Homemade no-machine ice cream is a delicious treat that can be made without the need for an ice cream maker. The science behind this process lies in the principles of freezing point depression and emulsification.

Freezing point depression refers to the phenomenon where the freezing point of a liquid decreases when a solute is added. In the case of ice cream, the solute is usually salt. When salt is added to ice, it lowers the freezing point of the ice, allowing it to get colder than 0 degrees Celsius without melting. This super cold environment is essential for freezing the ice cream mixture.

Emulsification is another key aspect of homemade ice cream. Emulsifiers are substances that help mix two immiscible liquids, such as oil and water. In ice cream, emulsifiers like egg yolks or stabilizers like cornstarch help create a smooth and creamy texture by preventing the formation of ice crystals.

So, how does it all come together? Let's look at an example recipe for no-machine vanilla ice cream:

1. Start by combining heavy cream, sweetened condensed milk, and vanilla extract in a mixing bowl.
2. In a separate bowl, whisk together egg yolks and sugar until well combined. This step adds richness and helps with emulsification.
3. Gradually add the egg yolk mixture to the cream mixture, whisking continuously.
4. Pour the combined mixture into a shallow dish or container.
5. Place the dish in the freezer and let it freeze for about 2-4 hours, or until it reaches a semi-solid consistency.
6. Every 30 minutes during the freezing process, remove the dish from the freezer and vigorously stir or whisk the mixture. This breaks up any ice crystals that may have formed and promotes a smoother texture.
7. Once the ice cream is firm but still scoopable, it is ready to be served and enjoyed!

References:

• Science of Ice Cream: https://www.exploratorium.edu/cooking/icecream/science-of-ice-cream.html
• What's Cooking America: https://whatscookingamerica.net/icecream/icecreamtips.htm

By understanding the science behind freezing point depression and emulsification, you can create your own delicious homemade no-machine ice cream with various flavors and mix-ins. Enjoy experimenting and indulging in this frozen treat!