How Does No-Churn Ice Cream Work?

The Science Behind Ice Cream

Before we can talk about how and why no-churn ice cream works, we first need to understand how regular ice cream works. The difference between a smooth, creamy homemade ice cream and a hard, icy one usually comes down to physics and chemistry.

To delve into why no-churn ice cream works, we first need to understand how sugars, fats, air, and stabilizers work together in regular ice cream. Milk and egg proteins also play an important role in regular ice cream, but since they aren’t components of no-churn ice cream, we’ll skip diving into that part for now.

The Role of Fat and Air in Ice Cream

A delicious, smooth, creamy ice cream texture comes from suspending and freezing tiny air bubbles within the mixture. In other words, ice cream is technically a kind of foam! Foams come up a lot in baking and cooking. Meringue is a foam, and so is whipped cream (more on that below).

While the proteins in egg whites trap air bubbles to create a foam in meringue, whipped cream and ice cream are made by suspending air bubbles within butterfat. Churning ice cream introduces those air bubbles while simultaneously preventing ice crystals from forming. Keeping large ice crystals from forming is the key to a smooth, creamy ice cream rather than an icy one.

Additionally, fat melts pretty much immediately when you bring it up to your body temperature. Therefore, the frozen ice cream melts almost instantly when you take a bite, creating a creamy texture as it melts.

How Different Types of Sugar Affect Ice Cream

Regular granulated sugars (brown and white) are composed of sucrose molecules. But other types of sugars exist on a molecular level, and in ice cream, the relevant ones are glucose, lactose, and fructose. Sugars play the second half of the equation in keeping ice cream scoopable.

Sugar water has a lower freezing point than plain water. The sugars dissolve into the milk, binding to the water molecules and helping keep the ice cream from freezing solid at a temperature where plain water would. But monosaccharides like glucose and fructose are much more efficient at binding water than a disaccharide like sucrose. (Sucrose is a di-saccaride because it is a fructose and glucose molecule holding hands; mono-saccharides like glucose and fructose are perfectly happy to go about life on their own). More monosaccharides in your ice cream means a softer, more scoopable ice cream.

The sugars also help break up the water molecules. Water molecules attached to sugar molecules can’t attach to other water molecules to form big ice crystals. The more we can interrupt those connections between water molecules, the better we can ensure there are no large ice crystals in the ice cream.

Using Stabilizers in Ice Cream

Most commercially available ice cream contains stabilizers such as xanthan gum, carob bean gum, and carrageenan. Stabilizers help keep ingredients together in the way you want them to be. In meringue, cream of tartar is often used as a stabilizer to keep the egg white proteins stronger and the air bubbles more effectively trapped. In whipped cream, gelatin can be used as a stabilizer to keep it from collapsing over time. In ice cream, gums are typically used instead.

With meringue and whipped cream, the goal is generally just to keep the air bubbles trapped within the protein matrix or fat globules. With ice cream, we also need to keep the water molecules away from each other. These gums help keep water molecules suspended in the ice cream as tiny droplets, rather than letting them find each other and form big ice crystals.

The Science Behind No-Churn Ice Cream

Now that we know the basic scientific principles behind creating a smooth, creamy ice cream, we need to figure out how to recreate that in a no-churn ice cream. With traditional ice cream, slowly churning the mixture as it freezes incorporates air bubbles and breaks up any ice crystals as they form. With no-churn ice cream, that mechanical agitation is not present. Therefore, we need to find ways to replicate the effects.

Reducing Water Content in No-Churn Ice Cream

One key factor in no-churn ice cream is using highly condensed and concentrated ingredients. If the biggest obstacle to a smooth, creamy ice cream texture is water molecules, then the simplest solution is also the most obvious one: use less water.

Sweetened condensed milk is usually used in place of regular milk in no-churn ice cream, and it pulls double duty. First, as the name suggests, the milk has been reduced down to a thicker consistency and most of the water has been boiled off. Second, as we’ll discuss further below, sweetened condensed milk is also an invert sugar product, which means it’s doing even more work behind the scenes.

For flavoring this no-churn ice cream, we’re using lemonade concentrate. Like sweetened condensed milk, this is a syrup with a high sugar content and very little free water. This is actually why syrups will generally yield better results than juices when flavoring no-churn ice cream.

Introducing Monosaccharides in No-Churn Ice Cream

As mentioned above, monosaccharides like glucose and fructose are more efficient in binding water molecules than disaccharides like sucrose. In commercial ice cream production, glucose syrup is often used as a sweetener. When making ice cream at home, you can use a homemade invert sugar syrup or light corn syrup. (Light corn syrup is a glucose syrup, and is different from high-fructose corn syrup. You can read more on the science behind corn syrup and how it’s useful in baking.)

Invert sugar syrups are created by heating sugar and water for a long period of time until the sucrose molecules break up into individual glucose and fructose molecules. Because sweetened condensed milk is also held at high heat for a long time, it is also an invert sugar product. Therefore, not only is using condensed milk a way to reduce the water content in no-churn ice cream, it’s also a way to introduce more monosaccharides into the mixture. Two birds, one very delicious stone.

Using Cream Cheese as a Stabilizer in Ice Cream

While commercial ice creams use commercial stabilizers and gums, cream cheese can be used as a stabilizer in homemade ice cream. Not all frozen lemonade pie recipes call for cream cheese. However, I made this pie with and without cream cheese, and the results were noticeably and significantly better with it. The final result of the no-churn ice cream has a more substantive mouthfeel, closer to real ice cream, and a much fluffier texture.

Adding cream cheese also helps stabilize the filling over time. My test batch made without cream cheese began weeping, developing ice crystals, and losing its shape after just a couple of days in my freezer. The version with cream cheese stayed fluffy and creamy for over five days.