Alcohol vs vinegar
Exploring the differences between alcohol and vinegar: Alcohol is a clear, colorless liquid that is made through the fermentation of sugar or starches while Vinegar, is made through the fermentation of ethanol, typically from wine or cider.
Alcohol and vinegar sit at two ends of the same fermentation pathway, and confusing them has real consequences for process design in a beverage or condiment plant. Chemically, an alcohol is any organic compound with a carbon atom bound to the hydroxyl functional group (-OH). The term "alcohol" originally referred to ethanol, also known as ethyl alcohol — the primary alcohol used as a drug and the main alcohol found in alcoholic beverages.
Vinegar is defined by a different functional group, the carboxyl group (-COOH). Its active constituent is acetic acid (CH3COOH), which makes up about 5-20% of vinegar; the balance is water together with other trace chemicals such as flavourings. Acetic acid is produced when ethanol is fermented by acetic acid bacteria. In essence, vinegar is simply alcohol — more specifically ethanol — that has been exposed to oxygen and bacterial fermentation. The complete route is alcoholic fermentation plus acetic fermentation equals vinegar.
The practical distinctions follow from that route. Alcoholic beverages are made directly from fruits after fermentation and are meant for immediate drinking, with ethanol as the main component. Vinegar is made by further fermentation of alcohol such as wine or beer, has acetic acid as its main component, and is used mainly as a cooking ingredient or in pickling. Confusion also arises because vinegar can be found in other alcoholic beverages such as wine, beer and fermented fruit juices, and natural vinegars may still contain 0.5-2% alcohol.