Whynter ICM-200LS ​2.1 Quart Ice Cream Maker

​The Whynter ICM-200LS is very similar to the Cuisinart ICE-100 in terms of the range of functionality it offers.

Whynter ICM-200LS ​2.1 Quart Ice Cream Maker

But there's one significant difference: it has a 2 quart capacity. This is unusually big for built in freezer machines, especially at this price range. And if you like to make large amounts of ice cream it's a big bonus.

Other than that, it's very like the Cuisinart machine. There's a transparent lid with an opening that lets you add extra ingredients. The timer defaults to 60 min but can be set to any time less than that. And once it's finished churning it automatically keeps the mixture cool for 10 minutes.

Beyond that you can also set the machine to churn without cooling ​(which is useful for pre-mixing ingredients or adding extra ingredients at the end). And you can also set it to cool without churning (which is good to pre-freeze the bowl or keep the mixture cool for longer at the end).

This is reliable machine with a big capacity. There's not so many bells and whistles. But if you want a reasonably priced machine that can knock out big, back to back batches of ice cream this would be a good choice.

​3. Breville BCI600XL Smart Scoop 1.5 Quart Ice Cream Maker

The Smart Scoop is the machine with all the bells and whistles. Whether you prefer full manual control or want a completely automatic experience, this machine can deliver both. 

Breville BCI600XL Smart Scoop 1.5 Quart Ice Cream Maker

In automatic mode you simply choose one of four options: ice cream, gelato, sorbet or frozen yogurt. The machine then does the rest: churning and cooling the mixture in the optimal way for each.

If you want to get more involved, there are 12 hardness settings to choose from with the machine automatically adjusting itself to achieve the desired consistency.

All these automatic settings can also be overridden by using the machine in manual mode. Here you can simply set the machine to run for any time between 5 and 180 minutes. But don't worry: if the mixture gets too thick it will automatically stop anyway.

Once the mixture stops churning it goes into a keep cool mode which can maintain the ice cream in the desired condition for up to 3 hours!

It will even play some music when it's finished​, with a choice of 3 in built tunes. Of course, if you're not keen on this touch the music can be turned off!

​There are plenty of other touches you don't get with the other machines. There's a child lock on the lid to stop over unenthusiastic fingers wandering into the mix. There's a an audio alert that lets you know when it's the best time to add extra ingredients. And you can toggle the temperature read outs between Fahrenheit and Celsius.

​As I said, this is the best ice cream maker for those that want maximum convenience and loads of extra features.

Read my full, hands-on review of the Breville Smart Scoop ice cream maker where I discover whether all these fancy features are really worth the extra money!

Wrapping Up​

So those were a selection of the best ice cream makers available at the moment. It's clear to me that the best machine for you will depend on how you'll be making ice cream. 

If you're making ice cream for irregularly for really big groups of people at parties and BBQs then you'll need a machine with a big capacity and maybe one that can churn out back to back mixes.

In this case an ice and salt machine might suit you best. These are available with 4 and 6 quart capacities. And as long as you've got enough ice and salt you can make a new batch as soon as the first ones finished.

In which case, if you're on a very tight budget and you're not looking for a machine that's going to last a long time, the Hamilton Beach 4 Quart machine is really, really cheap. Just be aware that you might not get too many hours use from it before the motor starts to go.

If you're able to spend a just a little more money, the Nostalgia Vintage Collection 4 Quart machine is much more robust with a far stronger motor. And it should last significantly longer.

And if 4 quarts ​isn't enough, not only will the White Mountain Appalachian machine give you 6 quarts per batch, it's also got a significantly better build quality than both of the other machines. And as long as you look after it, it should last many years.

If you're making ice cream ​more regularly for smaller numbers of people and have limited space or a limited budget, then a machine with a removable bowl could be the best choice for you.

Cuisinart are the best brand to go for here. The ICE-30BC offers very simple, straightforward functionality and 2 quarts per batch.

While the smaller ICE-21 will give you 1.5 quarts and might be better if you have less space or just don't need ​so much ice cream!

The ICE-70 also has a 2 quart capacity and can be optimized for ice cream, gelato or sorbet, so it's a great choice for those that like to experiment!

But if you've got the space and can afford to spend a little more, the convenience of an ice cream maker with a built in freezer might be the best choice.

Cuisinart again do a fantastic job with the ICE-​100, producing a reasonably priced, dependable machine that will knock out 1.5 quarts of quality ice cream time after time.

