Sake’s surging popularity in the United States and Europe has made it easier than ever to find standout bottles beyond Japanese shores. But at home, sake-drinking has been in decline for decades. Nowadays, Japanese consumers prefer beer, wine and cocktails over the national drink, and the country’s brewers are producing less than a fourth of their peak annual sake output of 1.7 million kiloliters (about 450 million gallons) in the early 1970s. Nothing seems to reverse the trend—not the recent explosion of new types, from fizzy to barrel-aged, or even rising sake exports. And yet the revival of a centuries-old, traditional style has brewers guardedly optimistic about sake’s future.

Earlier this year, in June, Japan’s Heiwa Shuzou brewery opened a concept sake bar and bottle shop in downtown Tokyo. It was an unusual, but not entirely unexpected, foray for the 94-year-old, family-run brewery based in Wakayama. Two years prior, Heiwa Shuzou went from obscurity to stardom when it was crowned the International Wine Challenge’s Sake Brewer of the Year. The IWC judges bestowed best-in-show honors on the brewery’s Kid Muryozan Junmai Ginjo sake, praising its “linen-like texture,” melon-persimmon-pineapple flavor and sanshō pepper finish.

Heiwa Shuzou’s award-winning sake, however, isn’t the focus of its new bar. Instead, the brewery wanted to reach beyond its usual fan base with the rebrand of a rustic drink: doburoku, a soupy, cloudy sake that many in Japan have heard of, but few have ever tasted. 

At Heiwa Doburoku Kabutocho Brewery, the drink comes plain or aged, but also with unusual variations: dry-hopped, infused with matcha, mashed with persimmons, or blended with azuki beans, in part to tone down the alcoholic sharpness that many among sake’s detractors find off-putting. Fermenting the base of rice, koji fungus and yeast takes about two weeks, and most of the doburoku is made in 7-liter pots in a backroom of the bar, says Norimasa Yamamoto, Heiwa Shuzou’s fourth-generation president. By putting a modern spin on the old-fashioned drink, and by emphasizing that most of it is made by the bar’s staff, Yamamoto is trying to renew interest in sake as a whole. “I’m hoping that, once you’ve tried doburoku, you’ll become curious enough about our rice fermentation tradition to delve into sake,” he says. 

“Doburoku” is a catch-all term for sake that’s unfiltered and gently carbonated. It’s widely considered the primeval sake, predating techniques that spawned the now-familiar clear, filtered version of Japan’s national drink. Across the archipelago, farmers have been making doburoku for as long as they have been growing rice—possibly as early as 3,000 years ago when the grain was first brought from China, according to Toshiaki Yamada, president of the Sake Culture Research Institute.

Doburoku’s hyperlocal expression of soil and culture is its trademark. Typically, it was unpasteurized and brewed in such small batches that you could only get it from the person making it. Unlike conventional sake (nihonshu), which has rigid rules about ingredients and provenance, doburoku has no strictly defined characteristics, which means there’s a lot of leeway for experimentation. Versions can be as sweet as rice pudding, or as sour as yogurt; others are reminiscent of honeydew melon or olives. It can be lumpy, gritty, muddy or smooth.

With doburoku, it’s pointless to compare tasting notes on a sake matrix—measuring sweet to dry and light to acidic—or recommend food pairings, because the drink’s flavor is constantly in flux, according to Chikako Ohkoshi, a veteran sake educator and founder of the Doburoku Lovers Association. “Open a bottle and large bubbles will rise out of the top. It’s still alive and fermenting and changing,” says Ohkoshi. “You can’t make a tasting matrix for a drink like that.”

Today, only roughly 200 brewers produce doburoku, the majority being farmers who also run mom-and-pop inns and restaurants. About two dozen of Japan’s 1,500-plus sake breweries have entered the fray, alongside a band of so-called “craft sake” startups led by young toji (master brewers) who are applying their expertise to exploring the drink’s potential. 

But before politics and taxes nearly killed off doburoku more than a century ago, every household in mountain hamlets and rural seaside towns seemed to have its own recipe and brewing method. After the government outlawed home-brewing in 1899 to protect the sake industry—which, in turn, boosted tax revenues that funded a military buildup—doburoku-making went underground. Takuo Nakagawa, head brewer of Doburoku Taku in Niigata prefecture, recalls how families in the farming village where he grew up were too poor to buy liquor. “Everyone made and shared doburoku. It unified our community. When the tax authorities raided suspected home-brewers, we worked together to alert everyone to dump or hide their doburoku,” he says. Only Shintō shrines, which served doburoku as an offering to the gods at their annual harvest festivals, were granted special permission to continue producing it. 

Nakagawa, who now grows rice on 350 acres of terraced fields, was among the first wave of farmers to sign up for a doburoku-brewing license that the government created in 2002 as part of sweeping reforms. For Nakagawa and other former bootleggers like him, it was an act of historical reclamation, a way to introduce a bit of local lore about a hidden past. For Japan’s sake industry, it has provided a rare glimmer of positive news. 

The government hasn’t issued any new brewing licenses for filtered sake in decades, but opening up the market to doburoku gives a younger generation of brewers a chance to showcase their talents. The opportunity led 34-year-old Shuhei Okazumi to start Ine to Agave, a brewery in Akita prefecture, last November. For now, his license is only good for making doburoku and a type of clear sake—with additives like agave, barley or hops—that’s not considered nihonshu. He’s meticulous about his ingredients, growing or buying only organic rice, and passionate about paying farmers at prices several times higher than the market. And his brewing methods are just as rigorous as the country’s most renowned sake labels: Okazumi makes his own rice koji and yeast starter, and uses medieval, labor-intensive techniques (such as naturally cultivating lactic acid bacteria) that take great skill and much time but result in deeper, more complex flavors. To remove the stigma of the drink as little more than a farmer’s brew, in June Okazumi formed a coalition with five other doburoku startups, called the Japan Craft Sake Breweries Association. 

Eventually, he hopes to teach and recruit more young brewers to the coalition and build a movement that extends to every part of the country. “We want to show how surprisingly good doburoku can be,” Okazumi says. “We want to convert people who assume they can’t stand sake.”