Akita Sake: A Yeast from 1930 That Is Still Alive

Nearly all the yeast used in sake today descends from the “Kyokai yeasts” distributed by the Brewing Society of Japan. Managed by number, starting from No. 1, these strains have been selected one by one from breweries across the country for their superior qualities.

Among them, the oldest strain still in distribution was born in Akita.

Kyokai No. 6. In 1930, it was isolated from the moromi — the fermenting mash of rice, water, koji, and yeast — at Aramasa Shuzo in Akita City. From 1935 it was distributed nationwide through the Brewing Society of Japan, and more than ninety years later it remains in active use. Genetic analysis has led some to call it the “EVE of sake yeast,” the primordial ancestor of the line.

To understand the sake of Akita, this is the right place to begin.

Why an Akita Yeast Was Chosen

Kyokai yeasts are collected from the moromi of breweries that made especially fine sake in a given year. That No. 6 was selected therefore means that Akita, around 1930, was brewing at a standard that stood out nationally.

The character of No. 6 lies in its restrained aroma and its ability to ferment steadily even at low temperatures. It is not a strain that produces explosive fragrance, but it is resilient, and it gives sake a clean, well-defined outline. That character was closely tied to the way Akita brewed.

A Technical System Called “Akita-Style Long, Low-Temperature Fermentation”

No account of Akita’s brewing technology can leave out Hanaoka Masatsune.

Hanaoka arrived in 1918 from the Sendai Tax Supervision Bureau as an engineer for Akita Prefecture, and set about providing technical guidance to breweries across the prefecture. In 1925 he became a full-time prefectural engineer. What he systematized was a method of long, low-temperature fermentation suited to Akita’s climate and conditions.

The thinking runs as follows. Akita’s winters are long and cold. Rather than treating that cold as a disadvantage, use it as the condition that lets you hold the moromi at a low temperature and ferment slowly over time. Fermenting long and cold yields sake with little coarseness and a fine-grained texture. At the same time, it demands a yeast strong enough not to stall in the cold — and it is precisely in this style of brewing that the qualities of No. 6 come into their own.

Hanaoka also worked on yeast handling and on improving koji production, and devoted considerable effort to training toji and brewery workers. In 1927 a brewing division was established at the Akita Prefectural Industrial Research Institute (today the Akita Research Institute for Food and Brewing), and the prefecture’s structure for supporting the technology took shape.

Long, low-temperature fermentation overlaps with the basic principles of ginjo brewing that came later. That Akita turned in this direction at such an early stage still casts its shadow over the character of the sake made there today.

Organizing the Toji

Technology travels through people. In Akita, that role has been carried by the Yamauchi Toji — the guild of master brewers from Yamauchi.

Their origins lie in seasonal migrant labor from Yamauchi Village (today part of Yokote City), where farmers would enter breweries around the country during the agricultural off-season in winter to make sake. In 1922 the Yamauchi Toji Training Association was founded, putting the transmission of technique and the development of new brewers on an organized footing.

The three guilds cited as Japan’s great toji traditions are Nanbu, Echigo, and Tanba; the Yamauchi Toji, for their part, have long sustained brewing within Akita as the guild that represents the prefecture. Technical guidance from the prefectural government on one side, organized training by a toji guild on the other — this two-part structure is what raised Akita’s technical level.

Rice, Water, Climate

Akita is one of Japan’s foremost rice regions, and it has its own sake rice as well.

Akita Sake Komachi, developed in 2001, is a sake-brewing rice that withstands aggressive polishing and is therefore considered suited to ginjo and daiginjo. Misato Nishiki, developed by the prefecture after “Gin no Sei” and “Aki no Sei,” has Yamada Nishiki and Miyama Nishiki as its parents. Akita Komachi, a table rice, is also used for sake at some breweries.

Brewing water comes from subterranean flows out of the Ou Mountains and the Shirakami Mountains. Much of it is soft water, low in minerals, which lets fermentation proceed gently — a good match for long, low-temperature fermentation.

The humidity characteristic of the Sea of Japan side also works in favor of koji making. An environment that never gets too dry allows the koji mold to propagate evenly. Cold, soft water, and humidity: these three conditions underpin brewing in Akita.

Flavor Tendencies

Akita sake tends to settle in a direction that is thick with umami and soft in outline.

