The Story of Dassai Sake From Otter Festival to Outer Space: Kazuhiro Sakurai Tells Us How Dassai Out-polished, Out-planned & Out-travelled Every Other Sake

Mr Kazuhiro Sakurai, the current president and the fourth generation owner of Dassai Inc.

 

There is a room inside Dassai's brewery where brewery staff work every single day of the year. The room runs on rotating shifts through the night and straight through New Year and every other public holiday in Japan. It is also is kept at close to 30 to 40 degrees Celsius, the air often thick with the smell of hot steamed rice with a team of four workers drawing thousands of kilograms of rice through the room and judging its progress by touch and eye. They have to. The living thing growing in that room does not keep office hours.

This room is the koji room, and koji is where sake really begins. To make it, steamed rice is dusted with the spores of a mould called koji-kin (Aspergillus oryzae) and left to grow for about two and a half days, until each grain is threaded with enzymes that can break the rice's hard starch into sugar (necessary for alcohol fermentation). Most large breweries now grow their koji with the help of machines. Dassai makes all of the koji for its top sake by hand, judged by touch and by eye, which is why someone is always awake with it. If you pass an employee with red eyes, the koji maker might have been up all night.

 

Brewery workers in Dassai's all-important koji room (Image Source: Dassai)

 

Traditionally sake usually reaches the consumers wrapped in mystique: a master brewer reading the mash by instinct, know-how handed down through apprenticeship and never written down. But Dassai's most revealing object is its meticulous tracking of the brewing process on a single chart that looks like a hospital chart for a sake batch. It is the day-by-day medical record of one tank of fermenting rice, every reading plotted against an ideal curve the brewery has refined over years and dated like a piece of software. Dassai hasn’t had a traditional master brewer since decades ago. In its place, the brewery uses intensive data and brewing science.

Those two instincts, the handmade and the measured, add up to the most recognised sake in the world. Dassai Sake’s brewery is hidden in the mountains of Yamaguchi, at the far western tip of Japan's main island, and it now sells in more than thirty countries. In 2021, Dassai alone is reckoned to have made up around 17% of all the sake Japan exported.

 

 

At this year’s Sake Festival Singapore, I spent attended the masterclass led by company's fourth generation owner and current chief executive, Mr Kazuhiro Sakurai. What follows leans on that hour, and on two glasses of sake we had the opportunity to taste. Here’s the story of how a brewery hidden in the mountains came to become the biggest brand in sake today.

A brewery hidden in the mountains

Many of Japan's celebrated sake breweries had started with built-in locational advantages. Dassai started with none of that to lean on. The modern, data-driven operation grew out of one of the least likely places in Japan to build a global luxury brand. Everything it is known for, it built in this quiet mountain valley from craft rather than inheritance.

 

Who would have thought a sake from the mountainous Yamaguchi Prefecture, not known for its sake making, turned out to be sake's biggest hit. (Image Source: Dassai)

 

Dassai hails from the former Osogoe district of Shuto-machi, in Iwakuni City, at the eastern edge of Yamaguchi Prefecture. To reach it you drive about thirty minutes up into the hills from Iwakuni proper, along a narrowing river valley, until the road runs short of towns. This is deep countryside. It is said that the local elementary school near the old brewery at one point only had a grand total of nine pupils.

 

  

The name “Dassai” itself comes from the valley. The brewery is located in Osogoe, written with the character 獺, meaning “otter”. Dassai, written 獺祭, literally means “otter festival”, an ancient expression inspired by the way otters were said to arrange their catch along the riverbank as though laying out ceremonial offerings. The phrase later came to describe a writer surrounded by books and reference materials. It was adopted by the Meiji-era poet and literary reformer Masaoka Shiki, who called himself Dassaishoya Shujin, or “Master of the Otter-Festival Book Room”. Asahi Shuzo, as the brewery was then called, named its premium sake after Shiki’s spirit of literary innovation.

 

 

Most sake breweries are low, sprawling, single-storey affairs. Since 2015, Dassai has been operating a twelve-storey brewery on the same mountain hollow that stands like a tower rising out of a crease in the hills. A tall building lets Dassai move rice downward through the floors as it passes from milling near the top to pressing lower down, using the layout itself as part of the process (two floors of the brewery were given over to large koji rooms).

