Soy Sauce Suitable for Venerable Expressions

Ishimago Brewery (Yuzawa, Akita Prefecture)

For a soy sauce or miso brewer, the word “old?fashioned” is perfect. And although Yuko Ishikawa, owner of Ishimago, still continues using age?old brewing methods, it doesn’t mean her employees are too: “There are two staff members in their 20s!” jokes Ishikawa?san. However, she is persistent in how she runs her soy sauce brewery, “Even to this day, I still make the soy sauce the same way.” But what I find to be most impressive is how she deals with changing times.

Kojibuta for Soy Sauce Making

Making koji, a naturally occurring mold in soy, is said to be one of the most important elements for soy sauce production. Nowadays, it is common to utilize a machine for quality control, but Ishimago uses kojibuta, or a koji tray. Using the container as a tray, they stack hundreds of koji sheets at one time.

It takes time and effort to load, transfer and unravel the high quantities of koji by hand. There is a funny story where a soy sauce brewer from Ishimago went to a museum and saw the kojibuta being exhibited. They exclaimed, “I always use this at work! [I don’t need to see it at a museum!]”

Preparing the kojibuta for use. The amount shown in the photo will be used.

The kojibuta is then transferred to the mukuro room, where they grow the koji. Charcoal is placed in the hole of the floor, and the temperature is adjusted by opening and closing the ceiling window. Even in the middle of the night, when someone needs to watch and adjust the temperature, they always have to say, “I will go and take care of koji!”

During my first visit, I was quite surprised that they used coal for roasting the wheat. It is quite difficult to obtain coal nowadays. Naturally, the company orders coal from Hokkaido, but they are required to order it by the truckloads.

Kioke?large wooden barrels?for brewing.

The koji is poured until the kioke barrels are full.

Endless walking to and from the wooden barrel

The koji is taken out of the mukuro room, and is transported to 30 kioke barrels (about 5,000 liters or 1,100 gallons). The soy sauce brewers, using two meter high (6.5 feet) wooden pails, walk back and forth transporting the koji until the barrels are filled.

In the kioke barrels, the koji undergoes fermentation and maturation. During this process, a special microorganism develops, which proves to be extremely valuable for the brewer. A nearby research facility sampled the koji, and found that 95% of the microorganisms were unique and different from each other. This number surprised many of the researchers.

Researcher: “These are excellent microorganisms!”
Brewer: “Ah, this soy sauce has a good aroma.”
Researcher: “And this must be the microorganisms’ home!”
Brewer: “Ah! This is the aroma of the warehouse!”

In Ishimago’s long history, the microorganism’s ecological system is unique to Ishimago, which explains the special taste.

A great deal of physical strength is needed to press and refine the soy sauce. Ishimago uses a traditional stone press machine.

Moromi, or the main fermenting mash (unrefined soy sauce), is added into this bag, and squeezed.

With enough strength, it is possible to squeeze all the moisture out, but Ishikawa?san does not recommend it: “It should only be squeezed until it has this thickness and consistency. It should be moist, and not dried out.”

Setbacks due to snowy conditions…

I think it is easy to impress those who see the process of producing soy sauce the traditional way. But perhaps during ancient times, there may be a feeling of inferiority and hardship.

Yuzawa, Akita Prefecture is an area that receives heavy snow, and it usually accumulates on the second floor of the brewing area. It happens so often that half a day’s work has to stop because of the heavy snow. Ishikawa?san thought, “It would be nice to move the koji by machine, rather than by carrying it.” So Ishikawa?san proposed the idea of using machines amongst her team.

But one day, a magazine writer and photographer came to visit Ishimago, and told Ishikawa?san, “We have traveled all over the country, and this traditional brewery is truly valuable. You should leave it!”

The tipping point

“In the beginning, all the snow and traditional methods was exhausting for us. You couldn’t deny that it was difficult to work in these conditions. I kept thinking about switching to newer forms of technology to make production easier,” said Ishikawa?san, “And it seems that we began replacing the buildings and tools with the latest materials or technology.”

“Every year, little by little, we changed something. But now, it is of upmost importance to protect [the traditional methods and tools of brewing].” Now, Ishimago only uses traditional tools for making soy sauce.

After hearing this story, I felt strangely convinced. When I see the tools at Ishimago, I had this feeling that there seemed to be something more important than replacing the equipment and tools. Perhaps this feeling stems from the few brewers who unfailingly continued to use the traditional tools for making soy sauce. A nostalgic atmosphere for traditional brewing methods.

There are no machines at Ishimago


Hyakuju 100ml

If you are familiar with traditional production of soy sauce, then you will be surprised to try the kojibuta method. We are the only factory in all of Japan that continues to produce soy products through this method. Our soy sauce offers a taste that transcends time.

Price: \381 + tax
Ingredients: soybeans, wheat, salt


Ingredients: soybeans, wheat, salt


Misotamari 100ml

Umami, or “savory” taste, is taken from matured miso. Pouring it in a bag with fine mesh, the extract naturally drips into a bottle, creating a clear, beautiful amber color, different from the regular features of soy sauce.

Price: \476 + tax
Ingredients: rice, soybeans, salt



Ishimago Honten

162 Iwasaki, Iwasaki?ji, Yuzawa?shi, Akita Prefecture 〒012-0801
TEL:0183-73-2901  FAX:0183-73-8131