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 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). 🙁
