All You Ever Wanted To Know About Sake Yeasts

The topic of yeast in sake brewing is huge these days. Over the last ten years or so, dozens of new yeast strains have been developed and come into use. This has been one of those great technical advances in the sake world - one factor that separates great ginjo of today from the run-of-the-mill sake of yesteryear.

It is interesting and important to note that yeast development is one area of progress that has taken place outside of the actual brewing process, yet still affects the final product greatly. In other words, great sake might be brewed using a brand-spankin' new yeast strain, but the actual brewing process be old, hand-made ways that eschew modern machinery.

How important is yeast? Quite. The selection of the yeast in brewing sake affects many things. Most noticeably, fragrance. But, since our sense of taste is highly affected by - if not dependent on - our sense of smell, this is important.

Properly tasting sake includes several phases of gainfully employing the sense of smell. There is the initial sniff, noting the general fragrance of a sake. There is also the fukumi-ka, which is a fragrance that arises as you hold the sake in your mouth and breathe. There is also the modori-ka, a third fragrance that becomes discernible immediately after you expel or swallow a sip. Yeast will affect all of these.

More on the chemical side, yeast - as most people well know - converts sugar to alcohol and carbon dioxide. It is the heart of the creation of all alcoholic beverages. But different yeast strains will produce different things, like esters, alcohols, and acids and other chemical compounds that affect the nuances of fragrance and flavor.

Each yeast will give rise to its array of chemical compounds, with scary names like ethyl n-caproate and isamyl acetate. These will be present in varying quantities, depending on the choice of yeast and the successful progress (or lack thereof) of the fermentation. Which esters, alcohols and other compounds are produced are highly dependent on the temperature at which fermentation takes place. All of this will help to determine the character and nature of the sake. In this way, the choice of yeast also directly affects flavor.

How does one strain of yeast physically differ from another? There are many ways, but not all are so obvious. It is often not simply a matter of size or physical appearance. In fact, when the cells of two yeast strains are set next to each other in a microscope, the average person is not likely to be able to tell the difference.

The differences are more evident in other things. Like the length of the life cycle of the yeast: how long will it work before becoming dormant, or how robust or fickle it is against alcohol and/or temperature. Which alcohols, esters and other things it tends to give off as by-products of its life cycle during fermentation is of course, another important factor.

New Yeast Development

Although we speak of a yeast being "developed," it is more a matter of being isolated. The process of coming up with a new, specialized yeast strain usually takes about three years, and is actually a kind of reverse engineering.

Yeast is usually isolated by starting with a tank of sake being made. It may be one in which many, many strains of naturally occurring (i.e. floating in the air) yeast strains were allowed to initiate the fermentation. Some of the thick foam on the top of the moromi (the fermenting mash) is taken and analyzed. This foam has the highest concentration of yeast cells in the tank. If the sake comes out well, the strain of yeast that is most populous is isolated and reproduced for further study. If it continues to demonstrate the desired qualities, it is made available on a larger scale.

This first took place in the early 1900's. The Central Brewers' Union would take pure yeast strains that had been isolated (usually by larger breweries from particularly good tanks of sake) and make them available to kura across the nation in pure form, usually in small glass vials.

These yeast strains were assigned numbers by the Central Brewers' Union. At present, they are up to number 15. Each one has its own special qualities. Yeast #1 through #6 are no longer in use, as apparently the acid produced was too strong.

Yeast #7, #9, and #10 are perhaps the most important these days. Yeast #7, discovered by Masumi of Nagano, is the single most commonly used yeast in the country, with its mellow fragrance and robust strength during fermentation. Yeast #9 is the most common yeast for ginjo-shu, due to its wonderful fragrance-creating abilities, and fairly healthy constitution during fermentation. Yeast #10 produces a lower-acid, fine-grained flavor in sake, but is a bit fickle at all but the lowest fermentation temperatures.

More recently, Yeast #14 - low in acidity with lots of pears and apples in the fragrance - and Yeast #15 - very fragrant but not of such robust constitution, are often seen used in finer sake, especially in particular regions.

There are, on top of the publicly available yeast strains, dozens of others that are used on varying scales throughout Japan. Many of these are proprietary, having been developed by kura and used only by them, or more commonly, developed by prefectural brewing research institutes and used by kura in that prefecture.

Many of these are wonderful indeed, and go well with the water and rice of that region. A few examples of this include F701, also known as Utsukushima Yume Kobo from Fukushima, the wonderfully fragrant Alps Kobo from Nagano, and HD-1 and NEW-5, which help Shizuoka sake be the wonderfully drinkable brew that it is.

And finally, no discussion of sake yeast would be complete without mention of the awa-nashi kobo, or foamless yeasts. Yeast #6, #7, #9 and #10 all have cousins that do almost an identical job without producing the massive amounts of foam that rise and fall and breathe majestically throughout the course of the fermentation. These are designated by adding a -01 to the number. For example, #901 is a foamless version of #9.

