Carefully climbing the steep stairs, I followed Tsunenori Kano to the attic of his family’s soy sauce fermentation room, called Kadocho, which is 180 years old.
The dark space was eerily quiet except for the creak of my footsteps on the old wooden boards placed between the vats of soy sauce.
The sauce was dormant now, since it’s late winter, but it still filled the air with a savory aroma. Around me, a thick fungus-laden crust covered the ceiling, clung to the rafters, and grew up the walls.
“Those are the bacteria and yeast that are as old as the building,” Kano, the seventh-generation fermenter, told me. “They provide the authentic flavor.”
I was in Yuasaa quiet port tucked away in a bay on the western coast of Wakayama Prefecture’s Kishu Peninsula, on a quest to learn about the ancient origins of Japanese cuisine’s holy grail: soy sauce.
Tamari
Soy sauce is possibly the most important condiment in Japanese cuisine. Its well-balanced sweet and salty flavor and deep layer of umami richness make almost any food taste more delicious and satisfying.
Tsunenori Kano comes from a family of fermenters.
Its uses range from topping sushi to a splash in noodle soups and stir-fries, as well as the signature flavor of glazed dishes like teriyaki.
In 2017, the Japan Agency for Cultural Affairs designated Yuasa a Japan Heritage Site for being the birthplace of soy sauce, which is said to have been first made here in Japan. at the end of the 13th century.
The now-beloved condiment emerged shortly after a japanese buddhist monk called Shinchi Kakushin returned from a trip to China and became abbot at Kokoku-ji temple near Yuasa.
He brought with him a recipe for making Kinzanji miso, an exceptionally thick type of miso made from whole soybeans, various other grains (such as barley and rice), and vegetables.
The townspeople of Yuasa soon discovered that the small amounts of liquid that collected in the fermentation vats of Kinzanji miso, as its ingredients were pressed with heavy stones, were delicious in themselves.
This byproduct, called tamari (a generic word meaning “to accumulate”) became the soy sauce base as we know it today.
soy sauce center
In a matter of years, Yuasa has grown from a way station on the Kumano Kodo pilgrimage route that leads to the famous temples and shrines of nearby Mount Koya to become the most important soy sauce manufacturing center in Japan.
Kinzanji miso remains a popular delicacy.
In its heyday, the small town of just 1,000 houses was filled with more than 90 soy sauce fermentation sites, nearly one soy sauce shop for every 10 households.
Today, the city’s historic district is protected by Japanese law. It is a vast area encompassing 323 houses and other hongawara-buki (traditional buildings) recognized for their immense cultural value.
Many of them still retain their traditional barred windows and curved tile roofs, architectural features that were symbols to passersby of their owners’ prosperity.
There is five soy sauce shops and six Kinzanji miso makers that are still active. Visiting them tells the remarkable story of the intertwined fortunes of Kinzanji miso and soy sauce.
origins
The distinctive flavor of Yuasa soy sauce reflects its ancient origins, from the Miso Kinzanji.
Unlike other types of miso, which are pastes used as condiments, Kinzanji miso is a nutritious dish with an elegant taste.
The liquid that remained after the fermentation of the Kinzanji miso was transformed into soy sauce.
It is a culinary relic of Song dynasty cuisine, considered one of the world’s great culinary developments when exquisite new flavors were created from ordinary ingredients, and has remained a popular local delicacy throughout the centuries, enjoyed as a snack, side dish, or even a light meal when added to a bowl of rice or mixed with chagayu (a porridge made from rice, water, and tea).
It was served to me at every meal while at Yuasa.
Because their tamari byproduct was so tasty, the locals wanted a way to produce it in larger quantities.
They efficiently adapted the Kinzanji miso-making process to create soy sauce, a lighter but similar-tasting form of tamari.
Adaptation process
Established in 1841, Kadocho is one of the oldest soy sauce factories in Yuasa; the sauce they produce is as close to the original kind as you’re likely to find anywhere in Japan.
Most of the process is done manually.
As we descended from the loft, Kano explained how the soy sauce making process was adapted from Kinzanji miso.
