Acetic Acid

All wine contains trace acetic acid (0.2-0.6 g/L is normal). Acetobacter bacteria produce it when wine is exposed to oxygen. Above 0.7-0.8 g/L, the sharp vinegar character becomes objectionable. Some elevated VA is tolerated in certain styles (Amarone, Sauternes) where it lifts aromatics. The legal limit varies by country and wine type.