Why foamless? This saves hours and hours of grueling cleaning time, scraping the remnants of the foam from the side of a tank before starting the next batch. Also, since a third of each tank must usually be reserved for the rising foam, more sake can be brewed with less space using such awa-nashi yeast.

However, some experts say that the these foamless versions are not quite what their bubblin' cousins are, in terms of the final product. Fragrance and flavors are not quite as refined, although they may be 99 percent of the way there, say some. This is somewhat unsubstantiated, and may be nonsense. It is most likely affected by preconceived notions, but such talk has been heard.

Often these yeasts will be given working names, names that are more romantic than a simple number. One example given above is the F701 from Fukushima, known much more commonly as the Utsukushima Yume (dream) Kobo. Others include mighty #9, also known as Kumamoto Kobo, in honor of the prefecture from which it originally comes (more specifically, from the kura that brews the fragrant and very fruity sake Koro. Number 10 was discovered by a gent named Chikara Ogawa, so that it is often called Ogawa Kobo (especially in northern Japan, where it was isolated). Number 14 is often referred to as Kanazawa Kobo, and #15 is commonly known as AK-1, for Akita Kobo, both in recognition of their origins.

Yeast is one of the newer developments in the sake world that we can all follow with interest. Although it may not make much of a difference once you are sipping, learning to identify the qualities of a yeast strain and searching for and comparing fragrance and flavor profiles can be extremely instrumental in improving your palate. It can also simply be a lot of fun.

More and more commonly, especially for decent sake, the yeast used is listed on the bottle. Be sure to look for and try to identify the various special qualities of the various yeast strains.

Those with more interest in sake yeast will soon find an in-detail chart listing the various qualities of the various yeast strains, with other supplemental information, on my web page.

Sake to look for

Below are listed a few sake to look for. Along with a brief description of each is given a ranking on a 100 point scale, and any known information about whether it is available in the US.

Ranking sake is something I do grudgingly. It does little more than express how I feel personally about a sake. It is really up to each individual to determine for themselves how "good" or "not good" a sake is. I have based it on an arbitrary (but reasonable) 100-point system.

The Sake:

1. Yorokobi no Izumi, "Kyokuchi" Daiginjo, Okayama

The "Kyokuchi" sake comes in two varieties; one made with Yamada Nishiki rice, and one made with Omachi rice. They are different enough to be considered two entirely different sake. The one referred to here is the Yamada Nishika version.

Floral and honey facets to the settled but omni-present nose. Overall, light in flavor, but with an astoundingly well-structured flavor beneath that; solid, clean and subtly rich.

Rating: 91

2. Yoakemae, "Ki-ippon" Junmai-shu, Nagano

Lively, pro-active fragrance that jumps out to meet you, slightly rice-laced but with fruit essences like plum and fig hidden in there as well. Good, thick-boned flavor, soft and demure and slightly sweet. Wonderful slightly chilled on warm evenings.

Yoakemae also makes a wonderful nama (unpasteurized) version of this sake, rich and festive.

Rating: 87

3. Yaegaki, "Mu" Junmai-ginjo-shu, Hyogo

A wonderfully settled and calm sake. A faint, well rounded nose with pear notes and a bit of peach, perhaps a bit of greenery in their as well. Fundamentally a dry sake, but there is a smooth and refined rice-like flavor on top, that is robust and full. Fairly low acid presence, which allows the flavor to maintain its center-heavy richness. Available in the US for sure.

Rating: 83

4. Wakatsuru, Ki-Ippon, Toyama

A solidly-built sake but with a soft touch at the beginning. Slight apples and cantaloupe are seemingly apparent in the beginning, but fade quickly as the flavor becomes drier and firmer. Clean, with few off-flavors, but enough mouth feel to never bore. Slightly grainy tail will have its fans and foes. Should be available in the US already.

Rating: 83

5. Tsuki no Katsura, Junmai-ginjo-shu, Kyoto

Soft in a typically Kyoto-sake way. The sweeter facets bounce around with acidic tones to create a nice balance, delivered in a well-rounded package.

Tsuki no Katsura also makes a junmai nigori sake, that rich, cloudy pina colada of the sake world. Worth a try, although it can hardly be labeled subtle. Available in the US.

Rating: 84

6. Tenzan, "Hotaru-gawa" Junmai Ginjo-shu, Saga

A relatively fat, full flavor that hangs out a bit. A fairly low acidity keeps the flavors from running around in your mouth too much, lending a richness that stops just short of being cloying. Faint peaches in the nose fade into a drier than expected flavor that strikes the palate softly, with a buttery essence rising up later. Good at room temperature or slightly chilled. Be open, however, to experimentation. Soon to be available in the US.

Rating: 88

7. Tentaka, "Kokoro" Junmai Ginjo-shu

A clean and crisp sake, with a flavor that, while not really all that dry, is very solidly constructed. The moderate fragrance is touched with a bit of greenery, but slightly flowery on top of that. The acid content is fairly high but it gets buried (in a good way) within the other encompassing aspects of the flavor profile. Soon to be available in the US.