Betting the brewery on only the very best

Dassai the sake is younger than the company that makes it. The brewery was founded in 1948 as Asahi Shuzo, and for its first few decades it made mass market sake for local consumers. The turn came in 1984, when Hiroshi Sakurai, the third generation of the family and today the company's chairman, took charge. The regional sake market was shrinking and crowded, and rather than fight a price war at the bottom, Hiroshi made the opposite bet: his company would now produce only the highest grade, junmai daiginjo. In 1990, that new direction acquired its defining name: Dassai.

 

 

Japanese sake is ranked partly by how much of each grain of rice is milled away before brewing. Polish off at least 40% of the grain and the sake may be called ginjo; polish off at least 50%, and it qualifies as 'daiginjo', the top rung. 'Junmai' means pure rice, with no distilled alcohol added to the brew. Junmai daiginjo therefore sits at the very top of the formal hierarchy: pure-rice sake from heavily milled grain. Choosing to make only the most costly category, in a market where all sake producers were struggling, was close to contrarian.

Hiroshi then paired that decision with a second one, just as absolute: Dassai would be made from a single variety of premium rice, Yamada Nishiki, and nothing else. More on that shortly.

 

Third and fourth generation owners, Hiroshi and Kazuhiro Sakurai (Image Source: Forbes)

 

Another consequential change was who made Dassai Sake. Traditionally a Japanese brewery is run by a toji, a master brewer who leads a seasonal crew, carries the craft in his head, and governs each brew by experience and intuition. The toji were guild-trained specialists who came down from farming villages to brew through the winter and returned home in spring. Dassai's own toji system came to an end in 1999, when its ageing master brewer retired and the company chose not to replace him. Instead of hiring another toji, Dassai built a permanent, salaried, in-house brewing team, and never went back.

In an industry that often treats the toji as the soul of a brewery, running without one looked like heresy. But freeing itself from the toji turned out to be freeing for the company in the larger sense. The old system tied brewing to the cold months and to one man's fixed methods. A permanent team in temperature-controlled rooms could brew all year round, in every season, and could do something the seasonal calendar never allowed: run trial after trial, compare batch against batch, and improve continuously rather than waiting a full year to try again. Hiroshi Sakurai set that direction and proved it could work.

The company now, is run by his son, Kazuhiro Sakurai (who led our masterclass), the fourth generation, who joined the family firm in 2006. If the father's achievement was to decide that a tiny mountain brewery should make the biggest sake brand in Japan, the son's has been to decide that its stage is the whole world, and, as we will later see, possibly beyond it. The reinvention did not stop with the man who started it.

Buying a quarter of the nation's Yamada Nishiki rice

If the first rule at Dassai is to brew only the top grade, the second is just as unbending: brew it from one rice, and one rice only. That rice is Yamada Nishiki, widely called the king of sake rice. Over more than thirty years of brewing nothing else, Dassai has made itself, in its own description, a house of Yamada Nishiki specialists.

 

 

The reason Yamada Nishiki is highly sought after by daiginjo brewers lies at the centre of the grain. Each kernel of sake rice carries a shinpaku, an opaque, chalky-white starchy heart (the word means, roughly, 'white heart'). Under the husk and outer layers of the grain sit most of its proteins, fats and minerals; the clean, fermentable starch is concentrated in that central core. Those outer layers are what a heavy polish is meant to remove, because in the finished sake proteins and fats turn into the compounds that read as heavy, savoury or bitter, the earthy, slightly bran-like character. Reach the core and strip the rest away, and you are left with almost pure starch for the koji and yeast to work on.

Yamada Nishiki happens to carry an unusually large, well-defined shinpaku, and that is the technical reason it survives extreme milling. Its naturally low protein and fat content help too, which is most of what people mean when they call it the ideal rice for this kind of sake.

 

(Image Source: Japan Sake)

 

All of that makes Yamada Nishiki lovely to brew with, but a challenge to grow.

