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Knox Gear Ice Cream Maker Review

The Knox Gear Automatic Ice Cream Maker is one of the cheapest compressor style ice cream machines currently available.

Does that mean it's also one of the worst compressor style machines currently available? Or does that mean it's a bargain? Read on my friends, and we'll find out!

But before we start, some clarification. The Knox Gear is one of many ice cream makers in what I call the "third tier" of compressor machines.

These are ice cream makers that are manufactured in China by a company called Foshan Nodika and then white labelled by various other companies around the world.

So for example, in mainland Europe, the Knox Gear machine is sold by a company called Domo. And in the UK it's called the Emma!

Does that mean it's dodgy? No not at all. Foshan Nodika has been around for a few years and make many of the ice cream makers we all know well. They know what they're doing. And they do it well!

But hopefully, knowing that so many of the ice cream makers you're considering buying are made by the same company, will help make a decision, because the truth is: there's not a lot of difference between them!

Knox Gear Specs

Width:

11"

Height:

9.5"

Depth:

15.25"

Weight:

27 lb

Loudness:

79-83 Db

Paddle Rpm:

56

Overrun:

35%

Warranty:

1 year

Manual:

My Ratings

Build Quality

Usability

Ice Cream Quality

Value for money

Overall

Things I like and Things I don't

  • thumbs-o-up
    Makes good quality ice cream
  • thumbs-o-up
    Easy to use control panel
  • thumbs-o-up
    Small and light
  • thumbs-o-up
    It's very inexpensive!
  • thumbs-o-down
    Unknown brand
  • thumbs-o-down
    Doubts about long term durability?
  • thumbs-o-down
    Keep-cool feature is useless
  • thumbs-o-down
    1 year warranty only

On to the review. In my review of the Knox Automatic Ice Cream maker, I'll quickly look at how it works, I'll describe how to use it, I'll look at the quality of the ice cream it produces and finally I'll suggest some alternatives if it's not quite the right machine for you. 

How does the Knox Gear work?

The Knox Gear is a "compressor" ice cream maker. If you're not sure what this means, then I'll explain. There are 3 different types of ice cream maker. And the way they differ is in the way they freeze the ice cream...

  1. with ice and salt
  2. with a removable bowl that you pre-cool in your freezer
  3. with an in built compressor or freezer

So the Knox Gear has it's own, built in compressor that freezes the ice cream in the machine as it's being mixed. These compressor machines are the most convenient ice cream makers you can buy.

You don't need to pre-plan anything. There's no bowl taking up room in your freezer. When you want ice cream, you just turn the machine on to pre-cool, then add your mixture and within 40 minutes you've got ice cream!

However, compressor ice cream makers are much bigger, heavier and more delicate than the other types of machines. They're also more expensive. If you're not sure whether these are the right ones for you, check out my guide to choosing the best ice cream maker.

There are just 4 parts to the typical compressor ice cream maker and the Knox Gear is no exception. But you get a couple of accessories as well...

Knox Gear ice cream maker parts

The Knox Gear and all its parts

  1. the main body (which contains the compressor, the motor and the control panel)
  2. the bowl in which the ice cream is churned
  3. the paddle (or dasher) which mixes the ice cream
  4. a transparent plastic lid
  5. a spatula for scraping the ice cream out of the bowl
  6. a measuring cup

The body of the Knox Gear

The body of the Knox Gear is pretty light and compact for a compressor machine. In fact, it's the smallest and lightest ice cream maker with a built in freezer that I've ever tested!

Knox Gear ice cream maker front

The Knox Gear from the front

It measures 11" wide, 15.25" deep and 9.5" high (including the lid) (28 x 13.5 x 24 cm). And it weighs about 27 lbs (12 kg).

It features a very smart, stainless steel housing, with extensive air vents on both sides and decorative swooshes at both ends.

You must keep those air vents clear when the machine is churning, otherwise it won't cool properly. So the sides can't be pushed up too close to any walls. I'd recommend leaving at least 4" (10 cm) of space on either side of the machine.

Knox Gear ice cream maker side

The Knox Gear from the side

But luckily, the Knox Gear comes with a generous 60" (152 cm) power cable, which should give you loads of options when you're looking for somewhere to put it in your kitchen.

Knox Gear ice cream maker chamber

The Knox Gear compressor chamber

On top there's a big chamber with a metal bar sticking up from the center. This is where the bowl sits. The walls of this chamber are cooled by the compressor in order to freeze the ice cream mixture in the bowl. And the metal bar is turned by the motor, to rotate the dasher and churn the ice cream.

Knox Gear ice cream maker control panel

The Knox Gear control panel: simple but useful

In front of this chamber is the control panel of the Knox Gear. It's very simple, with just a small LCD display and 4 buttons:

  1. POWER
  2. TIME +
  3. TIME -
  4. START/STOP

The LCD display is clear and bright and will show you the time remaining, the temperature of the bowl and two symbols: one indicating that the compressor is on, the other indicating that the paddle is churning.

There's nothing fancy about this control panel. It's certainly not as feature packed as the Breville Smart Scoops but it's much more useful and user friendly than the Cuisinart ICE-100. The buttons work well. And the LCD display shows all the most important information.

The Knox Gear's removable bowl

The Knox Gear comes with a 1.5 quart (1.4 liter) anodized, aluminium bowl. There is hollow tube running up the middle of the bowl, through which the drive shaft slots when the bowl's placed in the machine. There's a thin wire handle in the bowl to hep you pull it out.

