Classic Mixology: Cocktail & Mixed Drink Recipes

vinegar

What it is:  Additive

Acidic liquid processed from the fermentation of ethanol (in wine, beer, cider, etc.) in a process that yields its key ingredient, acetic acid. Natural vinegars also contain small amounts of tartaric acid, citric acid, and other acids. The word "vinegar" derives from the Old French vin aigre, meaning "sour wine".

Further reading:  http://en.wikipedia.org/wiki/Vinegar