Definition: Mousse

A foamy liquid caused by carbon dioxide on the surface of a vat during fermentation. Be careful of the suffocating carbon dioxide gas. A lit candle proves the presence of oxygen.

Fine foam that precedes the string of bubbles when filling a flute of sparkling wine.

Foam head forming on beer. A two-centimetre foam head is beneficial for insulating the beer from contact with air, which quickly alters its taste.