— COLUMN / Brewery
Masumi — The Suwa Brewery That Gave Japan Its Most Important Yeast
Miyasaka Jozo in Suwa, Nagano, is where Kyokai Yeast No.7 was discovered — and where exceptional sake has been made ever since.
2026年3月5日
Miyasaka Jozo, producer of the Masumi brand, occupies a specific place in sake history: it is the brewery from which Kyokai Yeast No.7 was isolated in 1946. That yeast — clean, reliable, mildly fruity — became the most widely used sake yeast in Japan, shaping the flavor profile of countless sakes brewed by hundreds of breweries. Masumi gave Japan its brewing foundation.
Suwa and Its Water
Suwa sits in a highland basin at over 700 meters elevation in central Nagano, surrounding one of Japan’s oldest lakes, Suwa-ko. The water that descends from the surrounding mountains and accumulates in the Suwa basin has a distinctive mineral profile — neither the extreme softness of Niigata nor the hardness of Nada, but a balanced medium that allows both fragrance and body to develop.
The Range
Masumi’s range is notable for its breadth and consistent quality across price points. The entry “Nanago” (Seven) celebrates the No.7 yeast heritage. The flagship “Okuden Kantsukuri” junmai is one of the most dependable food sakes in Japan — reliable, full-flavored, adaptable. At the premium end, “Miyasaka” junmai daiginjo expressions show what the Suwa water and terroir can produce when taken to their elegant extreme.
International Presence
Masumi has invested significantly in international markets and has established one of the stronger reputations among Japanese sake breweries for consistent international distribution and quality maintenance through the export chain. Finding Masumi outside Japan is among the easier tasks in sake importing.
The Long View
What strikes any long engagement with Masumi is its patience. The brewery has been operating for over 350 years. It does not pursue trends; it waits for the sake industry to catch up with what it has always known about quality. In the case of Yeast No.7 — perhaps the most important single brewing discovery in modern Japanese sake history — the brewery literally gave its discovery to the entire industry. That is a kind of generosity that deserves acknowledgment.