Final answer:
To make sweet cream cold foam, froth the cream with a sweetener; for salted cream cold foam, add salt or salted butter before frothing. For homemade ice cream, dissolving salt in water mixed with ice can lower the temperature to optimal levels for freezing the mixture as the salt lowers the freezing point of water.
Step-by-step explanation:
To answer how to make sweet cream cold foam and salted cream cold foam:
The correct method is B. Froth cream with sweetener for sweet cream; Add salted butter to cream for salted cream. The process of frothing helps to create that rich and airy texture that is characteristic of cold foam. For a simple sweet cream cold foam, cream is typically frothed with a sweetening agent such as vanilla syrup or simple syrup. For a salted cream cold foam, a pinch of salt or even salted butter is incorporated into the cream before frothing, to achieve that distinctive salty-sweet taste.
Now, when we dive into the chemistry behind making homemade ice cream, we find that temperature control is critical. As mentioned, temperatures down to -3°C are essential for achieving the desired consistency. The process of dissolving NaCl (salt) into water to mix with ice cubes creates a saltwater solution that has a lower freezing point than pure water. This helps to freeze the liquid inside the ice cream maker to the optimal temperature for making homemade ice cream. In the technique described, adding one part salt to 11 parts water (by mass) will lower the freezing point significantly, although the precise new freezing point would require additional calculation based on the colligative properties of the solution.