Cold foam is a frothy milk topping to add a velvety texture when drinking a cold brew, iced coffee, and even iced teas. The Starbucks version is lightly sweetened with syrup and flavored, depending on the drink. It's heavier than steamed milk foam because it uses heavy cream that's at least 36% milk fat. It can be whipped by hand in a bowl, in a blender, hand-held milk frother, or shaken in a jar. It should be light and pourable, not thick like whipped cream.