Junmai Kaya Brown (300 ml)

In 1946, Masumi's brewers isolated a yeast strain from their fermentation tanks in Suwa, Nagano — a discovery so consequential it became Kyokai Yeast No. 7, now deployed by over 60% of sake breweries across Japan. Every bottle of Masumi is still built on that same house culture.

The Suwa Moto-machi kura sits where the ancient Koshu Kaido road meets the Kirigamine Highlands route, in a district historically called Shimizu-machi — 'Clear Water Village' — drawing snowmelt from the Yatsugatake (Eight Peaks) Range. Suwa Basin's cold alpine climate slows fermentation and preserves aromatic precision in the moromi.

The Kaya Brown is brewed using Masumi's house-wide yamahai yeast-starter method: natural lactic-acid bacteria are cultivated in the shubo over approximately two weeks before yeast fermentation begins — no commercially added lactic acid — yielding higher natural acidity and deeper umami structure than the sokujo norm.

Primary rice is Miyama Nishiki, a Nagano-grown variety bred for cold-climate brewing. What sets this brewery apart is the refusal to reserve yamahai for premium tiers: it runs through the entire range, making Masumi one of very few large-volume kura to absorb that labour cost across its range.

The 300 ml format delivers the full Suwa terroir expression — lactic depth, clean alpine water character, and food-driven structure — in a format suited to single-service precision.