If you need more ice cream then the Whynter ICM-200LS will give you 2.1 quarts ​per batch and similar functionality to the Cuisinart machine.

And if you want an all singing (literally) all dancing machine that can do everything for you, the Breville BCI600XL Smart Scoop is packed full of features that make ice cream making as simple and straightforward as possible.

I hope this post has been helpful. If you have any questions or comments, please let me know below...​

Ice cream Science

The Science of Ice Cream. Sounds a bit heavy doesn’t it? Maybe a bit boring? You just want to get on with inventing crazy flavor combinations don’t you?

Hold on though. Not only is it actually really interesting, a basic scientific understanding of the ingredients and the way they work together will also help you make much better ice cream.​

Science will help you in two important ways:

  1. When something’s not working, it will help you fix it
  2. ​When you want to start inventing, it will help you do so successfully.

​So in this post, I’ll give you a fuller understanding of what ice cream is. I’ll introduce the individual components, highlight the special contribution of each and explain how they all work together in the final product.

Finally, I’ll describe the five stages that we go through to make ice cream and why each one is important.

I’ve tried to explain everything in as clear and straightforward way as possible. So there shouldn’t be any parts where you’re scratching your head in confusion.​

But I’ve also tried to go into as much depth as possible to give you a complete understanding of what’s going on. This means it’s quite a long post! If there’s anything that’s not clear let me know and I’ll try to expand and improve.​

So, make yourself comfortable and lets get started…

What is ice cream?​

Ice cream is an very complex, intricate and and delicate substance. It includes all three states of matter at once: solid (ice and fat), liquid (sugar solution) and gas (air bubbles).

These states exist in a precarious balance. And it’s in that balance that we find the unique sensory qualities that so enchant us!​

Essentially, tiny particles of sold ice and fat surround and support air bubbles in a thickened sugar solution.

The basic structure of ice cream

Let’s look at each of these four components in more detail...

Component #1: Ice

Ice crystals give ice cream it’s firmness. They give it body and solidity. That resistance to your spoon and your tongue: that comes from the ice crystals. About 30% of ice cream is made up of ice crystals.

Ice crystals are formed from the water in the mixture as it starts to freeze. You might think that there's no water in ice cream. We don’t usually add any directly. But don’t forget milk and cream are mostly water. Milk is 90% water. And cream is around 60% water.

The size of these ice crystals is very, very important! Small ice crystals will make the ice cream smooth and less cold in the mouth. While large ice crystals will give the ice cream a grainy, coarse texture and a cold, icy mouth feel.​

(This apparent difference in temperature is because larger ice crystals require more heat to melt. Since this takes heat away from your mouth, it makes the ice cream seem colder.)

Different people like different types of ice cream but one thing's for sure: good ice cream should be smooth. So keeping those ice crystals small is one of the most important parts of making quality ice cream.​

​Component #2: Air

​Air gives ice cream it’s softness. It keeps the ice cream pliable and makes it easy to scoop. The air also contributes greatly to texture and consistency. Ice creams with more air are lighter, fluffier and less "creamy". While ice creams with less air are heavier, more dense and more "creamy".

Air bubbles are added to the ice cream by the paddle (also known as the dasher) that churns the mixture as it freezes. The faster the blades of the dasher move through the mixture, the more air they add. And different shaped dashers will also affect how much air is pushed into the mix.

The air bubbles also give ice cream most of it’s volume. The amount of air in ice cream is measured by something called "overrun". This is simply the increase in volume that the air contributes to the ice cream (measured as a percentage).

So, if you start off with 1 litre of ice cream mix and once churned it’s 1.5 litres, the volume has increased by 50%. And so the over-run would be 50%.

So called “premium” ice creams tend to have lower overrun (around 25%). While cheap ice creams can have as much as 100% overrun. Why? Since air is free, it’s a very efficient way to increase the volume of your product without increasing the manufacturing cost!

Different types of ice cream also have different levels of overrun. Italian gelato for instance can have an overrun as low as 20%.

Brooklyn Brainery did a great study on the different levels of overrun in a variety of popular American ice creams. ​I'm providing a summary in the table below...

