food vinegar is made from **** or apple cider, or barley or rice malt - aerobic bacteria are fed on alcoholic fermentation (as opposed to alcoholic fermentation, oxygen is "present" during acetic fermentation) those bacteria (Acetobacterium) biologically oxidize alcohol to acid acetic acid (after all, I think people do the same) industrial acetic acid (and Polish food vinegar) are made in a much rougher way from potato alcohol, which saturates oak sawdust inoculated with these bacteria