The first time I went to Nagano, there had just been a massive snowstorm that seemed to put this mountainous area of Japan at a standstill. The sun reflected brightly off of the snow piled high on the roads all around us and into our eyes as our bus pushed on to our final destination. I knew about the basics of sake; I knew that rice was soaked and steamed, I knew that water was essential, so I imagined this high altitude mountain run-off, mineral rich spring water would have a unique effect on the sake at the brewery I was about to visit. I didn’t know that one brewery would have such pride in their yeast and that their yeast would change the way I think of yeast in sake production.
By definition, yeast turns glucose into alcohol and for almost 110 years, the national brewing institute of Japan has focused their efforts on isolating the yeasts most beneficial in sake production. In sake, yeast not only does the dirty work of converting alcohol into carbon dioxide but has a strong contribution on the aromatic complexity and intensity of a sake. All types of yeasts are used, from natural yeast falling from the rafters of the brewery to carefully cultivated yeasts in laboratories and yeast delicately sampled from flowers to yield aromatics ranging from wildly floral and vibrant to dark and mushroomy.
During my visit to that sake brewery in Nagano, Cella Masumi, there was a small dimly lit plaque in on a wall somewhere between rows of tanks that are used for sake production. The plaque was all in Japanese of course but it goes to tell a story about Yeast #7. This special yeast was discovered in 1946 at that very spot where the plaque still stands. The sake coming out of the fermentation tanks in that corner of the brewery where that plaque now stands proved year after year to be particularly and uniquely aromatic. The yeast was brought to the Central Brewers Union for isolation and, with its subtle candied fragrance, is one of the most popular yeasts in production today and sold to sake breweries all over Japan.
In modern sake production, the production isn’t as romantic as yeast cells dancing off of the rafters above on the ceiling of a sake brewery into an open fermentation vat to begin fermentation. These days, a beery looking liquid is collected into test tubes with different codified names and numbers. The yeast is a solution that is added from a beaker of some sort into the starter mash to begin the process of fermentation, but it all started from an accident, and in the case of Masumi and their Yeast #7, it was a happy accident indeed that made their sake famous.
Elliot Faber is the sommelier and beverage manager of two cool Japanese restaurants in Hong Kong: Yardbird and Ronin. He is also one of the world’s experts on sake, Japanese whisky, shochu, awamori and Japanese beer.