Ice cream Brand

Overrun %

America's Choice Tub o' Vanilla

102

America's Choice Premium "Vanilla Bean"

97

Breyer's "Homemade Vanilla"

98

Turkey Hill "Vanilla Bean"

104

Haagen Dazs "All Natural Vanilla Ice Cream"

31

Stonyfield Farm "Gotta Have Vanilla"

31

Ronnybrook "Hudson Valley Vanilla"

22

"Artisan" gelato

20-25

Is it best to have a higher or lower over-run? Ultimately it’s all down to personal preference: if you like light, fluffy ice cream, you’ll want to make it with a high over-run, if you like dense, creamy ice cream you’ll be looking to make it with low over-run. For home-made ice cream this can be influenced by which machine your buy.

Component #3: Fat​

Fat contributes to ice cream in four important ways: 1) it helps to stabilize the final structure by trapping air bubbles 2) it thickens the mixture which slows melting, 3) it delivers flavour and 4) it gives that lovely creamy texture and mouth-feel.​

The fat in ice cream mostly comes from the milk and cream and is called butterfat. Around 3.4% of whole milk is fat. While cream can vary between 30 and 48% fat, depending on what type is being used. So mostly it comes from the cream!

This fat exists as tiny, solid globules suspended in the milk and cream. But how do these fats globules stabilize the ice cream?

Well, before the mixture is churned the fat globules are very small and are kept apart from each other (more on this later). However, while the ice cream mixture is being churned, the fat globules bang together and join up to form long, pearl like strings that wrap around the air bubbles.

​These strings hold the air bubbles in place, keeping the “foam” stable. This is how the ice cream maintains it’s volume, light texture and soft consistency: all the qualities that the air bubbles contribute to ice cream.

The fats also give ice cream it’s creamy texture and richness. Higher fat ice creams are rich and creamy with a long lingering after taste. Lower fat ice creams have a much lighter, cleaner flavour with a short lived after taste.

Interestingly, any additional flavours (fruits, chocolates, nuts etc) in the ice cream are also affected by this. This is because the fat tends to hang onto these flavours.

So the fruit flavour in a strawberry ice cream will be delivered more slowly and subtly (but more long lastingly) in a higher fat ice cream. And will usually be more clearer and prominent (but relatively short lived) in a lower fat ice cream.

Whether you prefer higher fat, rich and creamy ice creams or lighter, cleaner lower fat ice creams is a matter of personal taste. American and French ice creams tend to be higher in fat. While Italian ice creams are usually a bit leaner.

You can alter the fat content of your own ice cream by playing around with the proportions of milk and cream in your base mixture. Higher fat ice creams have more cream, while lower fat ice creams have more milk. You need to be careful though: too much or too little fat will can ruin your ice cream...

Too much will give an unpleasant, cloying flavour, a grainy texture from the crystallisation of the fat particles and it will probably freeze into a hard solid block because of the excess fat solids.

Too little and there wont be enough fat globules to form the strands that stabilize the air bubbles so the ice cream will be wet and coarse and melt easily.

Component #4: Sugar Solution​

This is the liquid part of ice cream. It’s in this solution (also called the matrix) that the ice crystals and fat globules (solids) and the air bubbles (gas) are suspended.

But what does it consist of? Well essentially there are 3 elements: water, sugars and proteins. Let’s look at each in turn...

Water​ in the sugar solution

As we already know, the water in ice cream comes from the milk and cream. Some of this water freezes into solid ice crystals. But some of it will remain in a liquid state even at 0°F / -18 °C. 

Hold on, water freezes at 32°F / 0 °C, so how can this be? Well, the sugar that’s dissolved in the water lowers the freezing point of water which prevents ice crystals from forming.

The initial concentration of sugar in the water does allow ice crystals to form. But as more ice crystals grow, there’s less free water so the concentration of sugar in the remaining water increases. This further lowers the freezing temperature until a point at which the remaining super sweet water will not freeze, even at 0°F / -18 °C.

In this way a proportion of ice cream always remains liquid.​

Sugars​ in the sugar solution

Some sugar (lactose) occurs naturally in milk and cream. But the vast majority of the sugar in ice cream is added separately by us.

We can add loads of different types of sugar to ice cream. And they all play the same role: they make it sweet and they keep it soft. But different sugars will do each of these to different extents.

Sugar provides sweetness​...

All sugars obviously add sweetness. But different types of sugar are less or more sweet. The sweetness of different sugars is measured against that of table sugar (sucrose).

