Ice cream with 2 ingredients? Real ice cream? Yes, it really is ice cream and it really is just two ingredients (cream + condensed milk). It shows how easy cooking (and ice cream making) can be. All you need besides two those ingredients are a bowl, a whisk, a container and a freezer.
It so happens that this recipe is also great to explain the science of ice cream. The easier the recipe, the easier it is to extract the science without being distracted by all sorts of extra ingredients and process steps. We can properly zoom in on the role of all (in this case just 2) ingredients and see how these two ingredients fulfill all the different roles within an ice cream.
What is ice cream again (from a scientist’s perspective)?
When we talk about ice cream on this blog we tend to talk about a creamy ice cream, generally scooped in balls onto a cone or in a cup. As opposed to popsicles (which are essentially frozen lemonade), these ice creams contain fats, sugars, often proteins, water and most importantly air!
A more ‘scientific’ analysis of the ice cream will see that there’s the following phases:
- Water ice crystals (you want these to be small and well spread out to prevent those crispy bits; these ice crystals are what make the ‘ice’ in ice cream)
- Sugar syrup (not all the water actually freezes, some might stay liquid and will have plenty of dissolved sugars inside, we discussed the important of sugars before when discussing the freezing point depression)
- Solid fat (the fat will have solidified at the low temperatures ice cream is stored)
- Air bubbles (oh so important to make a light, well melting and soft ice cream)
These three phases are all mixed together and separated (and stabilized) by proteins and in commercial ice creams other stabilizers to improve shelf life.
Top view of the 2-ingredient ice cream, even though you don’t see all those different phases, there are ice crystals, sugar syrup, solid fats and plenty air bubbles in there.
What happens when making ice cream?
This two-ingredient recipe really limits ice cream making to its two most important steps:
1. Aeration: we have to make sure those air bubbles are formed inside the chocolate. For that to happen we have to whip something that can actually hold on to those air bubbles. It needs to be able to hold on to the air bubbles long enough for the ice cream to freeze in the freezer. Once it’s frozen everything around the air bubbles will be so hard the air won’t be able to escape anymore. However, up to that point the air bubbles might still move and disappear.
2. Mixing: all the ingredients have to be mixed together homogeneously. We have to make sure the sugar dissolves well in the water, that the air bubbles are spread through evenly and that the fats are spread out evenly.
2-ingredient ice cream – Role of ingredients
In this 2-ingredient ice cream we use only two ingredients that again contain all the components we need! You will see that the ingredients both fulfill several roles at the same time to still make this complex ice cream structure.
The first is cream, more specifically cream suitable for whipping, it’s called different everywhere, but contains at least 30% fat. By whisking this cream you can create a foam and thus the air bubbles we need for making the ice cream. The reason cream can hold on to air bubbles pretty well is its high fat content. This fat, together with the proteins in the cream, will stabilize the air bubbles and prevent them from merging immediately.
The cream thus contributes the air bubbles, fat and part of the moisture and proteins.
Side note: Why you shouldn’t boil cream meant for whipping
If you decide to infuse some flavour in the cream (e.g. vanilla or coffee), make sure you do not actually boil the cream. Instead, only heat it up slightly (max. 40C). Cream that has boiled will have denaturated proteins. These aren’t good anymore in stabilizing the foam that is formed by the cream. Instead, you might not end up with a foam, but with butter! Any cream can be whipped too much resulting in butter instead of whipped cream. However, this boiled cream never got foamy but immediately switched over to the butter stage.
The other ingredient we’re using here is condensed milk. Condensed milk is boiled down, thickened milk with plenty sugar. In a sense it is a pre-mixed version of sugar + water + dairy. Since the sugar is already dissolved in the condensed milk there’s no need to heat up cream or milk to dissolve the sugar. Instead, all we have to do is gently pour it in the whipped cream (making sure to break as little bubbles as possible) and gently fold it through. Easy as that!
Wondering why we need sugar at all in ice cream? It’s to make a soft ice cream. Imagine freezing a cube of water. It will become rock hard. However, if instead we dissolve in sugar not all the water will actually freeze due to a phenomenon called the freezing point depression. This will make the ice cream softer. Combine this with some air and fat in the ice cream and it will result in a smooth silky ice cream!Aerat2. MxingThe otherThe
2-ingredient ice cream recipe
This 2-ingredient ice cream recipe makes a very smooth ice cream. However, I personally find it overly sweet (although opinions differed). You can reduce the condensed milk content, as stated in the recipe, that will affect the softness of the recipe as well (see explanation above in the condensed milk section), but might make it more agreeable to your taste.
- 250 ml cream (non sweetened, at least 30% fat)
- 200g condensed milk (this makes a pretty sweet ice cream, use 150g for a less sweet version
- Whip the cream until a firm foam has formed. Be sure not to overwhip to prevent butter from forming.
- Pour in the condensed milk, try to pour all in at one spot to prevent the foam from collapsing.
- Gently fold in the condensed milk, try not to break too many air bubbles.
- Pour the mixture in a container suitable for the freezer and leave in the freezer (-18C) for at least 10 hours (over night).
- The ice cream might be hard to scoop straight from the freezer, place in the microwave at 360W for 20s to soften.
Want to try somewhat more advanced ice cream recipes? Try out our semi freddo (pretty similar to this one, but slightly more refined flavours), our vanilla ice cream or our eggless ice cream (using custard!).
The post 2-Ingredient ice cream – On the power of whipped cream appeared first on Food Crumbles – The Food Science Blog.