bacteria cling This greatly increases the effective surface area of the wine, and regularly exposes all parts of the liquid to both oxygen and bacteria The result is a quick fermentation that takes only a few days Finally, there is the “submerged culture” method, in which free-swimming bacteria are supplied oxygen in the form of air that is bubbled through the tank This industrial method converts the liquid’s alcohol into acetic acid in 24–48 hours The intact acetic acid molecule, and the acid dissociated into its acetate and hydrogen ions Only the intact molecule is volatile and detectable in the nose by its distinctive smell Adding vinegar to an alkaline ingredient — egg whites or baking soda, for example — causes the acetic acid molecules to dissociate, and diminishes its aroma After Fermentation After fermentation, nearly all vinegars are pasteurized at 150– 160ºF/65–70ºC to kill remaining bacteria of all kinds, but especially the acetobacteria themselves, which respond to the disappearance of the alcohol by metabolizing acetic acid to water and carbon dioxide and thus weakening the vinegar Most vinegars are aged for a few months, a period in which their flavor becomes less harsh and more mellow, thanks in part to the combination of acetic and other acids with various compounds to form new, less pungent, often aromatic substances Common Kinds of Vinegar Cooks can choose among several different kinds of vinegar Though all have the basic aroma and pungency of acetic acid, each is ... kinds, but especially the acetobacteria themselves, which respond to the disappearance of the alcohol by metabolizing acetic acid to water and carbon dioxide and thus weakening the vinegar Most vinegars are... aged for a few months, a period in which their flavor becomes less harsh and more mellow, thanks in part to the combination of acetic and other acids with various compounds to form new, less pungent, often aromatic substances... new, less pungent, often aromatic substances Common Kinds of Vinegar Cooks can choose among several different kinds of vinegar Though all have the basic aroma and pungency of acetic acid, each is