Product obtained from the fermentation of wine. During this process, the ethyl alcohol present in the wine is transformed into acetic acid, thanks to the action carried out by some microorganisms. The alcohol content of the vinegar must not exceed 1.5%. Produced by large industry, vinegar can also be prepared at home, by adding a small amount of vinegar or "mother" (ie a microcolony of bacteria) to the wine which is taken from the bottom of a bottle of vinegar. The bottle should be left open for a month in a warm area so that it can ferment.