I was at a small izakaya in Niigata on the west coast of central Japan, and the sake was flowing. In between bites of mackerel and big, pink, nearly translucent shrimp pulled from the Sea of Japan, we drank several bottles from in and around Niigata. Bottles of junmai daiginjo and junmai ginjo seemed to almost empty themselves, but thankfully I was with a group that always knew what to order. At one point as I put my chopsticks down, the man seated to my right looked me dead in the eye and told me, “I want to change the world with fermentation.”
It’s perhaps not the kind of thing that is typically said between grown men while eating, but we’d had a considerable amount of sake by that point and he meant it. Satoru Furuta, the next-in-line toji—master brewer—at the nearby Imayo Tsukasa sake brewery, envisions a better world if everyone incorporated more fermented products into their lives.
Fermentation is the beating heart of all brewing, an art to which Satoru has dedicated his life. In sake brewing, after rice is milled to remove its outer husk—to get rid of the grain’s tougher exterior—and washed and steamed, a mold called koji is spread upon a portion of the rice. The koji breaks down starch molecules into sugar molecules in preparation for the addition of yeast, which is otherwise unable to break down rice. That koji-inoculated rice is then mixed in a tank with regular steamed rice. Yeast is added, and fermentation largely takes care of the rest as the yeast eats the sugar and converts it into alcohol. After extracting the liquid from the mash and filtering it, you are left with sake.
Brewers manipulate the process in any number of ways, using different kinds of rice or yeast or choosing to mill the rice to various degrees, to name but a few. Working with and around fermentation, they craft unique expressions of sake—from the wild and pungent barely filtered nigoris to effortlessly elegant junmai daiginjos, the Rolls-Royces of sake.
“I first became interested in sake brewing while browsing a magazine in a convenience store while I was unemployed,” Furuta told me. “There was a special article about sake making, and I thought, Cool! This is what I want to do!”
Furuta began working at a brewery called Kanemasu in his hometown of Shiibata, learning the intricate sake making process. After three years, though, he was laid off as the brewery struggled. He followed a job lead and ultimately landed at Imayo Tsukasa in Niigata City, which wasn’t very well known at the time but has now grown in its reputation. The sakes produced at Imayo Tsukasa are excellent, refined and subtle sakes that give way to more depth and character with each sip and as they change temperatures. About five years ago, as Furuta progressed up the ranks, he began to think of ways to use fermentation outside of the context of sake.
The Japanese take fermentation seriously. Koji, the key agent in sake fermentation, is unofficially considered the “national fungus” of Japan. It plays a role in nearly every meal—it’s a crucial ingredient in soy sauce, miso, and mirin, and other ubiquitous foods like breakfast pickles or gari (pickled ginger). Rarer and bolder items like black garlic or the legendarily stinky kusaya fish are fermented, too. And then there is natto, a famously smelly soybean breakfast dish that sake brewers are forbidden to eat—if some of the enzymes from natto were to make it into the brewery, say, on a brewer’s clothes, it could interfere with sake fermentation.
Having spent about a decade tinkering with the sake brewing process, Satoru has become a master of fermentation. On Facebook, he calls himself a fermentation samurai. He now experiments with fermentation at home, adding Japanese twists to Western foods.
“It is fascinating how fermented goods walk a fine line of effects on the body,” Furuta said. “If they are skillfully produced, they have a positive effect on the body, and if they are carelessly made, they will have a negative effect.” You can use your imagination as to what those “negative effects” might be.
He has created fermented rice ketchup, which is white rather than red, and its applications extend beyond fries and burgers. It tastes something like tomato ketchup, but not really. He envisions using it to make “Hinomarita pizza,” the name of which is intended to call to mind Margherita pizza. It’s a double pun: Hinomarita is the name of the rising sun on the Japanese flag that, Satoru points out, looks a bit like a pizza. He also plans to create his own version of “Napolitan” spaghetti, a popular Japanese dish with a convoluted backstory that Satoru will further complicate. Napolitan spaghetti is named for Naples, and is made with ketchup and vegetables, a concoction dreamed up by a Japanese chef who was inspired by American military rations from World War II. Satoru will use white ketchup and will call it “Japolitan.”
He’s still tinkering with those. For now, he’s willing to share his take on a Bolognese ragu that uses a miso-based sauce to create a decadent pasta dish bursting with umami. He calls it Nutarian, named for a port town on the river outside the Imayo Tsukasa brewery that used to ferry sake barrels to Russia and down to all points south.
Furuta’s passion for fermentation has caught on at Imayo Tsukasa. The brewery also produces amazakes, fermented rice beverages with no yeast added, meaning they contain no alcohol. Amazakes are naturally sweet and rich in live cultures, making them good for the digestive system, like yogurt. But Furuta has added a twist, and has earned a patent for his creation.
It goes like this: Toward the end of the sake brewing process, after rice, water and yeast have fermented in large tanks for a couple of weeks, the resulting mash is pressed, squeezing out sake and leaving behind a dough-like substance made from rice. This substance, known as sake lees or sake kasu, is rich in vitamins and minerals, and, more importantly, malic and lactic acid. Furuta adds sake lees to an amazake, giving the drink a sour, yogurt-like flavor and boosting its nutritional value. It can be used as a substitute for milk in cooking, makes a mean potato salad, and works as a mixer to make sake cocktails.
Furuta wouldn’t go into the details of some of his creations, some of which, like the rice ketchup, he has big plans for. But the way in which he considered the possibilities of fermented foods was eye-opening. Could we eat better by tinkering a little with some seemingly mundane dishes? Much of the world already does, out of necessity and tradition. But whether it’s farmers pickling vegetables for the winter, fishermen brining fish and packing them away in barrels, or Michelin-starred chefs experimenting in stainless steel kitchens, all loosely hold the reins to a transformative process with feet planted in both biology and culinary art.
At dinner in Niigata, with the help of an American friend acting as an interpreter, Satoru asked the table if he could read a poem, a sort of treatise on the state of mind with which he thinks about brewing and fermentation. He stood, and began to tell about the wonders of fermentation and how, at his brewery, he and his fellow brewers work to share the fruits of fermentation.
“In short, what can be obtained by fermentation is beneficial for humans and may be said to give pleasure to everyone,” the poem read. “We are invigorated by the joy of brewing. This is the attraction of brewing for us, and as long as this spirit persists, we will not be corrupted.”
Later on, Furuta expounded further. He told me how when he ferments sake or food, he isn’t just making something to be consumed. Rather, he creates things that he hopes will stick around for some time longer in spirit.
“One of the positive effects I have seen in the study of fermentation is happiness,” he told me. “Therefore I conclude that skillfully crafted fermentation is not only good for the body, but also the soul.”