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Newsletter Archive 2007

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Sake World Newsletter


July 2007



Yeast, Yamahai, and Rafters

Yeast, Yamahai, and Rafters
Many times during presentations on sake yeast types and their effects on the flavors and aromas, the question has arisen: Do any brewers still use wild yeast? In other words, do all brewers add cultured yeast to their yeast starters? And, with great confidence, I have always answered, "There are no brewers using naturally occurring yeasts from the environment any more; there is too much at risk, and too much to be gained by using cultured yeast strains that will give very specific and predictable results." But, as so often happens, I have discovered an exception to the rule. It is the way of the sake world. (For a review of the most commonly used yeast types today, click here.)

Indeed, until about 100 years ago, most sake was brewed by allowing the yeast strains resident in the brewery to drop in to the yeast starter tank and take off. Of course, when brewers had a particularly good batch, some would take the foam and reconstitute the yeast for re-use. But still, very often what made or broke a brewery was their "yane-tsuki-kobo," or the "yeast cells sticking to the rafters." Some had good ones, others did not.

Then, at the beginning of the 20th century, they began to isolate and eventually distribute pure strains of yeast, after which no one really bothered to use the ambient ones. Why bother, when you can be so much more safe, and on top of that, choose from a range of yeast types that will ostensibly yield predictable results.

And, indeed, I was sure no one did at all anymore, until I stumbled upon the sake of Furousen in Shiga Prefecture (just north of Kyoto) at a recent tasting. While I had tasted their sake before, this was the first time to do so with a "data sheet" at hand, in which the rice, milling, alcohol, SMV (i.e. nihonshu-do), acidity, amino acid content (like I need that...), and yeast type were all listed. For the yeast for all their sake, it simply said "mutenka," or "none added (i.e. naturally occurring yeast)." Now this got my attention.

So I struck up a conversation with the company rep, the young owner-inherit, who was both knowledgeable and proud of what they are doing.

"So, you mean, you don't add *any* yeast, to *any* of your batches? It's all naturally occurring, stuff that is floating around there in the kura?" This seemed all too risky and unnecessary in these modern times, at least to me.

"Yup, you got it," he asserted, smiling the whole time. He seemed to give off the vibe that this was the most natural thing in the world. (Which actually it was, until about 100 years ago.)   

"Wow. That's wild, man. I was sure *no one* was doing that anymore. What gives? Are you guys the only ones doing this? Are there are others? Have you always done it this way? If not, how long? How do you (technically) pull that off?" A had a gazillion questions...

He took it all in stride. Obviously, he was used to them, and seemed to thrive in this situation as well. He patiently, smilingly, explained that yes, to his knowledge, Furousen was the only kura in the country that made all of their sake with naturally occurring yeast anymore. "Oh, there's a couple of places I hear-tell are doing a tank or two that way, but no one is as committed to the process - or as insane - as we are." While obviously these were not his exact words, his original Japanese did not stray too far from this tongue-in-cheek, self-depreciating yet confidently knowing tone.

He further explained that they had been dabbling with it for a good long time, but that it had been about a decade or so since everything they made came to be done this way. "It's not such a big deal, really," he explained matter-of-factly, massively downplaying the issue. "It's just the way our toji feels it should be done, just what he thinks is the best way for our way of brewing.

I still wanted to know how they did it. Sake is an open-to-the-world fermentation. How did they manage to ensure they got all the right stuff, and none of the bad?

"Aw, it's gotta be yamahai, man, there's no two ways about it..." Yamahai. Of course.

He was referring, of course, to that older, traditional way of preparing the yeast starter, yamahai-shikomi, often shunned because of the attendant idiosyncrasies of flavor, but also the added hassles and time involved in making such sake. As many readers surely remember well, yamahai yeast starters take about a month, twice the normal amount of time, and are prepared in a way that allows natural lactic bacteria to create the lactic acid that cleans out the environment before yeast is put in - or falls in, as is the case here. Most sake out there has this lactic acid added in pure store-bought form, which does the job more quickly and cleanly.

But if one is going to let natural yeast cells do their thing, apparently, it has got to be yamahai. And this is the miracle of this old, traditional method: the rise and fall of the the natural micro-organisms involved conspire in such a way that only yeast types appropriate for sake brewing make it through the chemical gauntlet of the yamahai yeast starter to the fermentation stage. Bear in mind that this was not deliberately designed this way 1000 years ago, it developed in this way through trial, error and tweaking.