While modern table-rice varieties have been bred short and sturdy, Yamada Nishiki is a tall plant with large, heavy grains, and that combination makes it top-heavy and prone to lodging: the stalks bend and topple over in the field before harvest, especially in wind or heavy rain. Lodging is a rice farmer's nightmare. A flattened crop is harder to harvest, more likely to rot or grow mould where it touches wet ground, and it yields less usable grain. Yamada Nishiki therefore gives less grain per field than those everyday varieties. A farmer who grows it earns less per hectare and works harder for the privilege, which is why the acreage under it fell for years and why fewer growers wanted anything to do with it.

Which makes Dassai's headline number stunning. The brewery buys around 9,000 tonnes of Yamada Nishiki a year, from growers spread across roughly twenty prefectures. That is about a quarter of all the Yamada Nishiki grown in Japan! Sit with that for a second: a single brewery, up a valley in Yamaguchi, takes in something like one grain in every four of the country's premier sake rice.

Getting hold of that much of a difficult rice took a fight. The brewery realised that there wasn’t good enough rice at home, and that is precisely why Dassai had to learn to find good rice everywhere. When Hiroshi Sakurai went looking for good sake rice, he found that the local agricultural cooperative was reluctant to grow it. The brewery thus set about signing direct contracts for Yamada Nishiki with individual farmers instead. Those contracts now reach far past Yamaguchi, from Kumamoto in the south to Tochigi and Niigata in the north, into places once thought too cold for the crop.

 

The premium Dassai Beyond the Beyond 2022, made with rice grown from the winning entry of the competition (Image Source: Sotheby's)

 

Dassai today fiercely advocates for its favourite rice variety and tries to make it well worth a farmer's while by turning rice farming into a contest. Its 'Beyond the Best Yamada-Nishiki' project, launched in 2019, works like a competition: contracted growers submit their finest rice, and the single grand-prize lot is bought at roughly twenty-five times the going market price. The winning rice is then brewed into an ultra-limited sake, a bottle from one contest-winning batch has gone under the hammer at Sotheby's for a small fortune. Dassai treats its rice sourcing less as procurement than as research and development, the one raw material it is least willing to compromise on.

Grinding down to reach the pure core

The numbers you see on Dassai’s labels, 23, 39, 45, are organised around one measurement: how much of each grain of rice is left after milling. This is the polishing ratio, or seimai-buai. Dassai 45 keeps 45% of each grain, with 55% milled away. Dassai 39 keeps 39%. The flagship, Dassai 23, keeps just 23%, which means 77% of every grain has been ground off before a drop of sake is made. For comparison’s sake, the white rice most people cook and eat has only about a tenth of the grain removed; a basic ginjo has roughly 40% taken off; even a standard daiginjo need only reach the halfway mark. Polishing to 23% removes more than half as much grain as the law demands for the top grade, and it is slow, patient work, days of gentle abrasion kept cool enough that the grains neither crack nor scorch.

 

Dassai created an unprecedented 23% polishing ratio sake - the Dassai 23, that first grabbed the public's attention for the sheer labour and difficulty in achieving such a feat. (Image Source: Dassai)

  

By the brewery's account, when it first developed the Dassai 23, it took about 168 hours of polishing to reach that 23% rice polishing ratio for the first time. Some of this was motivated by pride. But the extra milling certainly changes what drinkers experience in the glass.

It could best be described as 'toumeikan', or 'translucency': bright, delicate top notes, a silky texture and a clean sweetness, with none of the grittier, heavier flavours of the rice bran. A well polished sake tastes comparatively airy and perfumed because impurities have been taken away. With that background noise gone, it lets the esters of fruit and flowers come forward.

 

 

We were poured a glass of the Dassai 23. The aroma had a fresh tartness to it, a faint lactic tang over something crisp and dry, closer to a light dry white wine: white grapes, white peach, lychee, honeydew, all bright and estery, with a cool floral edge. On the palate it was cleaner and crisper still, green melon and a soft dairy note somewhere between yogurt and cultured butter, lifted by jasmine, with the flesh of a white peach hiding just under the sweetness. There’s a long elegant softly honeyed finish.

Compared to its siblings 39 and 45, the Dassai 23 is the most elegant and the most sharply defined, its top notes gentle but precise, sweeter and yet cleaner than the 39, and noticeably crisper than the 45. Beneath those airy top notes there was still a flavourful sweet, faintly creamy body.

