Foams

Light colloidal dispersions of a gas such as air through a liquid or solid, usually created by whipping or frothing. Foams are inherently unstable, so stabilisers must form the gas-bubble membranes. Egg white’s strong foaming capacity suits aerated foods such as meringues and soufflés; foams also arise in winemaking and soft-drink production. Culinary foams — from classic chantilly to modernist espumas dispensed from siphons — rely on the same physics as industrial aeration: bubble size distribution sets texture, with finer bubbles giving creamier mouthfeel. Stability is engineered with hydrocolloids and measured instrumentally, since a foam that collapses before serving fails its purpose.