... and ice crystal retardation​

All sugars lower the freezing point of water which stops ice crystals from forming. More sugar means less ice crystals. And less ice means a softer ice cream. But different types of sugars lower the freezing point to different degrees.

This is why you’ll often see ice cream recipes that include several different types of sugar. By mixing them up we can fine tune the sweetness and softness of the final ice cream.

Milk Solids Non Fat​ in the sugar solution

It sounds very technical but Milk Solids Non Fat (MSNF) are just the proteins, lactose and minerals found naturally in milk and cream. Cow’s milk is around 87% water, 4% proteins and 4.8% lactose with the remainder being salts and minerals.​

The proteins have two very important functions in ice cream: 1) they help the fat globules trap the air bubbles and stabilize the final product and 2) they contribute to the characteristic dairy flavour.

In some recipes you will see the addition of Skimmed Milk Powder (SMP). Since skimmed milk powder is essentially milk protein and lactose, these recipes are simply increasing the MSNF component of the mixture.


So that was a quick look at the basic components that make up all ice creams. Their chemical structure and the way they interact under different conditions are what makes ice cream, well, ice cream!

However, these relationships are fragile and we can add two other components to help strengthen them and improve the quality and stability of the final product. They go by the rather scientific names: Stabilizers and Emulsifiers.

​Emulsifiers

The role of emulsifiers in ice cream can be a little bit confusing. So let’s start with the basics…

​What is an emulsion?

An emulsion is a mixture of two or more liquids that are not normally mixable! By not normally mixable, I mean that one won’t dissolve in the other.

The most obvious example of an emulsion is an oil and vinegar salad dressing. Neither the oil nor the water will dissolve in the other. But when we combine the two and stir vigorously, the oil is broken up into tiny particles which are dispersed evenly throughout the water to create a consistent mixture. This is an emulsion.

A less obvious example of an emulsion is milk! Milk is basically an emulsion of liquid fat globules in water.

Now emulsions are by their nature unstable: remember they consist of liquids that are not normally mixable. And left to their own devices they will separate. A salad dressing left on the shelf will separate into two layers of oil and water.

​And milk straight from the cow will quickly separate into two layers: fatty cream and watery milk. This happens when the fat globules in the milk cluster together, separating from the water.

However, the milk we buy in the supermarket is “homogenised”. When milk is homogenised it is essentially mixed vigorously under high pressure. This breaks up the fat globules into much smaller particles.

These smaller, weaker particles attract proteins in the milk which interfere with the natural inclination of the fat globules to cluster together. And if they can’t cluster together, the milk can’t separate into cream and milk.

​So when milk is homogenised the natural emulsion is strengthened, making it much more difficult for it to separate into milk and cream.

​What’s this got to do with ice cream?

The purpose of milk homogenisation is to create a stronger emulsion where the fat globules are unable to cluster together. But remember: for ice cream we need the fat globules to cluster to form the long strands that will hold the air bubbles in place.

So when we make ice cream we actually need to de-emulsify the milk to emulsify the ice cream!

How do we de-emulsify the milk?

It’s the proteins attached to the fat globules that are preventing those globules clustering together. So we need to remove the protein molecules from the fat globules. And this is where emulsifiers come in.

Any emulsifiers in the mixture will attach themselves to the surface of the fat globules, displacing many of the proteins. And the emulsifiers don’t interfere with the natural inclination of the fat globules to cluster together in the same way as the proteins do.

But what are these magic emulsifiers? And where do them come from? Well, in home-made ice cream they often come from eggs! Or more specifically egg yolks.

Egg yolks contribute three important things to an ice cream mixture: fat, protein and a chemical called Lecithin. And it’s the Lecithin in eggs that acts like an emulsifier: displacing the proteins on the membranes of the flat globules and allowing those globules to cluster again.

Of course you can make ice cream without eggs. Some Italian gelatos use cornstarch or tapioca starch instead, which amongst other things fill the emulsifying role of eggs. And of course commercial ice cream manufacturers prefer synthetic emulsifiers such as Polysorbate 80.

But if you don’t use something as an emulsifier, your ice cream wont have the same smooth texture and solidity as those made with emulsifiers. This is why Philly style ice creams tend to be coarser and more fast melting with less body: they don’t use eggs or any other emulsifiers.

Check out my emulsifier page for lots more information about these magic ingredients and how to use them properly.

Stabilizers

Just like emulsifiers, stabilizers can also improve the texture and structure of ice cream. But they do it in a different way.

