vinegar, sour liquid condiment that depends etymologically, and often materially, on wine. The French word for it, composed of vin (wine) and aigre (sour), is a direct descendant of its Latin equivalent. Not just wine but any solution containing a low concentration (less than 15%) of ethanol will turn to vinegar if exposed to oxygen. The ethanol is oxidized first into an aldehyde and then to acetic acid by the oxygen in the atmosphere. Winemakers over the centuries have learned to shelter wine from the action of atmospheric oxygen, and nowadays will do all they can to prevent their wines turning to vinegar, and ‘vinegary’ is a tasting term of great disapprobation (while ‘winey’ is quite a compliment when applied to a vinegar). Once the volatile acids in a wine have reached a certain point, however, it can have a potable future only as wine vinegar.
