Re: fermentation, a specific question

The production of alcohol is generally done using yeast as the fermenting agent. Yeast metabolizes the sugars with alcohol resulting as the break down product.

Vinegar (French: vin = wine, aigre = sour) is a fermentation of the alcohol, usually by acetobacter species. These organisms convert the alcohol to acetic acid (vinegar) and water.

Acetobacter are aerobic organisms. Hence, sealed bottles of wine don't turn to vinegar whereas wine that has been opened (and aerated) can be fermented into vinegar.