Knox Gear ice cream maker bowl

The Knox Gear bowl

As 1.5 quart bowls go, this is a pretty small one! For sure, it can hold 1.5 quarts of liquid but it comes right up to the top of the rim. This contrasts with the 1.5 quart bowls that come with the Cuisinart ICE-100 and the Smart Scoop which are much more generous, giving you a fair bit of excess space at the top of the bowl.

In practical terms, the Knox gear won't be able to produce quite as much ice cream as the other, bigger 1.5 quart machines!

These bowls are removable to make it easier to clean them, once you've removed the ice cream. However the bowl provides an extra layer of insulation from the compressor, so in theory the ice cream mix won't be cooled to the same extent as in the machines where there is no removable bowl.

The Knox Gears's dasher

The dasher is just a fancy name for the paddle that churns our ice cream. In this case, it's a simple all plastic thing with 2 blades.

Knox Gear ice cream maker dasher

The Knox Gear dasher is very similar to the Cuisinart ICE-100 gelato dasher

The dasher has 2 very important jobs:

  1. scraping frozen mixture from the sides of the bowl and moving it to the middle
  2. adding air to the mixture

These 2 jobs are so important because they have a huge influence on the quality and consistency of the final ice cream.

The dashers influence on the quality of the ice cream

Good quality ice cream is smooth ice cream. That's something we can all agree on. And we know from our ice cream science, that the faster the mixture freezes, the smoother the final product.

How fast the mixture freezes, is influenced by how close the blades of the dasher are to the sides of the bowl. On domestic ice cream makers there's always a gap. And that gap means there's always a thin layer of frozen mixture left on the sides.

Knox Gear ice cream maker dasher gap

The gap between the dasher blades and the bowl is tiny...

This layer insulates the rest of the mix from the coldness of the compressor. The bigger the gap, the thicker the layer and the more the rest of the mix is insulated. The more insulation, the slower the freezing, which results in larger ice crystals and less smooth ice cream.

Knox Gear ice cream maker insulating ice layer

... so the insulating layer of ice is really thin. 

Luckily the gap between the blades of the dasher and the bowl walls in the Knox Gear is tiny: less than 1 mm. So the mixture should freeze faster, producing smoother ice cream!

The dasher's influence on the consistency of the ice cream

The amount of air that the dasher adds to the mixture will have a profound effect on the consistency of the final ice cream. Lots of air produces a lighter, fluffier ice cream. Little air produces a denser, creamy ice cream.

How much air is added will depend on the speed and the shape of the dasher. However, all domestic ice cream makers spin much more slowly than commercial machines, so they whip low volumes of air into the mix to produce pretty dense ice creams.

The Knox Gear dasher spins at 56 rpm which is actually pretty fast for a domestic machine. So we'd expect it to whip slightly more air into the mixture than the competition and we'll find out exactly how much when we look at the quality of the ice cream it makes later on.

The Knox Gear's lid

The lid of the Knox Gear is a transparent plastic thing. It has a tiny, unhinged hatch for adding mix ins while the machine is churning.

Knox Gear ice cream maker lid

The lid of the Knox Gear ice cream maker

The hatch is held to the rest of the lid by a thin plastic chain (which I presume we're meant to remove and throw away?).

Knox Gear ice cream maker lid with hatch open

The lid with the tiny, strange hatch

But the hatch hole is far too small for adding mix-ins comfortably. I'm not sure why they didn't make it bigger!

The Knox Gear Accessories

You also get a small spatula and a measuring cup with the Knox Gear ice cream maker. The spatula is a nice size for extracting ice cream from the bowl.

Knox Gear ice cream maker spatula and cup

A spatula and a measuring cup: pretty useful!

And the measuring cup has ounces, cups and milliliter measurements on the side which I always find useful!


Making ice cream with the Knox Gear

Like every other ice cream maker, there's 5 stages to making ice cream with the Knox Gear...

  1. make the mixture
  2. pre-cool the machine
  3. churn and freeze the mixture in the Knox Gear
  4. transfer the ice cream to your freezer to harden
  5. clean the Knox Gear

Step 1: Make the mixture

Depending on your recipe, this stage can either be done while the Knox Gear is pre-cooling or well in advance...

If your recipe needs to be cooked, then it will need to cool down before you can put it in the machine. And that means you'll need to make it well in advance. However, if it doesn't need to be cooked, as long as the ingredients are all well chilled, it can go in the machine as soon as it's mixed.

The recipe you use here is really important. You can't throw any combination of milk, cream and sugar into the ice cream maker and expect it to pump out amazing ice cream. It's a very delicate and complicated substance and all the ingredients need to be in perfect balance, or it just won't work!

With this in mind, I'd advise you to start off with well known, tried and tested recipes before you start experimenting. Once you've found your feet with these, you can start to learn a bit about the science of ice cream and get crazy!

Jenis Splendid Ice Creams at Home cover

Jeni uses a really unusual egg-less base

The Knox Gear manual has several recipes you could try. Otherwise there are plenty of amazing ice cream recipes books. I've been having great success with the the recipes in Jenis Splendid Ice Cream at Home, Ices: The Definitive Guide and Gelato Messiana: The Recipes.

Gelato Messina: The Recipes cover

This is a great gelato recipe book

There's just two important things to remember here. Firstly, the Knox Gear has a small 1.5 quart capacity so you shouldn't be adding more than 1 quart (0.9 litres) of mixture. And secondly, you must make sure the mixture is chilled to at least fridge temperature before you add it the machine.

Step 2: Pre-cool the Knox Gear

You don't have to pre-cool your ice cream maker, but I highly recommend you do. As I've mentioned before, the faster you freeze the mixture, the smoother the final ice cream will be. And if you add your mixture to a bowl that's already super cold, it will freeze faster!

