A kind of fungus that floats in wine. In Italy, all dregs of wine, left-overs and undrunk wine that has gone sour is poured into a container, often a barrel, with this fungus in it and good vinegar will be the end result. Kept in many Italian homes, officially the mix should be two parts vinegar to one part wine in a barrel. The barrel is not sealed and the lid is left off so that mixture is exposed to the air. Vinegar is taken off from the bottom and the barrel is topped up with remnants of wines and vinegars used in the household.
