Vinegar (Su)
Japanese: 酢（食酢）
A sour seasoning produced by acetic acid fermentation of alcohol via acetic acid bacteria. Varieties include grain, rice, and fruit vinegar.
Vinegar could be called a fermentation of fermentation. First, yeast converts raw materials into alcohol; then acetic acid bacteria transform that alcohol into acetic acid. The sourness born through this two-stage microbial relay carries umami and sweetness from the original ingredients. With natural antimicrobial properties, vinegar is essential for preserving food and indispensable at the Japanese table. Rice vinegar underpins sushi culture, while black vinegar is valued for its mellow umami and health properties. Fruit vinegar varieties are expanding, with persimmon vinegar and apple vinegar made from local fruits in various regions.