Introduction: "Dry Ice" Ice Cream!

About: I am a college student from California, and I love robotics, science, programming, and engineering. I love instructables because I love to build things.

WARNING: As you may have guessed, this instructable involves the use of dry ice. Dry ice can be very dangerous, so be safe with it.

Now, if you have made homemade ice cream, you have likely had a few problems with it. The first being that it takes a while to freeze. I am not a very patient person, so when I first made ice cream, it was the longest half hour of my life. I tried to solve this problem with a ice cream maker that was a sphere so that you would roll it around for a while and all of a sudden you would have ice cream (it was made of a hard plastic so you couldn't play soccer or any other normal ball sport).

The second major problem with homemade ice cream is the texture. Homemade ice cream tends to have an icier or crunchier texture compared to store-bought varieties. This has everything to do with the freezing conditions of the ice cream. The slower the ice cream is frozen, the larger the ice crystals will be. The key to a super creamy texture is to freeze it as fast as possible. This leads to people making liquid nitrogen ice cream, but liquid nitrogen is fairly hard to obtain in small quantities. Dry ice, however, you can usually get at your local grocery store. What follows are my escapades with dry ice cream.

The following recipe is adapted from http://thepioneerwoman.com/cooking/2009/07/vanilla..

Step 1: Ingredients

The following quantities are for about a half gallon of vanilla ice cream:

- 3 cups of half and half

- 3 cups of heavy whipping cream

- 2 cups of sugar

- 7 eggs

- 1 tsp of vanilla extract

- 1/4 of the weight of the ice cream of dry ice (for example: if there is four pounds of ice cream, one pound of dry ice is necessary). This will end up being somewhere around 1 pound of dry ice.

Step 2: Cooking Up the Ice Cream

In a pan or pot, mix the half and half with the sugar. Heat this mixture over low heat.

At this time take the egg yolks and whisk them until they are light and fluffy.

Once the half and half mixture is "simmering" (some small bubbles are appearing on the surface), slowly pour about a half cup of the half and half mixture into the eggs to "temper" them (make sure they don't cook when they hit the heat). After you mix the eggs, pour them and the vanilla into the half and half mixture, stirring all the while. Continue stirring and move on to the next step.

Add 3 cups of heavy whipping cream to a large mixing bowl so that it can come closer to room temperature (this bowl will need to be big enough to accommodate all of the ice cream as it will be the final mixing bowl).

Once the cream and egg mixture has become a thicker, custard-like mixture, pour it into the cream in the large mixing bowl. Mix this completely, then cool it to room temperature in a refrigerator.

Step 3: Putting the Dry Ice in Dry Ice Cream

Break up the dry ice with a clean hammer or meat tenderizer. You should try to break it so that no piece is bigger than one cubic inch, but do not grind all of it into a powder, because you will lose most of it to sublimation.

Once the dry ice is broken and the ice cream is at room temperature, put both in a large mixing bowl and mix slowly making sure to move the dry ice around and not let it stick to the side of the bowl. In about 5-10 minutes you will have ice cream!

Unless you plan on eating this immediately, I would suggest throwing this ice cream in the freezer, because a lot will be melting. In an hour or two you will have perfect ice cream.

If you do go ahead and eat this immediately, be careful since there still may be chunks of dry ice left.

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