Soon after I started to make my own ice cream at home I realised that I need to find out more about the process of ice cream making to make sure that my ice cream is as good as the one from the shop. One of the main problems I’ve come across is an ice cream crystallising when you want it to be nice and smooth.
I don’t have an ice machine or churner, so I make everything by hand and using an electrical hand held whisk. If you have a proper ice cream machine, you probably won’t have much problem with the crystallisation, but if like me you only have basic equipment, you might like to carry on reading.
So, what causes an ice cream to crystalise?
Lets rewind a bit first…
If you made your ice cream and simply froze it, you’d end up with a solid lump of ice cream. But, if you don’t allow the water to freeze undisturbed (i.e. you whisk it or churn it) you break the frozen crystals of water until those crystals are so tiny, you can’t even see them or feel them.
So, the trick is to cut up, whisk or churn those water crystals until they are so small they don’t even freeze closely together.
This is why you need to constantly churn your ice cream or whisk the ice cream in regular intervals and don’t allow the ice cream to set until the right smoothness is achieved.
If you stop too soon, those crystals will start to grow again in your ice cream and you’ll end up with gritty ice cream.
Another thing that’s worth mentioning is that the more fat you have in your ice cream the less water you have (naturally), which means that you can achieve much smoother ice cream.
This is worth knowing, when you are making a sorbet, because it really need to break down those frozen water crystals and don’t let them to form.
Ingredients that help you to achieve a smooth ice cream
When you are making a sorbet
Glucose is a form of sugar, that looks like a see through glue. It’s mildly sweet, but it doesn’t really taste of anything. Just one table spoon of glucose is going to make a big difference to the smoothness of your sorbet. Glucose can be used with any flavour, as it won’t impact on the overall taste.
Can be used in dairy ice cream, but the egg yolks and cream are usually enough to add the smoothes you need.
Corn Syrup/Honey/Golden Syrup
Similar uses to glucose, but with a flavour and a specific taste. Be careful how you use these as not everything will work with your ice cream.
When you are making a Dairy Ice Cream
The fat in the milk is what makes your ice cream smooth, rich and creamy. Whilst you can make ice cream with just a skimmed milk, using a full fat milk, cream or butter cream is going to dramatically change the way your ice cream taste.
A lot of modern ice cream recipes don’t use eggs or use less of them, but the traditional ice cream recipes use a lot of egg yolks. This is because egg yolks have a lot of protein and fat and help to emulsify the water in the ice cream, making the mixture beautifully smooth.
Egg yolks also add flavour and colour and since traditional ice cream was usually vanilla flavoured, you can understand how the huge amount of yolks helped to create the most amazing ice cream.
Extra tips on stopping crystalisation
Once your ice cream is done, freeze it as quickly as possible. The longer the ice cream takes to properly freeze, the more chances it has to develop further crystals (even when you took a good care to churn everything for as long as possible).
In domestic settings, this usually means putting the ice cream into a shallow container as this would make the ice cream to freeze a lot quicker.
You could also try to use the deep freeze shelf if you have one in your freezer or temporarily override your freezer temperature from -18C to say -22 C. Just make sure that you switch it down again after you’ve turned down.