Pointing to ancient wooden tools and iron equipment, he said making soy sauce uses just two grains, rather than one variety – steamed soybeans and roasted wheat – which are mashed rather than left whole (as is the case of Kinzanji miso) to better extract its flavor and umami.
They are then mixed with koji-kin (green mold Aspergillus oryzae spores), as is done with Kinzanji miso, and left for three days in a closed roomcalled a wall, where the temperature is carefully controlled.
There, the grains germinate and their starches are converted into sugars, allowing fermentation.
This mash is then placed in wooden barrels filled with plenty of fresh, salted water – instead of the watery vegetables used for Kinzanji miso – and the brew is fermented for at least 1.5 years so that it takes on the same kind of smooth and complex flavor that Kinzanji miso has.
Yuasa.
Kano, a powerful-looking man, says that much of the work is done by hand. This includes regularly mixing the mash in their 34 large barrels with long wooden paddles and squeezing the soy sauce from the mash when ready.
Lastly, Kano slowly heats the soy sauce in an iron cauldron for half a day to stop its fermentation, using pine wood for the fire.
Variety of Microbes, Diverse Flavors
only around the one% of the soy sauce produced in Japan by some 1,200 companies is still made in the traditional way using wooden barrels, according to Keiko Kuroshima, a soy sauce inspector and evaluator.
One of Japan’s three self-styled soy sauce sommeliers, she is the author of the definitive guide to soy sauce Shoyu Hon (Soy Sauce Book), published in 2015.
“Other soy sauce is mass-produced in stainless steel tanks with the goal of creating a consistent flavor in the shortest amount of time, often using artificial means to speed fermentation,” he says.
“The wooden barrels help create a greater variety of flavors due to the microorganisms that live in them. They also better reflect the skills of the fermenter, as they are more involved in the process.”
Kadocho’s soy sauce, whose flavor is characteristic of soy sauces made at Yuasa, has a thick body and a rich, powerful flavor, yet is pleasantly aromatic and smooth, like well-aged cognac.
Its flavor partly reflects Kano’s use of a higher proportion of high-protein soybeans and wheat than the industry standard.
Traditional soy sauces have a greater variety in their flavor.
Most fermenters, even traditional ones, use a ratio of 50:50 of soybeans and wheat, which produces a lighter sauce with a lighter flavor.
Kubota Soy Sauce Fermenter, another former Yuasa establishment, produces two types of soy sauce. One, I was surprised to learn, is made with up to 80% soybeans and only 20% wheat.
The other, matriarch Fumiyo Kubota told me, is their “light” soy sauce. It is made with 70% soy and 30% wheat. When I passed by, she was busy preparing koji, the mixture of koji kin, soybeans, and wheat, in preparation for a new batch of soy sauce to be made over the next 1.5 to two years.
Competition
The number of Yuasa soy sauce producers has drastically decreased over the last century. The main factor is competition from industrial producers “who compete mainly on price given the standardized quality of their soy sauce,” according to Kuroshima.
Traditionally made sauce is about two to three times more expensive than industrially produced sauce. “The competition is so intense that it’s not only putting traditional fermenters out of business, but also industrial producers in recent years,” he explains.
One man bucking this trend is Toshio Shinko, who is working to restore Yuasa’s position as a leading soy sauce maker.
He is the fifth-generation director of the miso maker Kinzanji Marushinhonke, a business started by his great-great-grandmother in 1881. In 2002, Shinko created Yuasa Soy Sauce located in an elegant new building on a hill overlooking the city.
His goal, he says, “is to make the best soy sauce in the world” by combining the best possible ingredients with ancient techniques, such as the use of wooden barrels, along with new production methods.
Soy sauce is used in a wide variety of Asian dishes.
His featured soy sauce, called Kuyo Murasaki, includes a special ingredient: some of the rare tamari byproducts from his family’s Kinzanji miso.
Shinko has also created a line of specialty products, including organic and halal soy sauce, to ensure the condiment’s place on the table for years to come.
Yuasa’s official recognition as the birthplace of soy sauce has revitalized the community, promising more soy sauce variations and uses.
To celebrate this exciting future, before I left Yuasa Soy Sauce, I stopped by their cafe and bought a cone of their delicious soy sauce ice cream.
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