Liquid Nitrogen Ice Cream

Q: What makes liquid nitrogen ice cream so special?

Liquid nitrogen is very cold. At normal atmospheric pressure, liquid nitrogen will boil at temperatures above -195.8 degrees Celsius (-320.4 degrees Fahrenheit). Liquid nitrogen is used for preserving biological samples, freezing food, cooling equipment, and other applications.

You can also use it to make delicious ice cream.

Ice cream is an emulsion, or a combination of liquids that normally wouldn’t mix together. In ice cream, liquid particles of fat are distributed in a mixture of water, sugar, and ice. Fat is nonpolar, meaning that charges are evenly dispersed in the molecule. Water, on the other hand, is polar, and has separate regions of positive and negative charges. Polar molecules tend to “like” mixing with other polar molecules, and nonpolar molecules prefer other nonpolar molecules. Mixing polar and nonpolar molecules together is a bit more difficult, as they tend to separate. To make ice cream, an emulsifier, such as egg yolks, can be used to prevent the fat from separating away from the water. Another important ingredient for ice cream is air. As the ice cream b*ase is mixed, air pockets are introduced, creating a foam. The end result is (hopefully) a cold foam with small, evenly distributed ice crystals making a creamy texture.

The benefit behind using liquid nitrogen to freeze ice cream is its speed. Slowly freezing the ice cream can allow the ice to melt before refreezing, causing the ice crystals to grow bigger and become less uniform. Larger ice crystals create a grainier mix. If you can freeze the ice cream faster and prevent the thaw and refreezing, you can make smaller ice crystals, making a smoother, creamier substance. Because liquid nitrogen freezes the ice cream quickly, tiny ice crystals form. (Of course, too much liquid nitrogen and cooling can cause the ice cream to freeze too quickly, and you’ll just be left with a solid chunk.)

So how exactly does someone make liquid nitrogen ice cream? There are a ton of recipes out there. In general, they consist of sugar and dairy products such as heavy whipping cream, half and half, milk, or condensed milk. Sometimes vanilla is used as a flavor enhancer and eggs or egg substitutes are used for consistency, as the egg yolks contain emulsifiers that help to blend the ingredients. Furthermore, the fat and protein in the egg yolks also help to prevent water from forming large ice crystals.

My standard liquid nitrogen ice cream recipe uses the following:
• 1 quart heavy whipping cream
• 1 quart half and half
• 1 cup sugar





• ¼ cup egg beaters
• 1 tablespoon vanilla extract

To make the ice cream, mix the above ingredients in a large bowl. Once that’s done, pour in some liquid nitrogen- maybe about a quart. Stir the mixture, then add some more liquid nitrogen and stir again. Keep adding liquid nitrogen and stirring until you reach the desired creaminess.

I’ve also added syrups and flavors to batches to make something a little different than plain vanilla. Liquid syrups mix very well with the ice cream. My personal favorite is caramel syrup, though chocolate and strawberry have gone over well, too. (Heck, you can even mix syrups- chocolate caramel ice cream, anyone?)

A few notes on safety: you really should wear gloves and goggles to protect your hands and eyes from liquid nitrogen. When using liquid nitrogen to make ice cream, I prefer using a large stainless steel bowl, since it won’t crack from the cold liquid nitrogen. I also prefer mixing with a large wooden spoon because it won’t crack or conduct the cold.

If you’re worried about lactose intolerance, allergens, or dietary restrictions, there’s a really simple alternative recipe: replace the dairy products with coconut milk. The egg beaters can be left out if you’re avoiding egg products, though the consistency may be a bit off due to the lack of emulsifiers. You just need 2 quarts of coconut milk to 1 cup of sugar. (You may even be able to cut the sugar if you don’t want something that sweet.) The result is an icy tropical treat.

I’ve never tried liquid nitrogen with soy milk or almond milk, so if you try it, let me know how it works out.