Derived from the French vin aigre, "sour wine," vinegar is made by bacterial activity thats converts fermented liquids such as wine, beer or cider into a weak solution of ACETIC ACID (the constituent that makes it sour). Vinegar has been used for centuries for everything from beverages, to an odor-diminisher for strong foods such as cabbage and onions, to a hair rinse and softener. There are a multitude of vinegar varieties available today. a liquid produced from the fermentation of ethanol in a process that yields its key ingredient, acetic acid. The acetic acid concentration ranges typically from 4 to 8 percent by volume for table vinegar (typically 5%) and higher concentrations for pickling (up to 18%) although in some countries the minimum strength may be less. Natural vinegars also contain smaller amounts of tartaric acid, citric acid, and other acids. It has been used since ancient times, and is an important element in Western and European, Asian, and other traditional cuisines of the world. The word "vinegar" derives from the Old French vin aigre, meaning "sour wine." Louis Pasteur showed in 1864 that vinegar results from a natural fermentation process.