Stabilizers act a bit like sponges, soaking up any excess water in the ice cream mixture. This will obviously thicken the ice cream. By holding onto that water it also slows melting. And it also helps prevent the growth of ice crystals during storage, so the ice cream maintains a nicer texture for longer.

Most stabilizers are derived from plants. However, some come from bacteria or animal origins.

Stabilizers are used in pretty much all commercial ice creams. This is largely to guarantee a long shelf life for their products. But in home-made ice creams they are less common. And in fact many purists are wary of them.

I don’t take this line at all. Making the best possible ice cream is my main priority. As home enthusiasts on small budgets we’re already handicapped by limited machines and freezers. So if I can use a perfectly natural and safe ingredient to improve the quality of my ice cream I want to at least try it out.

Having said that some people have intolerance's to the stabilizers. So you’d be wise to check that out if you plan on using them!

For more information on the different stabilizers​, how they can improve our ice cream and the best ways to use them, check out the stabilizer page!


OK, so we’ve looked at all the four key components that make up ice cream. And we should have a pretty good idea how they work together in the final product. But how do these raw ingredients come together to make ice cream?

Let’s look at the five stages of ice cream production and see how each stage contributes to the final product.

The Five Stages of Ice cream Production

  1. Preparing the mix
  2. Pre-chilling
  3. Ageing
  4. Freezing
  5. Hardening​

Stage 1: Preparing the mix

This is all about the recipe. And it’s probably the most important stage in the whole process. Because if we get this wrong it doesn’t matter what happens in the next four stages: our ice cream will be rubbish.

This means we’ve got to make sure we’ve got the right amounts of each ingredient so that we have the ideal proportions of fats, sugars and solids.

Once we're sure the recipe is balanced, it's time to heat the mix. This serves two purposes. Firstly, it pasteurizes the mixture, which is important for health reasons. And secondly, it encourages the "denaturation" of the milk proteins, which will help produce a more stable end product.

i) Pasteurization​

Home-made ice cream generally uses pre-pasteurized milk. But if the mixture contains eggs, they need to be pasteurized by us. This is to kill any dangerous bacteria such as Salmonella which may be present.

​Traditionally we would heat the mixture to 85°C (185 °F). However, if we want to reduce the eggy flavour in the final ice cream we could instead keep the mixture at 69 °C (156 °F) for 20 minutes.

This will also pasteurize the eggs and thicken the mixture. But it keeps the mixture beneath the 72 °C (162 °F) at which egg proteins start to denature, releasing that characteristic eggy flavour.

Sometimes that flavour is desirable. But if it’s not and we still want to take advantage of the thickening and emulsifying properties of egg yolks, this is an option!

​If there are no eggs in the mixture, then there’s no need to pasteurize it. However, there are a couple of good reason why it’s a good idea to heat it up anyway:

  1. It can help infuse any added flavours into the mix
  2. It can help with milk protein "denaturation"

ii) Protein denaturation

When we heat the mixture the whey proteins in the milk undergo partial protein unfolding which is also know as denaturation. Essentially this just means that their structure changes under the stress of the heat.

However, this new structure is more inclined to stabilize the air bubbles in the ice cream. So what it means for us is a smoother, more stable final product.

​Stage 2: Pre-chilling

​Once the mixture has been pasteurized, it should be cooled down as quickly as possible. This is to minimize the time it remains between 45 °C (113 °F) and 15 °C (59 °F) which is when harmful bacteria can re-develop.

​Ideally, we should place the mixture in an ice bath until it reaches room temperature and then transfer it to the fridge where it will continue to cool down to 4 °C.

​This pre-chilling also contributes to a smoother texture in the finished ice cream. There's a close relationship between the amount of time the mixture spends in the ice cream machine and ice crystal size in the final product. Essentially: the less time in the machine, the smaller the crystals.

So clearly we should do all we can to reduce the time the mixture spends in the machine. And by adding a mixture that's already chilled, we help the machine do it's job more quickly, which means smaller crystals and a smoother final ice cream.

If you pre-chill the mixture in the fridge overnight it will also benefit from "ageing". But what is ageing?

Stage 3: Ageing​

​Keeping it in the fridge overnight will obviously allow any flavors we’ve added to the mixture to develop more depth.