Rating: 89

8. Tatsuriki, "Akitsu" Junmai Daiginjo-shu, Hyogo

This sake is made entirely from the top-rated sake rice, Yamada Nishiki. Bitter tones and somewhat vegetation-laced elements play off of each other. The acidity hovers in the background, as an effective contrast, enlivening the other flavors. Mellow and settled, the almost intuitive richness comes out of the background. A bit of decanting-like exposure to air does this sake good. Best at room temperature or chilled.

Rating: 93

9. Sekai no Hana, Junmai-shu, Shimane

Slightly on the sweet side, without the higher acidity expected from a junmai-shu. It does, however, exhibit a typical Shimane touch in the nut-like essence in the nose, laced with faint, faint figs and prunes. Good at room temperature, but will present a more simple face when chilled.

Rating: 83

Where to Drink Good Sake in ... San Francisco

A recent trip to San Francisco presented the chance to check out firsthand a few places to buy and drink decent sake.

First of all, it seems best to do your shopping in Japantown. For better or for worse, most of the better sake is still being consumed by native Japanese living in the US. For that reason, it is best to shop where they shop.

In Japantown, or more specifically, on Post just beyond the Japan Center, is a small Japanese grocery called Maruwa. Down the street about 200 meters, on the opposite side of the street is found a similar store called Uoki. (Uoki, however, does not have its name in English out front.) Therein lie a source of perhaps 60 different sake.

Maruwa keeps its stock near the back of the store. They carry quite a wide range of domestic sake. Take note of the explanation of sake types in English on the wall by yours truly (which I was surprised to see).

Uoki has a similar but slightly better selection (although that is surely a matter of preference). Less of an emphasis on domestic sake, which simply means a harder-to-find or rarer overall selection. Most noteworthy here are Umenoyado Junmai Ginjo and Kubota “Hekiju,” the first for $34 and full but delicate, the second $78 and prized for its ultra light and clean flavor (yawn, say some).

Dinner time? Great. Head down to Blowfish Sushi to Die For, 2170 Bryant Street, but only after making reservations at 415-285-FUGU.

Although the focus of this review should be the sake, the food may end up stealing the show. As might the ambience. The place is a heluva lot of fun. Modern not-so-Japanese appetizers, with great presentation and lively flavors Naturally, usual suspects like sashimi are also available.

Beyond this is the expected array of sushi, a la carte, and a whole range of funky maki-zushi, hand-rolled sushi with great California-style stuffings. Top these off with one of about a half dozen desserts that are, well, to die for.

Ah yes, the sake. Plenty of that here too. There are ten to fifteen varieties in what seems to be a fairly stable menu. These include Masumi, Otokoyama, Onikoroshi, Harushika and others. They are generally available in single-serving and double-serving glasses. It would be great if they were to bolster this menu, and provide a bit more information (like prefecture) on each sake. But that's nit-picking.

Blowfish Sushi To Die For is located at 2170 Bryant (South of Market). Reservations are highly, highly recommended, especially for anything remotely resembling a large party. 415-285-3848

Sake Events

Finally, something for the all-too-neglected Kansai readers.

On the evening of Friday, November 12, at the Kobe Club in Kobe, there will be an evening of sake and pottery that is open to the public.

Myself and Japan Times Ceramics Scene columnist Rob Yellin will each give a presentation in our respective fields, followed by a wonderful five-course meal with an accompanying sake for each course. There will also be a short sake tasting before the meal for more thorough direct comparison.

Those interested should contact the Kobe Club directly at 078-241-2588 to make reservations. They can also be reached by email at kobeclub@gol.com. Participation is limited and the event is expected to fill up fast.

On the evening of Wednesday, October 27th, at the Japan Society in New York City, there will be a presentation on sake, followed by a sake tasting.

John Gauntner and Yasutaka Daimon, president of the brewery producing wonderful Rikyubai sake in Osaka, will speak on sake-brewing as a craft and art, and in particular about the toji head brewers, the craftsmen who direct the brewing of sake at kura (breweries) in Japan: their lives, their skills, and the culture that suffuses them. Call the Japan Society at 212-832-1155.

On the evening of Thursday, October 28th, and again on Friday, October 29th, there will be sampling of the sake premium sake during the dinner hours at Oyster Bar. Sake will be available for purchase with meals as well. Not to be missed. For more information as the days draw near, contact the Oyster Bar at 212-490-6650.

New Sake Book!!!

Be sure to check out the latest sake book on the market, Sake Pure & Simple, written by myself and the CEO of SakeOne Corporation, Grif Frost. The book is published by Stonebridge Press of Berkeley, and is available through Amazon, at bookstores like Kinokuniya, and for free by sending your name and address to SakeOne Corporation. (Send your mailing address to:

grif-frost@sakeone.com for a free copy of the sake book. Offer good for Sakeworld subscribers only and limited to one book per subscriber. Offer expires October 30.)

Sake Pure & Simple is colorful, with a design that is eye-catching and stimulating. It is in general a light-hearted but extremely informative read, with all you need or would want to know about sake, plus a bit.

Included is an excellent directory of where to buy sake and drink sake in cities all over North America.

Reader Feedback

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