Vinegar is sometimes infused with spices or herbs—as here, with oregano.Vinegar is 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.