The word vinegar is a derivation of the French term vin aigre, which means "sour wine." It is produced by adding bacteria to alcohol, changing it to acetic acid in a controlled fermentation process. The alcohol can be made from grapes (red or white wine vinegar), grain (distilled white vinegar), apples (cider vinegar) or rice (rice wine vinegar). Balsamic vinegar is made from sweet white grapes and aged in barrels for years to develop the typical brown color and mellow sweet-and-sour flavor. Wine vinegars and balsamic vinegars contain sulfites to control unwanted bacterial activity. There has been an explosion of interest in vinegars and many types are available in supermarkets and specialty markets. Vinegar is an ingredient in salad dressings, marinades and sweet-and-sour sauces. Vinegar may also be used as a condiment and for preserving and pickling.