The sweetness and savor of the rice come through clearly, and the finish has breadth. It stands in contrast to Niigata, which pushed the light-and-dry style to its limit, and suits drinkers looking for something with substance. Because slow, cold fermentation keeps coarse flavors in check, the sake has body without turning heavy.

Aramasa — The Brewery That Chose the Oldest Yeast Again

Aramasa Shuzo in Akita City is the birthplace of Yeast No. 6.

Today the brewery restricts itself to No. 6 alone. Among the many newer strains that produce showier aromas, it chose to brew solely with the oldest yeast — the one born in its own brewhouse. It has also rebuilt labor-intensive old methods such as wooden-vat brewing and kimoto (a traditional starter method that relies on naturally occurring lactic acid) with modern precision, and with the “No.6” series and others it has updated the very image of sake.

Including its label design and product planning, Aramasa’s work is often described as a reinterpretation of tradition. But there is nothing nostalgic about the substance of it. It is a thoroughly contemporary undertaking: taking a yeast selected in 1930 and getting everything out of it with the technology and sanitation of the 2020s.

Other Breweries and Brands

“Yuki no Bosha” from Saiya Shuzoten is a brewery in Yurihonjo City. No stirring of the mash, no filtration, no dilution — by committing thoroughly to subtraction, they aim to draw out the power of the rice and the fermentation itself. There is depth within the clarity of the flavor.

“Takashimizu” from Akita Shurui Seizo is one of the most widely drunk brands within the prefecture. Reasonably priced with consistent quality, it has become a fixture on Akita tables.

“Kariho” from Kariho Shuzo is a brewery in Daisen City. Known for extra-dry yamahai-brewed sake, it has a following among those who want a sharp, clean finish.

“Ama no To” from Asamai Shuzo operates under the banner “sake begins in the rice paddy,” brewing only with rice from contracted fields near the brewery. It is a brewery built on the idea of narrowing the origin of its raw material as far as it will go.

“Mansaku no Hana” from Hinomaru Jozo is a brewery in Yokote City. Named for the prefectural flower, the mansaku (witch hazel), it has a gentle aroma and a soft flavor.

Pairing with Akita’s Food

The umami in Akita sake meshes with dashi-rich cooking and with fermented foods as accompaniments.

Kiritanpo nabe is a regional hot pot in which “tanpo” — mashed rice grilled on skewers — is simmered in a broth of Hinai jidori chicken. Warm junmai sake goes well with the chicken fat and the soy-seasoned broth.

Hatahata (sandfish) is Akita’s prefectural fish. Beyond salt-grilling, there are many ways to eat it: hot pots made with the fish sauce shottsuru, or hatahata sushi fermented with rice. Warmed sake is what stands up to the strong umami of fish sauce.

Iburigakko is a preserved food made by smoking daikon radish and then pickling it. With its smoky aroma and saltiness, it is about as complete a snack for dry sake as exists. Serving it with cream cheese has also caught on.

The temperature range is wide. Chill ginjo styles to bring out the aroma; warm junmai styles from lukewarm to hot to open up the umami. Much of the sake from snow country shows its true worth warmed.

If You Go

Kawabata in Akita City is the prefecture’s leading dining district, dense with establishments stocking local sake. Aramasa’s authorized retailers include shops in the city.

Yokote City is sake country, home to Hinomaru Jozo and Asamai Shuzo, and also the birthplace of the Yamauchi Toji. During the season of the winter “kamakura” snow-hut festival, the context of snow-country sake can be experienced directly.

Yurihonjo and Daisen also have accomplished breweries scattered through them. Go as far as the Oga Peninsula and a way of drinking built around seafood comes into view.

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Akita sake is the product of a region that translated cold into technique. It systematized a method of fermenting long and cold, produced a yeast that could withstand that method, and has kept using it to this day.

When you drink Aramasa’s “No.6,” what is at work in the glass is a microorganism isolated in 1930. Something selected more than ninety years ago still sits at the center of the flavor — that is the kind of depth of time Akita sake carries.

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For sake from Yamagata, see Yamagata Sake.

For more on kimoto and yamahai brewing, see What Is Nama Sake.

References: Akita Prefecture Sake Brewers Cooperative Association (“Encyclopedia of Akita Sake,” “Secrets of Akita Sake”), the Brewing Society of Japan (Kyokai yeasts), the Akita Research Institute for Food and Brewing, and published information from Aramasa Shuzo