All you've got to do is put the bowl in the chamber, turn on the machine, set the timer and hit the START/STOP button. The compressor will start cooling and the dasher will start turning. Unfortunately you can't cool the machine without the gear turning. But it's no problem if the dasher turns in an empty bowl. Or, you could just run it without the dasher and then slip it on just before you add your mixture.

Knox Gear ice cream maker pre-cooling

Pre-cooling with the lid on helps reduce the temperature

One thing you don't want to do is let the timer run out while the machine is pre-cooling. If you do, the machine will automatically turn off and even if you start it up again immediately the compressor won't come on again for a good few minutes, during which time the bowl will warm up considerably.

With this in mind, you don't want the timer to run out before your ice creams done either, or it's going to start melting before it's ready! So always be generous with the timer. Personally, I leave it at 60 minutes. And after 15 minutes I come back to check the temperature.

Knox Gear ice cream maker pre-cool temperature

Pre-cooling: the temperature is down to -29°F (-34°C)!

The great thing about the Knox Gear is that it shows the current temperature of the freezer on the LCD display. After 15 to 20 minutes of pre-cooling with the lid on, the Knox Gear display will often read -29°F (-34°C). When I've checked it with an infrared thermometer, the bowl is actually closer to -18°F (-28°C). But this is still pretty impressive.

Step 3: Churn and freeze the mixture in the Knox Gear 

So now your ice cream mixture is pre-cooled in the fridge and the Knox Gear is pre-cooled on your counter top. It's time to make some ice cream!

As I alluded to in the previous section, it's really important that machine doesn't stop until your ice cream is ready to be removed. So before you add the mixture, make sure there's more than enough time left on the timer. Make sure the dasher's in the bowl and is rotating. Then just pour in the mix.

Knox Gear Ice Cream maker start churning

Knox Gear ice cream mixture just gone in

Now all domestic ice cream makers are loud. But they're no louder than a hairdryer. The Knox Gear is actually a bit noisier than some of the machines I've tested. At 79 - 83 db, your're not going to watch TV in the same room but it's certainly not unbearable.

How long it takes until your ice cream is ready to come out depends on several factors. Most importantly the recipe you're using, the temperature of the mixture and the temperature of the machine. It's going to vary, so you need to keep checking the consistency. 

Knox Gear ice cream after 15 minutes

Knox Gear ice cream after 15 minutes

The ice cream in a domestic machine will never get to the same hardness as the stuff you buy in the shop. What you're looking for is a soft serve type consistency, almost like thick, whipped cream, with the ice cream coming away from the sides of the bowl. Or you could just check the temperature. When it gets down to 21°F (-6°C) it's pretty much done.

Knox Gear ice cream after 30 minutes

Knox Gear ice cream after 30 minutes, just before it came out

However, if you can leave it in longer to get colder, all the better, as this will promote a smoother final texture. After 20 minutes this batch was down to 21°F (-6°C), but it was still churning well, so I left it in for another 10 minutes and it got down to 18°F (-8°C). After a total of 30 minutes it looked good and I could hear the motor straining a little so I took it out.

The Knox Gear dasher is looks very similar to the dashers that come with the Cuisinart machines (particularly the gelato dashers). However, I think the Knox Gear dasher is actually much better...

Both types of dasher really efficient so the mixture starts to freeze and thicken very quickly. But in the Cuisinart machines the ice cream will start to ride around on the dasher towards the end of churning so that it's not actually being mixed. While in the Knox Gear and other Foshan Nordika machines, the dasher continues to mix the ice cream throughout the churning cycle.

This enables us to keep mixing the ice cream in the Knox Gear (and other Foshan Nordika ice cream makers)  for longer and could lead to smoother ice creams.

If you run the machine until the timer reaches zero, the machine will automatically turn off. However, the Knox Gear does have an automatic keep-cool function. After 10 minutes, the compressor will start up again and will run for 10 minutes before turning off again. This cycle will keep repeating for up to an hour, when the machine will finally turn off for good.

However, I'm not very keen on this feature as a huge amount of melting can go on in 10 minutes, and then when it's re-frozen in the next 10 minutes, the quality of the ice cream will really suffer.

Step 4: Transferring the ice cream from the Knox Gear to the freezer

Once you're happy with the final consistency or temperature of the ice cream, it's time to get it out of the machine and into your freezer. Again, you don't have to do this. You could just eat it straight from the machine.

But it's not properly frozen yet. And although it will taste pretty fantastic, it'll melt incredibly quickly. It's much better to control yourself and stick it in the freezer for a couple of hours at least!

The trick here is to do it as quickly and coldly as possible. Any ice cream that melts during the transfer will re-freeze in the freezer causing the existing ice crystals to grow and become more detectable on the tongue.

Knox Gear transferring the ice cream to the freezer

Transferring the ice cream to the freezer: be quick!

So, make sure you the container you're going to put the ice cream in is really cold. I like to use wide, shallow dishes that are made of glass or metal as these encourage fast freezing. And I'll put them in them freezer to pre-cool while the ice cream is churning.

Remove the bowl from the machine and scrape the ice cream into the container as quickly as possible. Then place a layer of clingfilm or baking paper on the surface of the ice cream (this will prevent ice crystals forming on the surface), get the lid on and put the container in the coldest part of your freezer.

It will usually take between 2 and 3 hours to firm up to the consistency you want. Don't check every 10 minutes though as it will slow the whole process down and compromise the texture!

Step 5: Cleaning the Knox Gear

Thankfully this is is really easy. The bowl, the dasher and the lid can be washed very quickly in warm soapy water. The good thing about compressor ice cream makers is that the bowl warms up really fast, so any ice cream frozen to the sides melts really fast too and can be easily cleaned away. None of the parts are dishwasher safe but they're so easy to clean, it's really not an issue.

