Cultivated Days | The Shoyuya
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The Shoyuya

The Shoyuya

A young soy brewer earns his title

Yoshinori Joh came of age in Itoshima, 30 kilometers west of Fukuoka, on Japan’s southwestern island of Kyushu. It’s where he was born, and where his father ran the family business making soy. Or so he had always thought. They called themselves shoyuya, soymakers, but in his mid teens Joh was shocked to learn that his father didn’t actually make soy. He purchased namajoyu (unprocessed soy) in bulk. All the busyness that Joh had witnessed growing up in the family brewery was the not the making of soy but rather the processing of soy. His father would blend the sugary additives that give Kyushu soy its characteristic sweetness and then bottle it under the family company’s name, Mitsuru. For nearly half a century this had been the common practice among shoyuya around the country, a system implemented to centralize and streamline a laborious process.

Joh was alarmed. “How can we call ourselves shoyuya when we don’t actually make soy?” he worried. The mendacity of the claim nagged at him. As he grew older and closer to assuming control of the business, he knew he couldn’t operate under the same pretense. To work as a shoyuya, he would have to make his own soy.


Japan’s food culture is at its core a fermented food culture. The five most common seasonings used in Japanese cooking, soy, miso, vinegar, sake, and mirin, are all fermented foods. The process of fermentation is responsible for that celebrated savory Japanese flavor known as umami. For centuries fermenting was the necessary means of preserving foods through hot summers and cold winters and Japan’s wet climate is well suited to fermentation.

Soy in Japan, like salt in the west, is ubiquitous. Broadly speaking, regional soy preferences divide the country. Cooks in the western Kansai region (Kyoto and environs) favor the lighter, amber colored soy known as usukuchi. Thinner in flavor and color, it imparts a salty umami without staining the clear broths and bright vegetable colors that define the regional dishes. To the east in the Kanto region (Tokyo and environs) the rosewood colored koikuchi is preferred for its fuller bodied earthy flavor. And then, in a category all its own, there is the sweetened soy of Kyushu, the soy that Joh knew growing up.

To prepare for his role as a shoyuya, Joh left for Tokyo to pursue an agricultural studies degree with a focus on fermented foods. He had it in mind to continue producing the sweet soy of Kyushu but to find a natural method to replace the need for sugary additives. He experimented with adding amazake (a sweet fermented rice drink), or starchy components but nothing resulted in soy sweet enough to satisfy the Kyushu palate. In those same years, while studying in Tokyo and then in Osaka, he slowly learned to appreciate the more balanced flavor of unsweetened soy.

When Joh returned to Itoshima in 2009 he had abandoned the idea of making Kyushu’s sweet soy. His single focus was to make pure soy using traditional methods. Beyond that, he had no particular designs on the outcome. Before he could articulate any specific ideas about taste, he first had to succeed at making soy from scratch. It would still take a couple of years to set up and invest in the required equipment, and a couple more to ferment the first batch. “I was nervous the first time,” he said. In February of 2013 he pressed his first soy.


This is Joh’s 6th season making soy. He runs Mitsuru with a team of 7, all of them family members. While most commercial soy production relies on shortcuts and additives to simplify and accelerate production, Joh remains committed to working with exacting traditional methods. Each winter he makes a new batch of soy. Soybeans are steamed for 5 hours and then mixed with equal parts roasted cracked wheat. To this Joh adds Aspergillus mold. This mixture, known as koji, is set in pallets in a warm humid room for three days. Each day Joh must work for hours in the heat mixing and turning the koji to facilitate the mold’s growth. The koji stage is rigorous and requires near full time care and attention as it most directly impacts the final flavor.

After three days, the koji is moved into enormous wooden fermentation barrels and mixed with salt and water to make a mixture called moromi. Moromi is a living entity, a growing and evolving mixture of organic compounds that Joh must continually monitor throughout the year. The wooden barrels themselves are an asset, a matrix of beneficial bacteria that encourages the moromi’s development. Initially thin and light beige in color, over time the moromi turns rich brown, thick, and bubbly.


Good soy has an even balance of five flavor characteristics, umami, saltiness, sweetness, acidity, and bitterness. As the moromi ferments, proteins in the soybeans are broken down to produce umami rich amino acids while the wheat starch is converted to glucose that gives soy sweetness and fragrance. As amino and lactic acids build up, they suppress the intense saltiness of soy, nearly 6 times that of seawater. Acidic and bitter elements emerge that, though not immediately observed in the taste, serve to lighten, clarify, and amalgamate the flavor.

Joh has proven that he can make good soy from scratch but admits that he is still trying to better understand the process. Each year he makes small adjustments to see what affect it has on the flavor. “The level of amino acid was low that first year,” he recalled. “It’s much better now, it has more umami.” But it’s a slow process. Each batch of soy is 300 kilos and must age over the course of at least two summers. Results are slow to come in.


Joh, like others of his generation who came of age after Japan’s economic bubble burst, is disinterested in climbing the proverbial ladder, in finding the quickest, easiest path to success. He takes great satisfaction in working with his hands to make tangible goods. Though his father has offered assistance in the form of loans for equipment, it’s been hard to bridge a gap in ideology and there has been little exchange between them about Joh’s pursuits. And marketing his pure, unsweetened soy in Kyushu has been challenging. The locals who bought his father’s sweetened soy for years are hard to convince.

But Joh persists, fueled by a passionate need to earn his title as shoyuya. On one of my final visits, I found him preparing to press a three-year-old moromi. He described how the flavor had mellowed a bit in the third year, the saltiness rounding out into a fuller, sweeter flavor. As he filled bags with moromi and laid them in rows in a stainless steel tank, the pressure of the bags themselves sent a steady stream of soy thorough a spigot into a holding tank. Joh pulled back the plastic cover and let me try a taste. It was a lovely caramel color, the taste fresh, a perfect salty umami balanced with an earthy fermented aroma. He’ll heat this new soy once to unlock more of its fragrance and then bottle it, no extra sweeteners, no preservatives.

Joh likes soy with a soft start and a lingering finish. “Soy shouldn’t have a strong initial impact,” he told me. And more than the flavor of the soy itself, how it interacts with other flavors occupies his attention. “It should be gentle.” Joh always keeps in mind that soy is never used as a standalone ingredient. It sings harmony, its breadth and depth blending to compliment other flavors. It should never call attention to itself but be surely missed if absent.

Joh calls his soy 生成り, (kinari, comma included) and always stamps the year it was started on the label. The comma signifies an intermission. Each batch of soy is a pause in Joh’s ongoing conversation with his ingredients and process.


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