The koji room that never sleeps

It is worth going back, now, to the koji room mentioned at the start of this piece. We have already seen what it makes. But why can it never be switched off? Part of the answer is that koji is the most important thing a brewer makes. There is an old brewers' saying for it, ichi-koji, ni-moto, san-tsukuri, which ranks the three things that decide a sake in order of importance: first the koji, second the moto (the yeast starter, a small vigorous culture of yeast grown before the main tank), and third the tsukuri (the main fermentation itself). Koji is placed first because everything after it depends on getting it right. Get the koji wrong, and no amount of care later can put the sake right.

 

(Image Source: Dassai)

 

As the koji mould grows over the steamed rice, it feeds itself by giving off enzymes, biological scissors that cut large starch molecules into smaller sugar molecules. In a single tank, the koji keeps releasing sugar while the yeast, right beside it, is already turning that sugar into alcohol. Brewers call this multiple parallel fermentation. It is also why the koji has to be right. It is the engine that feeds everything else in the tank.

Growing it properly is slow, manual work. Dassai makes the koji for its top sake entirely by hand, without machinery, over about two and a half days, the same ancestral method used by Japanese breweries for centuries. Freshly steamed rice is cooled to the right warmth and carried into the koji room, a large temperature- and humidity-controlled chamber built to hold heat and humidity. The brewers dust the rice with tanekoji, the fine green koji spores, shaking them over the grain through a sieve. The seeded rice is heaped together and covered to keep it warm, and as the mould takes hold and starts to give off heat of its own, it is broken apart and spread out again, over and over, so the temperature stays even and the threads of mould run through every grain. Certain factors cannot be read off a dial. The brewers judge how a batch is doing by how it smells, how warm it feels, and how the grains clump and fall apart in the hand. 

Once a batch of koji is started, it has to be watched without a proper break, day and night, until it is ready about sixty hours later. The mould does not pause for a weekend. And because Dassai gave up the seasonal master-brewer system and now brews in temperature-controlled rooms in every month of the year, there is nearly always a batch of koji alive somewhere in the building. So four people take the koji in shifts, around the clock and through the holidays, at close to 40 degrees Celsius. That includes the first days of January, when almost the whole of Japan shuts down for oshogatsu, the New Year, the most important holiday in the calendar. In the twelve-storey brewery, three floors are given over to koji rooms, so that at almost any hour there is a bed of it somewhere overhead, warm and being watched.

Tema, and the refusal to automate

Despite all its scientific implements, Dassai keeps insisting that it is, at heart, a brewery made by hand. It has a word for the idea, tema (手間), and no tidy English translation. Tema means putting in the time, the effort and, above all, the human touch and care needed to make something beautiful. At Dassai, wherever a person’s hands and senses do a job better than a machine, a person does it.

 

Dassai employs several artisans who work alongside mechanised systems to create its sakes without the need of a toji. (Image Source: Dassai)

 

There are around 130 people in the production department, and another 80 or so handling everything around it, from shipping onward, which makes Dassai the largest sake-brewing team in Japan. Most breweries have spent the past few decades trying to make sake with fewer people, letting machines take the night shifts. Dassai went the other way and hired.

It is easiest to appreciate the need for these hands at the washing stage, before the rice is even steamed. Rice for sake is rinsed and then soaked so that it takes up water evenly, and for Dassai’s grade of sake that soak has to be judged to within a fraction of a percent of the grain’s weight. Get it wrong and the batch drifts from the start: rice that drinks in too much water turns soft and dissolves too fast in the tank, muddying the sake, while rice left too dry steams unevenly and resists the koji mould that has to grow into it. The rice makes this fussier than it sounds. So Dassai washes it in cold water, by hand, in small lots on the order of ten kilograms at a time, and times the soak closely, pulling the rice the moment it has taken up its target weight.

(Image Source: Dassai)

 

Add the hand-made koji you have already met, a few floors up, and you’d understand the labour that goes into the concept of tema. The instinct runs deep in the wider culture of Japanese making, where the artisan carries an almost moral charge, the sense that they owe the material their full attention. A machine cannot take in what a person notices through the five senses, so a person stays in the loop wherever that noticing counts.