Knox Gear time to clean up

Time to clean up!

The body of the Knox Gear usually just needs a quick wipe down with a wet cloth. You need to be careful that there's no mix left in any crevices, as this will go rancid. And as with all these machines, the stainless steel is not really stainless and you'll be left with water marks that are hard to shift!


How good is the ice cream from the Knox Gear?

For such a small, cheap machine the Knox Gear makes surprisingly good ice cream, gelato, frozen yogurt and sorbet!

The overrun from 800 ml of no-cook ice cream mixture was 35%, which is more or less average for a domestic machine. But it's quite low compared to most store bought stuff. So you get a nice dense ice cream.

As we know, the speed at which the mixture is frozen has a significant impact on the smoothness of the final ice cream. And with the Knox Gear able to reduce the temperature of the bowl to a very impressive -18°F (-28°C), the tiny gap between the dasher and the bowl walls and the relatively high number of dasher rotations per minute (56), this machine was always likely to freeze the ice cream quickly.

And in fact the Knox Gear does seem to produce smoother ice cream than many of it's more expensive competitors!

Wrapping Up

The Knox Gear has surprised me to be honest. I think it's great little machine that does many things right. However, it won't be for everyone. So here's 3 things I love about it and 3 things I'm not so keen on.

3 things I love about the Knox Gear Ice Cream Maker

1. It's small

This is one of the smallest compressor ice cream makers currently available. In fact, it's not much bigger than an a freezable bowl machine, which is incredible really when you think that they've got to fit a compressor in the body too.

2. It's fast 

The powerful compressor and the efficient dasher mean that the Knox Gear makes ice cream fast! It's not unusual for me to be extracting the ice cream from the machine after 20 minutes.

3. It's really cheap!

The Knox Gear is one of the cheapest compressor ice cream makers currently available. To be honest, I'm not sure how they're able to sell it so cheaply and still make a profit. But they are at the moment and I think it's a bargain.

3 things I don't like about the Knox Gear

1. The Knox Gear brand is unknown

Knox Gear is a new and untested brand. This makes me slightly nervous. Not because I have doubts about the build quality of the ice cream maker, since they don't actually make this ice cream machine! I'm more worried about how long they'll be around for and how they'll deal with things if something does go wrong.

2. Doubts about the build quality?

I've read several reviews from people who've had this ice cream maker for longer than I have and who claim it just stopped working. Now to me the build quality seems good. Foshan Nodika, the company that actually manufacture this machine has a lot of experience and knows what they're doing. And all compressor machines can just stop working: they're delicate. But I should mention it, because it may be an issue for some.

3. It has basic functionality

You don't get any of the bells and whistles you get with the Breville Smart Scoop. There's no automatic pre-cool, pre-programmed hardness settings or intelligent keep-cool. This is a basic machine that you'll need to monitor while you're using it.

Alternatives to the Knox Gear Ice Cream Maker

If you're thinking that maybe the Knox Gear isn't the right ice cream maker for you, then don't fear as there's loads of alternatives. I recommend two good ones below...

Looking for a more automated experience?

If the Knox Gear is just too hands-on then take a look at the Breville Smart Scoop. The Smart Scoop tries really hard to take all the guess work out of ice cream making.

Breville Smart Scoop bci600xl with mixture

Pre-cooling is automatic. You just press the special pre-cool button, sit back and wait. The Smart Scoop will cool the bowl to the optimal temperature and then ding to let you know it's the right time to add your mixture. It will even start rotating the dasher towards the end of the pre-cool, just in case you decided to pre-cool the mixture too! 

The Smart Scoop will also decide when your ice cream, gelato, frozen yogurt or sorbet is ready. Simply choose from one of twelve hardness settings that correspond to the type of desert you want to make. The Smart Scoop will start freezing and churning the mixture and when it reaches your desired consistency it automatically turns off.

There is also an intelligent keep cool function, where once the cycle has finished, at intermittent times the it will test the consistency of the ice cream and if the machine finds it has melted beyond a certain point, it will begin churning and freezing again. In this way it can keep the finished dessert at the desired consistency for u to 3 hours.

This functionality doesn't come cheap though. The Smart Scoop is more than twice the price of the Knox Gear. But if you're looking for a fully automated service and exceptional build quality from a well established brand then it's worth looking at.

Looking for something more reliable?

I don't think the Cuisinart ICE-100 is built any better than the Knox Gear ice cream maker. And in fact, the control panel on the Knox Gear is far superior to the one on the Cuisinart machine!

Cuisinart ICE-100 with gelato

But Cuisinart is a well established and highly respected brand that you know will still be operating in 25 years time. What's more, the ICE-100 comes with a nice 3 year warranty.

Having said that, the ICE-100 doesn't make ice cream that's noticeably better than the Knox Gear but it is significantly more expensive! And you can always take out extra cover on the Knox Gear for a very low fee.

So maybe the Cuisinart ICE-100 is not such a good alternative in this case!

Conclusion

The Knox Gear Automatic Ice Cream Maker, is a fantastic, little budget machine. The functionality is pretty basic. But what it does do, it does really well.

The control panel is easy to use and the display panel shows you everything you need to know, including the temperature of the bowl.

The powerful compressor is able to chill the bowl to a very impressive -31°F (-35°C) and the relatively fast rotating dasher leaves very little ice on the sides of the bowl. This means that the ice cream is frozen very quickly and is pretty smooth.

And the price is fantastic. What's not to like?

