Coffee milk foam

The principle of milk foam is very simple, but it is the product of a close combination of milk and air. The way to make milk foam is to pump air into the foam. The practice of milk foam is divided into hot and cold. Hot milk foam uses the steam nozzle of a coffee machine to pump steam into the milk. On the one hand, it heats up, and on the other hand, it produces milk foam. Cold milk foam is made by hand with a milk bubble machine.