But still, I persisted, how can you ensure yeast strains that will yield good sake, your house style, or even something predictable?

"Remember," he began, "that we brew a lot of sake in the same place, and have been for a long time. From each batch, there are tons of yeast cells going out on walkabout from the rising swaths of foam up into the air, and sticking on to the rafters and what have you. Sure, there are other kinds of yeast here, but the overwhelming population is what we want it to be, and are counting on it to be."

So they start by mixing rice, water, and koji (that enzyme-rich moldy rice that converts the starches to sugar), and controlling the temperature very tightly. "Just one degree (C) difference at this stage, and we will end up with a different sake," he says.

After about 20 days, the porridge-like mash will begin to bubble. "If it starts to bubble before that, then it's 'haya-waki,' ('early bubbling'), and you know you got the wrong strain of yeast in there." From there, if sanitation and temperature are maintained, it will be ready for use in another week to ten days, providing enough yeast to power the month-long fermentation to follow.

Running through the sake they had at the booth, I was impressed. With all that wildness running around, I expected rougher stuff. The kura is known for its array of, um, curious products. But this was not the case. 

The half-dozen or so I happily tasted were decidedly and surprisingly not some of those "whack ya upside the head with a two-by-four" yamahai types. Yamahai can be bolstering in its acidity, sweetness, and wild gaminess - but it doesn't have to be. And some producers choose to push that envelope, aiming for an extreme style that can unfortunately represent quintessential yamahai to some consumers. Sometimes, it can give yamahai a bad name.

Rather, these all displayed a vibrant vestige of subtlety and grace. They were deep in flavor, and long-finishing, with sweetness, cinnamon, and smokiness running throughout.

If nothing else, this all serves to reassure that in spite of all the hullabaloo about modern methods and technology, with the umpteen choices of cultured yeast types that brewers have at their disposal, that long ago, folks were indeed drinking good sake using naturally occurring, drop-in-the-tank yeasts, thank you very much. And while no other kura make take it to the extremes that Furousen does, at least one exception to the rule exists in them.

For the record, Furousen does not currently export. In fact, their production is quite small. Also, much more on yamahai can be found in the archives of this newsletter, at

Sake Events and Announcements

Unlike last month, not much is up in July, as summer is a quiet time in the industry, and not much is happening until the fall.

New York City, August 27, 28, and 29, 2007

On August 27, 28 and 29, I will hold the first stateside version of the Sake Professional Course in New York City at the Jolly Hotel Madison at 38th and Madison. The content of this three-day intensive sake course will be identical to that of the Sake Professional Course held each January in Japan, excepting of course the sake brewery visits and evening meals.
The course is geared toward industry professionals wishing to expand their horizons in a thorough manner into the world of sake, and will therefore necessarily be fairly technical in nature, and admittedly somewhat intense. But the course is open to anyone with an interest in sake, and it will certainly be fun! The course lectures and tastings will begin with the utter basics and will thoroughly progress through and cover everything related to sake. There will be an emphasis on empirical experience, with plenty of exposure to a wide range of sake in the tasting sessions throughout the three days.
Each day will provide the environment for a focused, intense and concerted training period, and will consist of classroom sessions on all things sake-related, followed by relevant tasting sessions.
The goal of this course is that no sake stone will be left unturned. Every conceivable sake-related topic will be covered, and each lecture will be complimented and supplanted by a relevant tasting. Participants won't simply hear about rice type differences and yeast type differences, they will taste them. Students will not only absorb technical data about yamahai, kimoto, nama genshu, aged sake and region-related difference, they will absorb the pertinent flavors and aromas within the related sake as well.
Like its counterpart held in Japan each winter, it will be quite simply the most thorough English-language sake education in existence.
The cost for the three-day class, including all materials and all sake for tasting, is US$750. Participation is limited, and reservations can be made now to secure a seat, with a deposit of half the above amount being due July 15. For a view of the syllabus, please see For reservations or inquiries, please send an email to SakeCourseStateside(at mark)
Event management and PR for the above course are being handled by Hanna Lee Communications.

Questions and comments should be directed to John Gauntner. Email John from this link:

All material Copyright, John Gauntner & Sake World Inc.
1-4-4 Jomyoji, Kamakura-shi, Kanagawa-ken, Japan, 243-0003


Copyright 1999

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