Well, Knox Gear is an unknown brand, some people have raised doubts about it's reliability and it only comes with a 1 year warranty.

But you know what, if it suits your budget and has everything your looking for then I think it's a good buy. And if you also buy the 4 year protection from Amazon, which will cover any faults and shipping both ways you're totally covered if anything goes wrong!

Knox Gear Specs

Width:

11"

Height:

9.5"

Depth:

15.25"

Weight:

27 lb

Loudness:

79-83 Db

Paddle Rpm:

56

Overrun:

35%

Warranty:

1 year

Manual:

My Ratings

Build Quality

Usability

Ice Cream Quality

Value for money

Overall

Things I like and Things I don't

  • thumbs-o-up
    Makes good quality ice cream
  • thumbs-o-up
    Easy to use control panel
  • thumbs-o-up
    Small and light
  • thumbs-o-up
    It's very inexpensive!
  • thumbs-o-down
    Unknown brand
  • thumbs-o-down
    Doubts about long term durability?
  • thumbs-o-down
    Keep-cool feature is useless
  • thumbs-o-down
    1 year warranty only
Summary
Review Date
Reviewed Item
Knox Gear Ice Cream Maker
Author Rating
51star1star1star1star1star
Click Here to Leave a Comment Below 22 comments
John Robie - October 31, 2017

Couple of comments about the Knox ICM.

1. A splash of antifreeze (e.g. Vodka or Isopropyl Alcohol) in the base reduces the differential temperature between the container and the base and results in considerably faster freezing. I have a 40F difference without the antifreeze and a 20F difference with it. This almost halves my freezing time. I’d be interested to hear how it works on your machine.

2. The only temperature range where ice crystals can form is between 32F and 23F so prechilling in the fridge doesn’t matter. There might be a tiny thermal kick by letting the innards of the Knox get down to -22F. But if the mix is at 40F when going into the Knox then the kick will be lowering the temperature in a range (40F to say 38F) where ice crystals aren’t forming so what’s the benefit? The only case where the kick can help is when the mix is exactly at 32F going into the Knox and that requires putting the mix in a freezer and monitoring. IMO the time involved in prechilling can be eliminated. I put the mix right into the churning bowl from the blender and let the Knox do its thing.

If my reasoning has holes in it I’m all ears!

This comment probably belongs in the Ice Cream Science section – and/or the Knox review.

Cheers,
John

Reply
    John Robie - October 31, 2017

    One other comment about the Knox. Stalling the paddle only adds 10 watts of power consumption and doesn’t in any way harm the machine. I let the paddle stall since I want the thickest possible result.

    Pull the cover off the bottom and look at the way it’s set up. No worries.

    Reply
    Carl - November 2, 2017

    Hi John,

    1) Do you mean adding antifreeze between the bowl and the cavity that the bowl sits in?

    2) The ice crystals don’t form uni-formally throughout the mixture. They form on the sides of the bowl. So if we don’t pre-chill the mixture in the fridge, there will be a bigger difference in temperature between the mixture at the colder sides of the bowl and the mixture in the middle of the bowl.

    And when the ice crystals from the sides of the bowl and are then moved into the middle of the bowl by the dasher, more of them are going to melt for longer because the mixture is warmer. I write about this process here.

    I think it’s this extended period of melting, while those ice crystals cool down the middle of the mixture that’s the issue here. The more protracted this stage, the more melting and re-freezing, and the bigger the ice crystals. I think!

    Thanks

    Carl

    Reply
John Robie - November 7, 2017

“1) Do you mean adding antifreeze between the bowl and the cavity that the bowl sits in?”

Yes. I notice that on second column of page 41 of “Ices, the Definitive Guide,” the authors say, “and this requires the addition of a salt or alcohol solution to create a seal between the bowls.”

I don’t completely follow your reasoning about the ice crystals but I have confirmed that I cannot detect any difference between prechilled and 70F mix except the length of time required to freeze it. They both produce gelato consistency with no detectable iciness following your “perfect” recipe. It is that, by the way. I’m addicted.

When using alcohol as a seal I can stall the paddle in about twenty minutes using a 70F mixture in a machine that has not been prechilled. It takes quite a bit longer without the alcohol. The Knox temperature display goes to about -2F and stays there until the paddle stalls upon which it drops to about -4F. The paddle stalls at an ice cream temp of about 21F.

I also find that briefly (5 seconds or so) dipping the finished ice cream bowl in 70F water and sliding the scoop to the bottom along one side to allow air in lets me slide out the paddle and ice cream in one piece. This is much easier than digging all the ice cream out with a spatula.

I dump them into a prefrozen ICE-21 bucket, scrape the paddle clean and then stir for a minute or so. This produces a good consistency immediately.

I afforded myself the luxury of an inexpensive one cubic foot freezer that I shall set for 4F – this will let me store the ice cream at a ready to eat temperature. Prior to transfer I’ll keep the the ICE-21 bucket in the main freezer so I get the benefit of extra freezing power when I transfer ice cream from the Knox bucket. Then I’ll store the ICE-21 bucket in the ice cream freezer. Freezer arrives today.

Not having a 4080 I can’t compare but I would be interested in knowing if you find using the Knox with an alcohol seal and waiting for the paddle to stall produces the same quality result as the 4080.

Cheers,
John

Reply
    Carl - November 9, 2017

    Some great tips there John!

    Yes, I remember people talking about the alcohol seal before. I wonder why it stopped being a thing to do? I’ll give it a go and report back.

    In my Knox Gear, without the alcohol, after pre-cooling (but before I add the mixture) the temperature display shows -27 F (-33 C), although when I measure the real temperature of the bowl with an infrared thermometer it reads -18 F (-28 C).

