Dry Ice Ice Cream!
Mad Science
Chemistry/Physics
Materials:
§ 2 cups of half and half
§ 2 cups of heavy cream
§ 3/4 cup of sugar
§ 2 eggs
§ 1 teaspoon of vanilla
§ Pinch of salt
§ Food Grade (restaurant) 10 lb CO2 fire extinguisher or block of dry ice
Procedure:
1. Mix the half & half, heavy cream, sugar, eggs, vanilla and salt in a large metal bowl, stir completely!
2. If you are using the food-grade CO2 fire extinguisher, discharge it into a clean pillow case for about 10 seconds. You will end up with several pounds of finely powered dry ice.
3. If you are using block dry ice, place it into a heavy Ziploc bag and crush with a hammer or other heavy object. CAUTION: You must crush the ice into very fine pieces, almost powder; you don’t want big pieces of dry ice in your ice cream!
4. Put several large spoonfuls of powdered dry ice directly into the ice cream mixture, add more dry ice as needed to get the ice cream to the desired texture. Stir until frozen.
5. Serve plain or with your favorite topping!
The SCIENCE!
As liquid evaporates it gets cold, because it takes energy to turn a liquid into a gas and that energy comes from heat drawn out of the liquid. Evaporating pressurized liquid carbon dioxide draws so much energy out of it that about a 1/3 ends up frozen solid, as dry ice. Using the cold CO2 is a great way to freeze your ice cream! The result is...interesting! Carbon dioxide is what makes soda fizz, so the ice cream comes out carbonated. Not bad, but don’t expect to see CO2 crunch in the ice cream freezer at your local store (from Popular Science How 2.0).