Pure acetic acid (CH₃COOH) is a clear, colorless liquid that is found in vinegar. In fact, the name for the acid is derived from the Latin word for vinegar, acetum. When highly concentrated acetic acid is corrosive and can cause severe burns; in dilute form it is useful in food preservation and a variety of other applications. Acetic acid is an organic acid because, like all organic compounds, it contains carbon. Like most acids, acetic acid tastes sour or tangy and has a pungent, biting odor. It is this quality that gives the vinegar used in salad dressings its characteristic tart flavor. Acetic acid constitutes about 5 percent of most table vinegars.

It is thought to have been first produced accidentally as a by product of wine production, because when fruit juices are fermented for too long they are converted to acetic acid. In commercial practice...