    Then, once the mixture is added, the display varies between -27 and -28 (-17 and -19 C) throughout the churning process. I usually stop after 20 to 25 minutes when the paddle starts to struggle a bit and the ice cream temperature is around 21 F (-6 C).

    I dream about having a separate freezer for my ice creams where I can regulate the temperature! I’m sure that will make a big difference, as it won’t go through that cycle or melting and re-freezing to soften it every time you want a scoop.

    I’ll try your tips and get back to you. But I’m pretty sure the ice cream won’t match the Lello for smoothness!

    Reply
      John Robie - November 14, 2017

      I added 2 grams of powdered lecithin to your “perfect” recipe and it seems to make it less icy at freezer temp. Makes sense since that’s the main emulsifier in egg yolks.

      When I do a half recipe and start with mix at 40F and a pre-chilled machine the paddle stalls in less than ten minutes! That’s a pretty fast freeze!

      It may seem a bit counter intuitive but the -28F you are seeing indicates that the differential temperature between the coils and the mixture is much too high. The object is to pump the heat out of the mixture as fast as possible so you want to achieve lowest differential temperature you can get. Ideally one would like to see a temperature display of about 21F though that’s never gonna happen. I get -2 to -7 so I’m actually pumping an additional 20 watts of heat over the normal 60 watts without the alcohol. I see 100 watts of consumption without the alcohol and 120 watts with it. That’s without the dasher turning and with a tub filled with room temperature water. I’m assuming that 40 watts of that 100 watts is waste heat that comes from driving the compressor.

      It’s easy to make the mistake of thinking that the coldest reading the machine can muster indicates its cooling power. Not so. To measure the cooling power you can fill the container with a liter of water at (say) 20C and measure how long it takes for it to drop to 10C with the dasher turning. This is a simple and infallible test of cooling power and can be conducted on any compressor type machine. Don’t pre-chill because the object is to measure the steady state heat pumping power.

      I don’t know if you’re interested in these kinds of technical details but if so I can provide more information. Right now I appear to be getting much faster freeze times than what people report for the Lello 4080 so I must be doing something right!

      Most interested in hearing how well the Knox w/ alcohol seal fares against the 4080. Just to be clear, I pour about 7.5gm of 50% (70% will work fine) isopropyl alcohol in the base of the Knox and slowly lower the ice cream tub into the machine. Overfilling can cause alcohol to come burbling up the center shaft and it seems to have dissolved the silicon seal that keeps ice cream from dripping down the drive shaft into the bottom of my machine. I replaced the missing seal with some O-rings to fix the problem. The alcohol spill washed away some shaft lubricant and that caused the shaft to squeal a bit. I just took off the bottom panel, pulled the shaft out and relubed it with some silicon grease. Just remove the timing belt and the shaft comes out.

      I have a strong technical and engineering background so I’m right at home taking this kind of stuff apart. If you ever need some O-rings just let me know and I post some over to you. The work just as well as the original seal.

      I think the Knox unit is well designed. I stand by my advice that absolutely no harm comes from letting the dasher stall. The stalled low torque inductive drive motor will not overheat or strain the gear train. As I said before, the additional electrical load when stalled is less than ten watts. The torque of the motor actually diminishes when stalled. You can verify this by stalling it by hand. There is no clutch to wear out. Perfectly safe.

      I’m gonna get fat!!!

      Cheers,
      John

      Reply
        John Robie - November 14, 2017

        P.S. 80 or 100 proof vodka will work as well as isopropyl alcohol and is less toxic for those concerned about it getting into the ice cream.

        Reply
        Carl - November 15, 2017

        Yes adding Lecithin makes sense. I’ve got some in the cupboard so I could try it. But I want to limit the recipe ingredients to “supermarket staples” as much as possible.

        I think my original suggestion that the condensed milk was controlling the ice crystals to some extent, was wrong. I think it contains the wrong type pf sugar.

        Karo Light corn syrup is the right sort of sugar though, so I might try replacing some of the evaporated milk with that. Too much will add a really unpleasant taste to the ice cream though!

        I’ll do a side by side comparison between the Lello 4080 and the Knox next week and let you know how it goes!

        Reply
          John Robie - November 16, 2017

          I purchased lecithin on Amazon – a pound sells for $13US and that’s over 4000 batches at 2 mg. I just need to remember to freeze most of it since at room temp it sucks moisture out of the air and gets all gummy.

          Nowadays Amazon IS the supermarket. You might have the recipe with two endings, one with lecithin and one without. I’ll never go back to not using it I’m sure. I did a batch without lecithin today by mistake and it was much icier at 8F. Just redid a second batch with lecithin – much much better.

          I have some Karo corn syrup so I’ll try that as a substitute for some of the condensed milk though I rather like the flavor the condensed milk imparts.

          I think you probably intended this to be in the recipe section rather than in the Knox review.

          Reply
          John Robie - November 16, 2017

          It would be hard to accept that a $150 machine is making ice cream as good as or better than a $700 machine. That’s a great target for confirmation bias! The Lello may have a bit huskier dasher motor but I have a hard time believing its compressor is stronger. If it were the freeze time would be appreciably shorter. And I have absolutely no faith in Italian engineering – I’ll take Chinese over Italian always. Not that the Lello is bad but it doesn’t appear to have changed in a decade.

          The dasher looks like it’s a lot more fun to lick off – I’ll give it that! I hate licking the Knox dasher. Too many nooks and crannies.

          Reply
          Carl - November 16, 2017

          Yes, as I say in the review, I was dubious about the Lello right up until the first time I stopped the dasher and dug the spatula into the ice cream! And there’s no doubt in my mind that it makes the smoothest ice cream I’ve had by far. Maybe it’s the speed, sharpness and power of the blade?

