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 [1] (typically 5%) and higher concentrations for pickling (up to 18%). Natural vinegars also contain small amounts of tartaric acid, citric acid, and other acids. ( Wikipedia ).