Foams

A foam or froth (a froth is simply a foam with larger bubbles) is like an emulsion, except that it includes a gas, usually air, carbon dioxide, or nitrous oxide. Whether fluid or stiff, foams may function as sauces because they provide flavor and textural contrast. To stabilize the foam and prevent the bubbles from coalescing and collapsing, hydrocolloids are often added. Ideally, they should be surfactants that coat the gas bubbles and keep them from deflating.

While many of us associate culinary foams with the delicate and rarefied versions served as a part of modernist cuisine, foams have long been used in traditional cooking. Culinary uses of foams include cakes, breads, marshmallows, soufflés, and mousses.