mousse

French mousse means foam, froth, lather. It may come from Late Latin mulsa (a mixture of honey and water) or from a Frankish root related to 'moss' (German Moos, English moss — the plant that grows in soft, foamy-looking cushions). The culinary mousse — a light, airy preparation made by folding whipped cream or beaten egg whites into a flavored base — was named for its texture. It was foam you could eat.

Chocolate mousse appeared in French cuisine in the eighteenth century. The earliest published recipe may be in Menon's Les Soupers de la Cour (1755). The technique required beating eggs and chocolate together until light — a labor-intensive process before electric mixers. The mousse was aristocratic food: it required skill, time, and expensive ingredients. A poor person's dessert it was not.

Mousse entered English cookery terminology in the nineteenth century. By the twentieth century, mousse had expanded beyond desserts. Salmon mousse, chicken liver mousse, vegetable mousse — savory mousses became fixtures of mid-century entertaining. A mousse could be sweet or savory, hot or cold, set with gelatin or held together by egg whites alone. The word named a texture, not a flavor.

Hair mousse appeared in the 1980s — a foam styling product that used the same word because it was the same thing: a light, airy froth applied to a surface. Mousse au chocolat and mousse pour les cheveux — chocolate mousse and hair mousse — share a word because they share a physics. Both are air trapped in a matrix. The culinary technique and the cosmetic product are the same principle in different bottles.