Why does ice cream melt?
asks Kim Price, via email. Whether premium, low-fat, nonfat, or low-carb, all ice cream melts on a hot summer day, dripping down the cone and onto the front of your shirt. In melting, ice cream is just behaving like any other bit of frozen, icy matter, suddenly exposed to warm air. Matter changes its state, depending on temperature and pressure. Liquid water boils into a gas (water vapor), freezes into a solid (ice), and melts back into a liquid if left out of the fridge. But ice cream isn’t plain water, and how (and how fast) it melts depends on more than just temperature. The melting qualities of ice cream are actually a favorite focus of some food scientists, since how ice cream melts affects how it tastes. If you’ve ever made ice cream at home—or idly read the carton label as you dug in with a spoon—you know ice cream’s basic ingredients: cream and/or milk, sugar, and flavoring, plus egg yolks in the custardy varieties. Some brands add chemical stabilizers and emulsifiers. Finally,
