Soy sauce has figured into the cuisine of east Asia for more than two millennia. By that standard, the two-century-old Fueki Shoyu Brewing hasn’t been in the game long. But in running the operation today, Masatsugu Fueki can hardly be accused of failing to uphold tradition: he adheres to just the same practices for making soy sauce (shoyu, in Japanese) as the company’s founders did back in 1879. You can see the entire process in the Eater video above, shot at the Fueki factory in Saitama Prefecture, just northwest of Tokyo. Fueki himself guides the tour, explaining first the sheer simplicity of the ingredients — soybeans, flour, and salt — and then the intricate biological interactions between them that must be properly managed if the result is to possess a suitably rich umami flavor.
That we all know what umami is today owes in part to the propagation of soy sauce across the world. One of the “five basic flavors,” this distinctive savoriness manifests in certain fish, cheeses, tomatoes, and mushrooms, but if you need a quick shot of umami, you reach for the soy sauce. In bottles small and large, it had already become a common product in the United States by the time I was growing up there in the 1980s and 90s.
It must be said, however, that Americans then still had some odd ways of using it: the now-acknowledged Western faux pas, for instance, of liberally drizzling the stuff over rice. But wider awareness of soy sauce has led to a wider understanding of its proper place in food, and also of what sets the best apart from the mediocre — as well as a curiosity about what it takes to make the best.
Fueki and his workers take pains every step of the way, from steaming the soybeans to decomposing the wheat with a mold called koji to heating the raw soy sauce in tanks before bottling. But the key is the kioke, a large wooden fermentation barrel, the oldest of which at Fueki Shoyu Brewing goes back 150 years. Today, Fueki explains, fewer that 50 craftsmen in all of Japan know how to make them: hence the launch of the in-house Kioke Project, a series of workshops meant to revitalize the craft. As he climbs down into an empty kioke, Fueki describes it as “filled with invisible yeast fungus that’s unique to our place” — far from a contaminant, “the most important element, or treasure and our heart.” The care and sensitivity required, and indeed the industrial techniques themselves, aren’t so different from those involved in the making of fine wines. But it surely takes a palate as experienced as Fueki’s to taste “chocolate, vanilla, coffee, rose, hyacinth” in the final product.
Based in Seoul, Colin Marshall writes and broadcasts on cities, language, and culture. His projects include the Substack newsletter Books on Cities, the book The Stateless City: a Walk through 21st-Century Los Angeles and the video series The City in Cinema. Follow him on Twitter at @colinmarshall, on Facebook, or on Instagram.