新政酒造Aramasa Shuzo

In 1930, a yeast was found fermenting wild in a brewery in Akita City. It was catalogued as Kyokai No. 6, and it is the oldest association yeast still in commercial use anywhere in Japan. The brewery where it turned up was Aramasa Shuzo, founded in 1852. For most of the century that followed, the rest of the industry moved on to newer strains that threw off louder, fruitier aromas, and Aramasa's own claim to the yeast sat largely dormant.

Yusuke Sato changed that. He had studied English literature at Tokyo University and worked as a journalist before he came home in 2007 to take over the family business as its eighth-generation head. He found a brewery that had been losing money for twelve straight years, making ordinary sake the ordinary way: commercial yeast, sokujō lactic acid, brewing alcohol added at the end to stretch the volume. Safe, shared by most of the industry, and worth seeking out by almost no one.

His first decision was to stop. No more added alcohol. No more commercially synthesized lactic acid. The brewery would switch to junmai: rice and water, nothing else. Sales dropped further at first. The brewer who had run the kura for years left, and between 2008 and 2011 the brewing team dissolved almost entirely.

Then he built something stranger than a return to tradition. Aramasa committed to that single inherited yeast, No. 6, for every product it made, and scaled production down from roughly 6,000 koku to 2,000 to bet on it. By 2015 the brewery had gone fully to kimoto, the most labor-intensive starter method, in which lactic acid develops naturally in the mash over weeks instead of being added in hours. No. 6 yeast, kimoto starter, Akita-only rice, wooden fermentation vats: every choice pulled Aramasa toward the slow end of the spectrum, away from industrial sake. What came out was low in aroma, firmly built, deeply fermented, nothing like what the market had been trained to expect from premium sake.

Sato has said he is trying to make sake the way it would have been made if no shortcut had ever existed. Production stays deliberately small. The waiting lists are long.

Key facts

• Founded 1852 in Akita City by Uhee Sato; Kyokai No. 6 yeast discovered at the kura by a family ancestor in 1930, now the oldest association yeast still in use in Japan
• Eighth-generation owner Yusuke Sato joined in 2007, when the brewery had been operating at a deficit for twelve consecutive years
• Eliminated added brewing alcohol and commercially synthesized lactic acid (sokujō method); converted entirely to junmai (rice and water only)
• Exclusive use of Kyokai No. 6 yeast across all products, combined with traditional kimoto fermentation (fully adopted by 2015)
• Uses only Akita Prefecture-grown rice; ferments in wooden vats (kioke); began pesticide-free cultivation in own fields from 2018
• Production deliberately reduced from approximately 6,000 koku to around 2,000 koku; premium positioning replaced volume
• The No. 6 series and Colors limited releases are distributed through a restricted network; secondary market demand is significant