During the souring process, the alcohol in the wine would be converted into acetic acid by the action of Acetobacter. Acetic acid, CH3COOh, is a colorless, volatile liquid at ambient temperature. The pure compound, glacial acetic acid, owes its name to its ice-like crystalline appearance at 15.6 °C.
The acetic acid of the vinegar is the preservative agent. Vinegar is formed by acetic acid fermentation of alcoholic liquids. The acetic acid formed will preserve the liquid, provided air is excluded after vinegar fermentation is over.
Bacteria normally found in the environment, the classic culture source, often fostered fermentation that yielded undesirable flavors and characteristics.
As is the case in almost all modern fermentation, vinegar fermentations today use specific bacterial cultures that have been isolated and proved to be most effective for this purpose.
Vinegars are extensively employed in preparing salad dressings and mayonnaise, sour and sweet pickles, and numerous sauces and catsups.
Acetic acid in vinegar