Traditional sake brewing is best in winter

Traditionally, sake is brewed in winter. This isn’t just because the process begins shortly after rice is harvested. Rather, it’s because the fermentation process works best at constant cool temperatures (ie, below 15C). Perhaps for this reason, the Japan’s snowy Tohoku region is thought to produce some of the best sake in the country.

A great place to check out winter sake brewing is Yonezawa in Yamagata, situated on an alluvial plain surrounded by mountains. At the Toko Sake Museum, housed in brewery complex more than a century old, visitors can see for themselves how sake was produced in the pre-industrial era and finish their visit by sampling some of the current Toko sakes.

The front of the main building is where the brewery owner and his family once lived, with one room operating as a store front.

Step on through to the brewery, behind the residence, and really step back into the past. The first room displays the various tools and wooden containers required to produce sake.

A large illustration on the wall shows all of the steps in traditional sake production: polishing and washing the rice, steaming it, spreading it on trays to cool and then sprinkling it with koji mold, producing mash, fermentation, and pressing.

In our modern times, filtering, pasteurizing and bottling complete the process.

Massive wooden fermentation barrels are still lined up in the fermentation warehouse. Sake would have fermented in these barrels for anywhere from two weeks to two months. Since the warehouse is now the centerpiece of the museum, in addition to the fermentation barrels, it also contains displays of more wooden tools used in sake production, including the massive wooden fune used for pressing the sake out of the fermented mash, one of the final steps of the sake production process. The number and variety of antique wooden equipment on display is impressive.

Just beyond the fermentation warehouse is the koji-shitsu, where, in one of the earliest stages of the sake production process, the cooked rice, spread on trays and sprinkled with koji mold, sits in a warm, humid environment while the mold grows on the rice to begin the process of converting the starch in the rice to glucose. This is an essential step to producing delicious sake.

At the end of the tour, visit the tasting rooms to sample Toko Sake. There is a large tasting room as well as a smaller, more intimate, space overlooking a garden. At one end of the large tasting room a pump dispenses the sweet water used to produce Toko Sake, which visitors are also welcome to sample.

Kojima Sohonten Co., Ltd. has been producing Toko Sake since 1597 and was once the sake brewer for the local feudal lords. Even the name Toko, which means “Eastern Light” has a special association with the orientation of Matsugasaki Castle, the former seat of the Uesugi lords and now the site of Uesugi shrine.

The current proprietor of Kojima Sohonten, Kojima Kenshiro, is the 24th generation head of the brewery. He is dedicated to producing world class sake to delight anyone who drinks. A shop selling Toko Sake and various sake accoutrements is next door to the tasting rooms.

The Toko Sake Museum is open daily from 9:30 am to 4:30 pm. Admission is JPY350 for adults; JPY250 for children.

I was fortunate during my visit to get a specially-arranged tour of Kojima Sohonten’s working brewery, a few blocks from the museum and not usually open to the public.

There I got to see the modern processing in action.

It was especially interesting to see the “test” fermentation barrels, small barrels at different stages of fermentation watched to judge how well fermentation was taking place in the primary vats. Sometimes if a batch isn’t fermenting as desired, more molded rice is added to the mash. And, of course, the longer the mash ferments, the foamier it gets.

The primary vats of fermenting mash are manually stirred from time to time. While this process isn’t necessarily dangerous, falling into a vat would be fatal, due to the high levels of carbon dioxide produced by the fermentation. Needless to say, precautions are taken.

Seeing both the traditional/historic sake production methods and modern brewing, as well as sampling a few Toko Sakes was a highlight of visiting Yonezawa.

©2022 and Vicki L. Beyer
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