“Umi no Hishio” (original form of shoyu in the sea), a seaweed-based soy sauce (Photo by Tomoyuki Yamamoto)
When he was discarding the rotten gunk in a sink, Uchida noticed a sweet fruity smell, similar to wine.
“This could be used for something,” the fisheries researcher recalled thinking.
From that gut feeling came a new type of soy sauce whose main ingredient is seaweed, not soybeans and wheat.
But it was a long time in the making.
The seaweed have been placed in a fridge in his laboratory in Yokohama about 20 years ago after he used it in experiments.
Uchida’s long-held goal was to find an everyday use for fermented seaweed.
In 2002, Uchida was transferred to the Fisheries Research Agency (FRA) of the National Research Institute of Fisheries and Environment of Inland Sea (FEIS) in Hatsukaichi, Hiroshima Prefecture.
He picked seaweed, a specialty of the Seto Inland Sea, as an ingredient for his study on fermentation.
After a great deal of trial and error to curb the propagation of bacteria, Uchida finally found a method to ferment seaweed with natural micro-organisms, which resulted in “nori shoyu” (seaweed soy sauce).
Uchida tasted the seaweed-based soy sauce he made in his laboratory. Although his shoyu was relatively weak compared with that of the general soy sauce, a distinctive “umami” savory taste lasted for a long time in his mouth.
He named the sauce “Umi no Hishio” (original form of shoyu in the sea).
The FRA turned nori shoyu into a commercial product in 2017 in tandem with soy sauce makers and other entities in Saga Prefecture.
In consideration for those who suffer from food allergies, bottles of nori shoyu carry a label that reads: “soybean free, wheat free.”
“I want to build a brand new food culture with fermenting seaweed, just like ‘gyosho’ fish sauce, which was made through the fermentation of fish,” Uchida said.