Dassai’s meticulously tracked moromi

Which brings us back to the chart mentioned at the start. Dassai gave up its master brewer decades ago and, rather than hand the brewery to a new one, handed it to a team who steers each tank with great attention.

 

 

To briefly illustrate the amount of detail the team goes into, Kazuhiro put a single sheet of paper on the screen. It is a moromi control sheet. Moromi is the main fermentation mash, the tank where rice, koji, water and yeast all work at once: the koji’s enzymes keep freeing sugar from the rice while the yeast, in the same tank, keeps turning that sugar into alcohol. This sheet follows one tank of Dassai 23 from the first day to pressing, a column at a time. To a casual onlooker, it looks more like a hospital chart for a batch of sake.

 

Tucked in the header we can see that this batch was brewed by “A Team” (Aチーム). Beneath it sits the recipe, the enzymatic balance, the rice and water built up in stages, with about a fifth of all the rice in the tank given over to koji.

Top right sits the plan: a printed, fixed reference curve labelled the “true original-extract curve” for a 23 per cent recipe, which charts how the sweetness of a perfect Dassai 23 is expected climb and then ease off over about a month.

Underneath that runs a plot of how the batch actually behaved. The temperature climbs to a gentle peak and then coming down a long, deliberate slope, showing us the rate of fermentation which was held low and slow for the best part of a month which is probably what protects the delicate, honeyed aromatics Dassai 23 is bought for. The other line is the Baumé which stands in for how far along the fermentation has proceeded. It starts high, when the rice is dissolving and the mash is sweet, and slides towards zero as the yeast eats through that sugar.

Feeding both graphs is a dense grid of figures, one column for each day based on samples drawn from the tank with readings entered by hand. The work the team does every day to read the gap between the two graphs, the living tank against the fixed ideal, and decide whether the batch is running hot, sluggish or on schedule, then steer it back with the temperature or the timing of the next addition.

That is what took the master brewer’s place. Not a machine that brews on its own, but a team measuring a living thing closely enough to make better decisions about it by hand: a brewery that reads its sake like a chart so its people can keep their hands on it. The whole case, in the end, is one chart, one living tank held against an ideal reference.

The finest Dassai doesn't have a number

Almost every Dassai you have met so far wears its number on the label. Forty-five, thirty-nine, twenty-three: the figure on the label is the polishing ratio, and for years it doubled as the pitch, a promise of how far the rice had been milled towards its clean core. But one of the most expensive bottle of Dassai makes wears no number at all. It is called Dassai Beyond, in Japanese "Migaki Sono Saki e", roughly “polishing, and beyond”. By the time it appeared, several rival breweries had drawn level with Dassai at the top of the polishing race, matching or nearing the 23 per cent mark that had made its name.

 

 

Here is the twist. Recall that a sake earns the “daiginjo” grade by polishing off at least half of each grain, and “junmai daiginjo” if it does so with nothing but rice, water, koji and yeast. Both labels rest on a declared polishing ratio. Beyond declares none. Its milling rate is kept secret and shifts from batch to batch, and under Japanese labelling rules a sake that will not state its ratio cannot be called junmai daiginjo at all. So the single most refined bottle in the range is, on paper, the one Dassai is not allowed to label with the grade that other bottles carry. 

What it will not print on the label, it makes up for in the tank. Beyond starts with top grade Yamada Nishiki Dassai can buy, and is polished harder than anything else in the range, to an estimated 19 per cent (the brewery never confirms the figure as it prefers to let it drift with each harvest). The fermentation is supposedly run longer and colder still than the 23’s. And at the end Dassai keeps only the heart of the pressing. Sake leaves the mash in three phases, and the cleanest is the middle run, the nakadori; Beyond is drawn from that portion alone, which is part of why a single tank yields much less than what it otherwise might.

The pressing itself is also unique. Most breweries part the finished sake from the spent rice solids, the lees, by squeezing the mash in a press, often with weights. Dassai is the first brewery to spin the mash in a centrifuge, so the clear sake flies free of the solids under its own weight and nothing is forced – avoiding the coarser compounds. Dassai Beyond is the bottle built to show what that gentleness buys: a cleaner, silkier texture with the delicate aromatics left intact.

