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 too 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). 🙁
Have you tried a new recipe?
Did you get a good and creamy gelato?
Cheers
What do you think that the pros have that you don’t? I eat a lot of Gelato and it stores well in my very cold freezer. I need to know the trick as I want to make and sell it.
I think this is the downside that gelato makers/batch freezer makers don’t tell you. Yes, gelato tastes delicious out of the batch freezer and looks pretty in the display case. They tell you about the lower butterfat (ie more healthy) and lower overrun. But true gelato is meant to be sold as a fresh product. It doesn’t store well for long periods vs ice cream.
To compensate for higher water content, you need more sugar or stabilizers. It would be interesting to ask a professional gelato maker how long they can keep their product/inventory before they have to throw it out.
Yep this is very true Henry. Gelato doesn’t keep well, especially when its stored at the temperatures of our home freezers.
I make gelato and can keep it for days at home. What I Idid was buy a small freezer (2 cu ft) and Replaced the temp control with a PID controller that let’s me set the temp to 10 degrees F. At that temp my gelato lasts for days without turning into an icy brick.
The nice thing about the PID is I can set the temp to -50F on up which turns the freezer into what I call a freezerator, part freezer and part refrigerator depending on the temp.
Brilliant! I was thinking about doing this myself. But it seemed a bit complicated.
Then I saw these travel fridge/freezers on Amazon that had a wide range of temp settings. So I was also thinking about buying one of those but some some reviews suggesting they’re a bit unreliable.
Was it difficult to make the conversion?
No, it wasn’t difficult and the PID controller can be bought for around $35 US.
There’s plenty of YouTube videos that will take you through the steps.
Hi,
Love your website and your experiments!
I´m also a great gelato fan.
From what I have learned you wan´t the fastest freezing possible. At around -20 degrees the ice crystals almost stops growing completely. When setting your freezer at -15 degrees, you will probably get a very icy gelato. Did you have these problems? The big amount of dextrose lowers the freezing point a lot, which should increase iciness even more.
To try to minimize risks of iciness I´m doing quite the opposite from you. I have set my freezer to its lowest temperature (-23 degrees). It takes around 2 hours in the freezer to reach -12 degrees, which is a good serving temperature according to me.
The gelato that gets left over I want to be frozen to the lowest temperature possible as soon as possible. I have not experienced any problems with tawing deep frozen gelato. I put it in the fridge around 30 minutes before serving. Works perfect, although not quite as good as freshly made.
Best regards,
Jacob
Hi Jacob,
Yes this is sort of how commercial operations work. In the hardening stage they get the gelato down to -35 degrees (where ice crystals will stop growing). Then they take it out and it warms to serving temperature.
The problem is, if we keep taking it out to warm and then putting it back to freeze, it’s going to get increasingly icy isn’t it?
I haven’t been working on this recently but there is a poster here that has rigged a small freezer up with a PID so it stays at a higher temperature, and he’s having success with that.
I might try the same
Cheers!
Carl
Yes, I’m the one who used a PID controller to set my gelato temp to 10°F and it works well. I’ve now set it to 8°F since the PID fluctuates +- 2 degrees.
When I remove the gelato from the frig I let it sit till it reaches 12°F but am experimenting with letting it sit till it reaches 17°F. The question is do I have the patience! 😉
Hi Carl,
I guess in this case it will be better to store the gelato in small containers, so you remove from the coldest temperature freezer only what you know you are going to consume, without refreezing the leftovers. It is a little bit annoying but unfortunately nothing comes easy if you want good results.
I will try to set my freezer to the coldest setting and check if this might give better results.
Yes, that’s a good point and a good tactic Paola!