          As I say, I’ll try your tips and film a side by side comparison next weekend to be sure.

          However, the Knox Gear is certainly the best value compressor machine about. Bearing in mind that the unit price from Foshan Nordica seems to be $97, I’m not sure how Knox Gear are able to turn a profit at $160.

          Reply
          John - November 18, 2017

          I got mine for $134 including free shipping from Amazon. Perhaps the $97 price you see is for smaller quantities. The Whynter sells for $270 and appears to be very similar to the Knox. The bucket and dasher look identical. I would imagine the drive system and compressor are the same as well.

          I don’t know how the Lello does it and I’m not going to spend $700+ to find out! That’s why I’m hoping you can do some reasonably objective comparisons.

          With the addition of lecithin to your “perfect” recipe I’m totally pleased with the Knox. I’m eating firm ice cream less than 30 minutes from turning on the compressor. 10 minutes of cool down while I mix the ingredients and 15 minutes of churn to stall the dasher. 5 minutes to transfer to the prefrozen ICE-21 bucket. Then it’s yum time.

          Reply
John - November 18, 2017

I think a “fair” way to conduct the test would be to churn the ice cream in the two machines from the same batch of mix and transfer the two samples to two identical freezer containers and let both freeze to a temp of 8F. Then perform the taste test. I think the Lello may have a stronger dasher drive which lets the ice cream continue freezing under motion longer than the other brands. I suspect the Lello secret is in the stirring and that’s what keeps the ice crystals small. I hope you have enough confidence in my analysis of the Knox drive system to let it continue to a full stall since that’s the way it can do its best work.

I bought some Dreyer’s Coffee Ice Cream (which used to be a favorite) tonight and I’m letting melt completely. Tomorrow I’ll refreeze it and see how that goes. It’s interesting that I used to really like their coffee flavor. Now it tastes like garbage. I’ve gotten used to the clean light vanilla flavor of your recipe. Store bought ice cream is so sickeningly sweet — ugh. And the aftertaste is pretty bad too.

I’ve tried Ben and Jerry’s but they use too much sugar and it’s impossible to buy a simple vanilla – all their varieties are filled with cookies and candy and this and that. Hagen Daas (sp?) Vanilla was icy, thin and totally blah.

It’s grand to have control of the recipe and the sugar content. I bought some maltodextrin and intend to try using it as a partial substitute for sucrose to reduce sweetness even further. I bought a second ICE-21 bucket so I can make two small batches in one session and quickly have samples ready to taste.

As a total aside, my spell checker just suggested “extramarital” as a replacement for “maltodextrin”!!! Lord help us if that’s AI at work.

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John - November 18, 2017

What is the draw temperature of the 4080 “perfect” ice cream? I get a reading of about 21F for the Knox. If the Lello’s superiority is due to a stronger dasher torque, that would show up as a lower draw temperature since it can continue to cool longer under motion. Temperature drops in this range are nonlinear because the mix is undergoing a phase change from liquid to solid. It’s a messier process than for water since various components of the mix freeze at different temps. Still, the temperature drop will be quite gradual until around 18F whereupon most of the mix is frozen. I believe about 60% is frozen at 21F so there’s still a lot of unfrozen mix. If you are seeing a 4080 draw temp of 18F or lower that’s a strong argument for the “beefy dasher motor” being the main reason the 4080 produces such creamy texture.

My strong hunch is that you’ll observe an 18F finish. If so then there’s really nothing to do to improve the other machines because their plastic dashers wouldn’t withstand the high torque of the 4080 drive motor. It would be difficult if not impossible to manufacture an inexpensive food grade high torque dasher. That 4080 stainless steel dasher is probably one of the the most expensive parts of the 4080. That’s assuming, of course, that the dasher isn’t produced by a third party for a number of designs. There are a lot of commercial ice cream machines out there.

It’s completely understandable why ice cream that’s 40% unfrozen upon draw will produce an icier result than a mix that’s only 10% unfrozen. I’m predicating all this on the belief that all freezing under motion results in tiny crystals. And that’s really the only thing the 4080 can do better than the other machines. It doesn’t freeze faster so what else is there? I’m thinking that the speed of freezing is much less important than achieving the lowest possible draw temperature. I can test this idea by drawing samples from the Knox at various temps and smearing them on the side of an ICE-21 bucket for quick static freezing. I plan to standardize on 8F as a sampling temperature (that’s the warmest setting on my Igloo 1 cu. ft. ice cream freezer.

Cheers

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    Carl - December 12, 2017

    Yep, it’s not working like it used to unfortunately.

    The compressor cools down normally. But once the mixture’s in and the motor has to work a bit, one side of the machine starts to warm up and after about 15 minutes and it becomes hot to touch.

    Eventually, I think the heat starts to impede the compressor and the temperature rises.

    I can get ice cream out of it. But it’s not a patch on the first few time I used it.

    Any suggestions?

    Reply
      John - February 19, 2018

      Check to see if the fan is blowing air. Your fan motor may be frozen up. See comment below for more info.

      Reply
John - November 18, 2017

I thought about it a little more and realized that the plastic dashers have a serious additional problem – flexibility. As a frozen layer builds up on the wall it presses the blade of the dasher inward. Since the dasher is a plastic blade there is considerable movement possible and this allows the thickness of the ice cream on the wall to become considerably more than what one measures when the blade is in an empty bucket. Again, the 4080 would not have this problem since there is no flex in the stainless dasher.