For all that, Dassai is insistent about what Beyond is not. In a statement signed by the president, the brewery insists that Beyond “is not a more perfected version of 23; it is built on 23 and made as a different sake altogether”. The aim is a complexity, a layering and a length of finish that a conventional junmai daiginjo cannot reach, not a tidier 23.

Beyond was more than ten years in the making and first appeared in 2012, sold at first only alongside a bottle of the 23. In Japan it now sits in fine-wine territory. Beyond also rides a wider turn in premium sake, a growing view that the polishing number has become a crude stand-in for quality and that the best sakes are better judged on what is in the glass than on the percentage on the label.

 

 

We had the opportunity to taste the Dassai Beyond. Where the 23 had been bright and sharply drawn, Beyond was quieter and more complete. The nose was exceptionally pure and polished: muscat grape, Japanese pear and delicate white flowers, with a faint sweetness of rice koji underneath that never turned grainy. The palate was silky, with a slight viscosity that gave it more weight than its easy drinkability first suggested, pear and muscat at the core, and a cool, firm mineral sensation building through the middle before the fruit opened out again.

Side by side, Beyond is broader, silkier and more structured than the 23, with a longer and more composed finish.

From a Yamaguchi valley to New York, and up to the Moon

For a brewery hidden up a mountain valley, Dassai’s ambition is stated with unusual bluntness: it is global, and it is large. We saw at the start that Dassai already sells in more than thirty countries. The company has said out loud where it wants to go next, to grow its sales five fold from around ¥19.5 billion to ¥100 billion. 

Kazuhiro Sakurai was candid that he initially did not really believe sake could travel until he visited New York himself. Once his conviction came, Dassai began pushing in earnest to put its sake in front of the rest of the world. 

 

A Dassai near you? Dassai's new US brewery in Hyde Park, New York. (Image Source: Dassai) 

 

The belief eventually took physical form. In September 2023 Dassai opened a full brewery not in Japan but in Hyde Park, New York, called Dassai Blue, so that it could brew on American soil rather than only ship there. The name carries the whole hope of the project. It comes from an old East Asian proverb, “from indigo comes a blue deeper than indigo” (青は藍より出でて藍より青し), used to express hope that a student could surpass the master. The wish written into the name is that Dassai brewed in New York might one day be better than Dassai brewed in Yamaguchi: the father’s house, outdone by its own offshoot abroad.

And then the discussion left the Earth. Kazuhiro took us through the Dassai Moon Project which was launched in recent years with the stated intention to build a brewery on the Moon, on the reasoning that when people eventually live on the lunar surface they will want good sake waiting for them. Rice, Dassai points out, is a better raw material than grapes for a journey like this for a practical reason: it is lighter to carry.

 

 

It sounds like a slide made to raise a smile, and then Kazuhiro showed that the first part has already happened. Working with Mitsubishi Heavy Industries and using Japan’s Kibo laboratory on the International Space Station, Dassai ran a fermentation in simulated lunar gravity, one-sixth of Earth’s, a real test of whether the biology of brewing works at all under Moon-like conditions. In one-sixth gravity the physics a brewer quietly relies on start to change: heat and carbon dioxide move differently through a tank when there is far less weight to drive convection and carry bubbles up, so there was no guarantee the yeast would behave as it does at home. The experiment was run aboard the ISS by the Japanese astronaut Kimiya Yui over about two weeks from late November 2025. This April 2026 Dassai and Mitsubishi announced that fermentation had been confirmed for the first time in human history under lunar-gravity conditions: the mash reached about 12 per cent alcohol, and a small returned portion was pressed at the home brewery into roughly 116 millilitres of sake.

The sake that came back, called Dassai Moon, Space Brewing, is being offered as a single 100 millilitre bottle made of titanium, priced at ¥110 million, more than US$700,000, with the proceeds going to Japan’s space development effort. 

 

 

A brewery that grew up in a remote valley has already made sake ferment in the gravity of the Moon, and has sealed a sake inside a bottle worth more than a house. The lunar brewery is still decades off. But the hard part, whether the living thing in the tank would work so far from home, has already been answered. The koji, it turns out, keeps no office hours even in space.

 

@CharsiuCharlie