But it also encourages two chemical changes which will encourage the mixture to hold air better once it’s being churned and produce a more stable final product:

​Firstly, the fat globules start to crystallize. This is where small, spiky crystals emerge from the surface of the globules. Once the mixture is being churned, these pointy crystals will help globules stick to other globules to form the long stings that hold the air bubbles in place.

Secondly, any emulsifiers in the mixture (either from the eggs yolks or other sources) will start to displace the milk proteins on the surface of the fat globules. Remember, it’s these proteins that were helping keep the milk homogenized by discouraging the globules from clumping together.

​So, with the milk proteins gone and these spiky needles protruding from their surface, the fat globules are now primed for "partial coalescence". This is when they will start to clump together to form the scaffolding that supports the structure of the final ice cream!

Stage 4: Freezing​

​The ice cream mixture is then added to a machine which simultaneously chills and churns it. In doing so it makes three important changes to the mixture which will transform it into ice cream...

​1. Creates ice crystals in the mixture

The ice cream mix sits in a container within the machine. The outside of this container is cooled rapidly and the mixture that's touching the sides of the container begins to freeze, forming ice crystals.

In the middle the container is a rotating “dasher” with blades that scrape against the sides. As it rotates, the blades scrape the ice crystals off the sides and moves them into the middle of the mixture.

The displaced ice crystals further cool the rest of the mixture. And the space they leave on the sides is rapidly filled by new ice crystals.

Then as the dasher continues to rotate, the new ice crystals are scraped away again. And so it goes on, with more ice being distributed throughout the mix as it cools down.

​2. Adds air to the mixture

​The blades of the dasher also push pockets of air into the mixture. Then as they turn, the blades break these pockets into smaller and smaller air bubbles which are evenly distributed throughout the mix.

These small, evenly distributed air bubbles are essential for a smooth, stable final product.

3. Encourages partial coalescence​

​The dasher blades fulfill one other very important function. By churning the mixture they cause some of the fat droplets to collide and join together or “coalesce”. This is where we see the benefits of the ageing stage...

​The emulsifiers that replaced the proteins on the surface of the fat globules during ageing have already weakened the stability of the emulsion. And now as the fat globules are mixed, the spiky crystals (which also formed during ageing), pierce the layers of other fat globules as they collide, allowing them to stick together more easily.

This process is called partial coalescence. And the partially coalesced fat droplets are known as de-emulsified or destabilized fat.

More importantly, this coalescence creates the strings of fat globules that wrap around the air bubbles and hold them in place. So ironically, it is the destabilized fats which stabilize the air bubbles in the final ice cream!

There is an important balance to be maintained here. If there’s too much protein or not enough emulsifiers in the mix, the emulsion will be too stable, and the fat globules won’t coalesce. While if there’s not enough protein or too many emulsifiers, the emulsion will de-stabilize and too much of the fat will coalesce.

Too little partial coalescence and there may not be enough fat to hold the air bubbles in place. This will result in an unstable foam that’s wet and coarse.

Too much partial coalescence and the coalesced fat droplets become so large you can feel them in your mouth. Known as “buttering”, this isn’t pleasant either!

​The final ice cream starts to come together

As more and more water starts to freeze into ice crystals, the mixture starts to thicken. Since there's less water, the sugars in the remaining water become more and more concentrated.

This further reduces the freezing point of the mixture until at last the remaining liquid contains too much sugar to freeze further.

​At the same time, the beating of the blades and the emulsifiers in the mixture encourage the fat globules to group together and coalesce. They form strings which together with the proteins trap and stabilize the air bubbles that are introduced to the mix by the rotating blades.

And so here we have the three states in a delicate balance. The solid ice crystals, the air bubbles and the super sweetened liquid cream.

Commercial vs Domestic set ups​

Commercial ice cream machines (also called batch freezers) have two significant advantages over the ice cream machines we use at home: 1) they can freeze the mixture much faster and 2) they can add more air to the mixture.

​We already know that smaller ice crystals mean a smoother ice cream. The faster the mixture is frozen, the less time the small, newly formed ice crystals will have to grow into large, coarser crystals.

The mixture should leave your fridge and enter the machine at about 4 °C. The machines job is to cool it to between -5 °C and -7 °C (23 °F and 19.4 °F). Commercial machines can do this in less that 15 min. Domestic machines may take as long as 30 min. And it’s during this extra time that the small crystals can grow.

​There’s not a lot we can do about this. Except get the mixture as cold as possible before we put in in the machine.

