Japanese Vinegar Spectrum — Su, Kurozu, and Specialty Vinegars (酢のスペクトル)

Japan — kome-su (rice vinegar) has been produced in Japan since the Nara period (8th century). The Kyoto vinegar-making tradition (Iio Jozo, est. 1893) uses traditional wooden barrel fermentation. Kurozu's production tradition in Fukuyama (Kagoshima) dates to the late Edo period, when local rice farmers developed the earthenware-jar brewing method that is still used today.

Japanese vinegar (su, 酢) spans a wider range of flavour, acidity, and colour than any single other cuisine's vinegar tradition — from the mild, clean kome-su (米酢, rice vinegar, 4–5% acidity, pale golden) to the deep, mellow kurozu (黒酢, black vinegar, aged for 3+ years in earthenware pots until developing an amber-black colour and a complex, almost balsamic character). The primary types: kome-su (rice vinegar) — the standard sushi rice seasoning and general-purpose Japanese vinegar; kurozu (black vinegar, from Kagoshima) — aged, complex, used as a condiment and health food; sanbaizu (三杯酢, three-cup vinegar) — rice vinegar + soy + mirin as a composite dressing; awasezu (合わせ酢, sushi vinegar) — rice vinegar + salt + sugar for sushi rice.

Kome-su's flavour is gentle and clean — a mild acidity with a faint sweetness and a clean, neutral character that adds brightness without asserting a strong wine or grain flavour. This is precisely why it works in sushi rice: the vinegar elevates the rice's flavour without competing with the fish. Kurozu's aged character is completely different — deep, complex, slightly caramelised, with hints of umami from the long fermentation; a few drops on stir-fried bitter greens or cold tofu transforms the preparation with a quiet, complex acidity that bears no resemblance to ordinary vinegar.