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    Carl - November 25, 2017

    Well, I just ran the Lello and the Knox Gear in a head to head and it turned into a bit of a disaster!

    I was using a new mixture which is a (no-cook) variation on Dana Cree’s Philadelphia base. One preparation divided between the two machines.

    The Knox Gear pre-cooled as usual, showing -26 F (-32 C) on the screen. But once I’d added the mixtures, after 15 minutes I noticed that in the Knox Gear it wasn’t thickening up. And the temperature on the screen was increasing, going from 12 F (-11 C) when I first checked, up to 18 F (-8 C) when I finally decided to turn it off.

    And the reason I turned it off was that the left hand side had become incredibly hot. To the extent that it was difficult to touch!

    I’m hoping that this was just because I’d placed the two machines too close to each other, with the side vents facing each other, rather than an internal problem. Maybe the Knox Gear was drawing in hot air from the Lello?

    Anyway, I’ll try it again in the week when I can get some more ingredients. I hope it’s not a permanent issue!

    Reply
      John - February 19, 2018

      Well, my Knox just went into the dumpster. It developed a refrigerant leak in the aluminum tubes that wrap the freezer bowl. Recharging didn’t help – the pressure dropped in just a few days. I’m guessing that the aluminum tubing had a hairline crack that eventually got worse. The tubing is foamed in place and can’t be accessed. Even if I could get to it I wouldn’t be able to repair a crack. I’m pretty handy at repairing things but this one was beyond me.

      I also noticed from the teardown pictures of the ICE-21 on icecreamscience.com that it is clearly made by the same company that makes the Knox – Foshan Nordika or whatever.

      Once burned twice shy.

      Regarding your problem with the Knox overheating, did you check to see if the fan that blows air across the condenser coils was working? It’s hard to understand why those coils should get piping hot if the fan is operating correctly.

      The bearings in the drive motor of my Knox were dry – not a trace of lubricant. That could also be the case with the fan motor. You can oil it with a bit of sewing machine oil.

      Getting the case off is a bit tricky. There are 8 screws running around the edge. Remove those and the fiddle around until the two snap latches on each side in the middle of the long dimension release. There’s no clear way to get them to break loose other than wiggling and wriggling until they pop. I cut them off afterward because they’re in no way necessary.

      Knox Gear is no longer listing this model on Amazon US. I think it’s dead meat. I’d never buy another one. The manufacturing date of mine was Jan 2016 so the charge held for two years and then a leak developed. I don’t trust aluminum cooling coils.

      I’m of the opinion at this point that all these compressor units save perhaps the 4080 are pretty much a crap shoot. I’m better off with a freezer bowl unit. It’s a lot cheaper and my freezer is very reliable. It’s been running for twenty three years.

      Reply
John - February 19, 2018

One other thing. When you finally break the cover loose from the base you’ll find a cable connector that appears to have a locking latch. It does not! Just pull on it hard and it will come apart. I must have spent ten minutes trying to find a way to “unlatch” it by pushing on those serrated wings that stick out from the sides. Once the connector is loose you can remove the cover. The tie wraps that hold the cable inside the cover can also be removed. They’re worthless.

I think you’re going to find the little fan that sits in the cowl has frozen up. Just squirt some oil on the front and rear bearings and it should free up.

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    Carl - February 20, 2018

    It’s already gone back to the vendor for repair or replacement John!

    Reply
      John - February 20, 2018

      I just made a batch of your recipe using an ICE-21. Works much better than the Knox ever did. Mix went in at 40F and I pulled it at 17F. The bucket was still gurgle free. Paddle is much easier to clean. The Knox dasher would stall at 22F and I had to transfer to a frozen Cuisinart bucket and finish it by hand.

      You might want to let readers know that the 3 year US warranty for the Cuisinart ICE-100 requires the customer to pay shipping costs both ways and the cost of shipping 40 pounds to the East Coast from California comes to almost $100. Lots of Amazon reviewers are upset by this and I would be too. So, yes, it’s a long warranty period but it can still cost nearly half the price of the unit to pay for shipping.

      And I believe the ICE-100 is a relabeled Foshan Nordika machine. I am no longer a fan of that company. After reading a lot of negative reviews on all their models (including the ICE-100) I concluded that their quality control on the cooling bucket is lousy. LOTS of people complaining about brand new units that didn’t get cold after half an hour. This is almost always caused by loss of refrigerant. Foshan Nordika buys the refrigerator compressor and condenser from a company that mass produces them but the build their own freezer buckets. It’s devilishly difficult to do quality control on aluminum tubes bent at sharp radii.

      The buckets aren’t made by the millions like the compressors and condensers so there’s no money to build highly reliable test fixtures like there is for the compressors and condensers. Even if they did, initially a bucket could test leak free. However, small fractures can take a year or more of stress before starting to leak enough to be detectable. I suspect it’s the constant temperature cycling that causes the small defects to eventually turn into large leaks. And, as I mentioned before, there is absolutely no way to fix them.

      Furthermore, these machines are manufactured very cheaply. We know they can sell them on Alibaba for under a hundred bucks.

      The 4080 engineers were probably thinking of this when they decided to only wrap cooling pipe around the outside walls. While the forsake about 1/3rd of the total cooling area, it lets the coils be bent gently on a large radius. It may also be that the 4080 uses copper cooling tubes though I doubt it given the high side/low side pressure specs.

      I won’t get another compressor machine. No reason, considering how little ice cream I make. $45 for an ICE-21 and $80 for a small freezer is a lot cheaper than the cheapest compressor model. And it will work for a long time. I don’t make batches in rapid succession so there’s no reason to have one. Even if I did it would be cheaper to buy an additional bucket.

      Reply

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