Stage 5: ​Hardening

When it reaches about -6 °C (21 °F) the ice cream should be removed from the machine. At this point it is still very soft with a consistency much like soft serve ice cream. So we transfer it to a freezer to harden.

​Commercial vs Domestic set ups

This is another area where the domestic set up can’t match up to the commercial operations. Ideally the ice cream should be cooled to -35 ° C (-31 °F). At this temperature, further ice crystallisation is impossible so the ice cream will remain smooth.​

​Unfortunately, domestic freezers won’t reach these temperatures so we just need to content ourselves with cooling the ice cream as quickly as possible.

​If you want to eat it all the same day (and why not?), you should cool it to around -12 ° C (10 °F) which is its ideal serving temperature.

​But if want it to last more than a couple of days you need to get it down to -18 ° C (10 °F) as quickly as you can. However home made ice cream is not meant to be stored for long periods of time and you won’t get much more than a week before the quality really starts to deteriorate.

Wrapping Up​

​I hope that this post has given you a solid understanding of the science behind ice cream. Not only is it pretty interesting (I hope!). It should also help you understand how to fix things when they go wrong and how to experiment within the bounds of what is scientifically possible!

As always, if you have any questions or comments, please let me know below…​

About me

It all started in Rome. As these things so often do.

We were on a long weekend away. Sleeping in a pokey little room in a depressing apartment somewhere near the center of town. Trying to catch some early spring sun after a miserably long winter in London.

And we were having a nice enough time. We’d been to the Coliseum. We’d eaten some rabbit stew in an alleyway in an old part the city. We’d drunk a fair bit of wine. We’d even been to watch Roma play football.

And we’d eaten a lot of ice cream. Or gelato as the Italians call it.

Everywhere you go in Rome there are ice cream shops (or gelaterias). Vast windows, crammed full of metal trays that overflow with brightly coloured, carefully sculpted mounds of different flavoured, iced creams.

These gaudy displays were hard to resist. So we didn’t. And they must have tasted OK as we kept going back for more. But I really don’t remember any of them.

However, someone I knew had recommended a very particular gelateria. Or maybe I’d read about it in a guidebook. I don’t remember now. This was a long time ago. Way before smart phones.

Anyway, this place was up somewhere near the Trevi fountain. So one evening after a quick look at the baroque water feature, we went to check it out.

I think we arrived just as it opened as it was pretty much empty. But it was immediately, obviously different from the other gelaterias we’d visited.

There were no great waves of exotically coloured cream on display. Just a white counter with a few sunken metal buckets under shiny lids. And a small sign next to each lid telling you which flavour lay hidden within.

As we entered, two workers wearing crisp white uniforms and serious expressions emerged from the back with fresh buckets of gelato to add to the counter. To be honest, it seemed more like a chemistry lab than a gelateria.

Anyway, we chose our ice creams, sight unseen. She had mandarin, I had fig. We made our way outside. And we sat on a wall outside, kicking our heels as we gave the small tubs of gelato exploratory licks…

And…

And it was the most incredible thing I’d ever tasted.

It’s difficult to describe. But it was like the very purest essence of perfectly ripe fig, delicately balanced in a perfectly cool, perfectly smooth, perfectly clean, milky suspension. Super intense but not in any way overpowering or cloying.

I’d never tasted anything like it. And her’s was pretty good too.

So that was when it started.

We never went back to that gelateria. And I’ve never been back to Italy. But that one ice cream on that cool spring evening in Rome always stayed with me and it started a long, enduring obsession.

Wherever I am, whatever I’m doing, I’m always looking for “the perfect ice cream”. But until now it’s always proved elusive. Nothing I’ve bought has ever come close to the way I remember that simple fig gelato.

So more recently I’ve started making my own. And I’m not there yet. But I’m getting closer to that perfect ice cream every day!

We can all make the most amazing tasting ice cream at home.We should all make ice cream at home.

The stuff you buy in the shops will never taste anything like as good as the stuff you make at home. You have complete control over what goes in or what stays out. How healthy (or unhealthy) it is.

You can experiment with all sorts of crazy flavours. And the great thing is: even the strangest flavours usually taste pretty good in ice cream. It’s hard to go wrong.

So I’ve started this website to try and make the best online homemade ice cream resource. I’ll add everything I’ve learned and everything I’m going to learn.

I hope you find it useful.