Iio Jozo has been making vinegar in Miyazu, on the northern Kyoto coast, since 1893. The brewery starts where industrial producers do not: it brews its own sake first, then acetifies it, using 320g of pesticide-free rice per litre — roughly eight times the quantity used in standard commercial rice vinegar. The fermentation is static, not submerged: the acetobacter cultures work at the surface over several months rather than being forced through an industrial acetator in days. The vinegar is then aged in cedar barrels for over a year before bottling. The result is a product with a fundamentally different character — mellower, rounder, and substantially more complex than the clear, sharp acidity of commodity rice vinegar. The 1.8L format is for kitchens that use it seriously.

Junmai Fujisu (純米富士酢) translates as "pure rice Fuji vinegar": 純米 (junmai) means pure rice — no added alcohol or acids — and 富士 (Fuji) references the brewery's flagship designation, a name synonymous with quality in Japanese artisan vinegar. Miyazu, on the Sea of Japan coast in northern Kyoto Prefecture, has clean groundwater and a temperate climate suited to slow fermentation. The brewery's process — jijō-su (自醸酢), meaning self-brewed vinegar — has been continuous since the Meiji era. The su-gura (酢蔵), or vinegar warehouse, uses the same biological sequence that Iio Jozo has followed for over a century: cook the rice, saccharify with koji, ferment to sake, seed with acetobacter, acetify slowly at the surface, and age. The industrial alternative compresses this to days. The 1.8L Fujisu takes the better part of two years from rice to bottle.

What is the difference between Iio Jozo and standard rice vinegar?

Volume, time, and method. Standard commercial rice vinegar uses around 40g of rice per litre, submerged fermentation in industrial acetators (days rather than months), and no barrel aging. Iio Jozo uses 320g of rice per litre, static surface fermentation over several months, and over a year in cedar. The flavour difference is significant: commercial rice vinegar is sharp and one-dimensional; Fujisu is mellow, slightly sweet, and umami-present. It seasons differently — it integrates rather than cuts.