Vinegar is an acidic liquid processed from the fermentation of ethanol in a process that yields its key ingredient, acetic acid (also called ethanoic acid). It also may come in a diluted form. The acetic acid concentration typically ranges from 4 to 8 percent by volume for table vinegar (typically 5%) and higher concentrations for pickling (up to 18%). Natural vinegars also contain small amounts of tartaric acid, citric acid, and other acids. Vinegar has been used since ancient times and is an important element in European, Asian, and other cuisines. The word "vinegar" derives from the Old French vin aigre, meaning "sour wine". Wine vinegar is made from red or white wine and is the most commonly used vinegar in Mediterranean countries and Central Europe. As with wine, there is a considerable range in quality. Better quality wine vinegars are matured in wood for up to two years and exhibit a complex, mellow flavor. Wine vinegar tends to have a lower acidity than that of white or cider vinegars. There are more expensive wine vinegars that are made from individual varieties of wine, such as Champagne, Sherry, or pinot grigio.