Milk science

Milk is three ingredients wearing one coat. Proteins build the foam — steam unfolds them and they wrap themselves around air bubbles like scaffolding. Fat carries flavor and gives texture, thinning the foam slightly while making it silky. Lactose is the sweetness — and its perceived sweetness climbs as milk warms, peaking between roughly 55 and 65 °C.

Push past about 68–70 °C and the deal collapses: whey proteins overcook, sulfurous notes appear, the sweetness flattens, and the foam turns stiff and dry. Scalded milk isn’t a taste crime because of tradition; it’s chemistry.