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Koji - All You Wanted to Know (Part 2)

# 11

July 2000

Sake World Sake e-Newsletter

Issue #11

July 25, 2000


All you ever wanted to know about koji, Part 2
Of Rice and Region, Part 2
Sake World Newsletter archives posted!
Sake to look for
Sake-related events
Subscribe/unsubscribe information
Publication information
Koji Part II

Last month, we looked at just what koji and koji-kin are, what the function of koji is, and touched a bit upon its history. We saw that koji is steamed rice that has had the Aspergillus Oryzae mold (called koji-kin) propagated on to it, and that this converts starches in the rice into fermentable sugars for the yeast with the aid of enzymes produced as the mold works is way into the rice. Those that missed that article can refer to the archives at 

This month, we will look at the constantly challenging process by which koji is produced inside the brewery.

Koji is introduced to the sake-in-progress a total of four times. It goes into the initial mix, the yeast starter, and is subsequently added to the tank three times after that along with more regular steamed rice and water. As it takes about 42 to 50 hours to create a batch of koji, which must be then pitched into the fermentation tank, timing is of the essence.

Like most aspects of the sake-brewing process, koji making can now be automated to varying degrees. The simplest of these automated processes might be temperature sensors stuck into the mounds of koji-in-progress, whereas the other extreme is completely automated koji-making machines that mix constantly and maintain strict temperature control.

Each brewery seems to have its own tenets and beliefs about this. There are huge breweries (although admittedly few) that doggedly produce all their koji by hand, smaller breweries that crank almost all of it out by machine, and everything in between. Everyone has their own reasons, convictions and methods. Most insist that hand-made koji is the best and use this for their top grade sake, automating the process for lower grades. But some argue for machines, citing the incredible savings in labor and an increase in control.

Leaving the argument to the experts, let' look at the handmade process, as it is much more interesting of an explanation than that of the operation of a machine.

Immediately after rice has been steamed, that portion of it earmarked for koji production is cooled to just above room temperature. Sometimes this cooling is done by a conveyor-belt equipped machine, right out of the steaming vat. The tiny spores are sprinkled daintily over this cooled rice, with a certain number of grams of the mold used per kilogram of rice. The dark green spores come floating down like a barely visible smoke, so fine are they. Although the way it is sprinkled looks haphazard and nonchalant, it is a carefully measured process.

These koji-kin spores are sprinkled just before  or just after the batch has been taken to a special room in the sake brewery, called the koji muro, which is kept at a higher temperature (30C or so) and humidity. It is usually a low-ceilinged room with wooden walls and thick doors. Here, the koji-kin spores are thoroughly mixed into the warm rice by hand with a kneading motion, with usually several if not all of the brewers participating in this step, called tokomomi. The batch is then wrapped up in a large cloth to keep it warm and moist, and allowed to sit for several hours. It is then unwrapped, the clumps broken up and mixed thoroughly to evenly distribute temperature and moisture in a step called kirikaeshi.

Several hours later, when the developing koji has become visible in the form of a white frosting on the rice grains, it is divided up into wooden shallow trays about the size of a small desk drawer called koji-buta. There are various sizes of these trays, however, and usually only the best sake is produced using the smaller ones. Lesser grade sake might use small boxes perhaps ten times larger (or more) than the small koji-buta. But again, we are looking at the more labor intensive koji-making methods here. Within the koji muro, then, sit several high stacks of these individual koji-buta for any given batch of sake.

The koji gives off heat as the mold propagates, and to keep the temperature and humidity even the koji piles in the individual trays are mixed up, and their positions in the stacks rotated. For the best sake, the poor schmuck of a brilliant craftsman that is in charge of this seminal process gets up every two hours around the clock to mix and rotate the trays.

After a total of forty to fifty hours, the koji is ready to be used, and is usually removed from the koji muro and into a colder environment (just about anywhere in the brewery is colder than the muro) to put a halt to the propagation of the mold, putting it in a limbo of sorts. At this point, it looks like dry, frosting-laced grains. The taste is a bit sweet and the smell is a tad chestnut-like. The next day, it will be added to the already-fermenting tank with straight steamed rice and water.

Although the above is a gross simplification bordering on insulting to the craft, it is about all one needs to know to appreciate the role of koji in sake brewing. Should you get a chance to visit a sake brewery during brewing season, they may or may not let you into the koji-muro. Many kura are reluctant to risk contamination, especially for large, bumbling groups of tourist-like visitors. But if you go in a group of only a couple people, and especially if you have a connection, it should be easy to check the process out in person.

Koji production is the heart of sake brewing. It determines so much about the general path down which the fermentation will tread. Sake is unique in all the world in how koji fits into and drives the process. Not bad for a mold.

Of Rice and Region, Part II

Last month, we looked at what factors historically contributed to regional differences in the flavor profiles of sake from around the various regions of Japan. This month, we will look at a few of the major sake-brewing regions, and their representative characteristics.

The two most largest brewing regions in Japan are the Nada district of Kobe city in Hyogo prefecture, and the Fushimi district of Kyoto city in Kyoto Prefecture. In a sense, these two are the yin and yang of sake, as their styles are different but complementary. All of the largest dozen or so brewers are located in one of these two regions, yet both Nada and Fushimi have dozens of tiny brewers as well. They are both historically interesting and important.

The Nada district of Kobe, Hyogo Prefecture

Approximately one-third of all sake produced in Japan comes from this short strip of land near the port of Kobe. It is easily the most historically significant place on earth when it comes to sake. More advanced brewing technology, sake lore and history and fine brew has come from Nada and the rest of Hyogo Prefecture than any other locale.

Several factors worked together to make Hyogo in general, and Nada in particular, the undisputed sake center that it is. Perhaps the best sake rice in the country, a varietal known as Yamada Nishiki, grows wonderfully (if not best) here. Beyond that, in the mid-nineteenth century, water that flows down from Mr. Rokko and gets filtered beneath the ground was empirically determined to be perfect for making wonderful sake. Dubbed Miyamizu, or Shrine Water, it attracted countless sake brewers to the area.

A third factor contributing to Nada and the rest of Kobe' story history and success as a sake producing region was the fact that it lies along the sea. The access to a port made the shipping of sake to Edo (the old name for Tokyo) logistically easy. The demands of the thirsty and hedonistic upper class of Edo helped drive the expansion of the industry back in Nada in the nineteenth century.

Subsequently, countless companies set up shop to brew here. Many of these grew up to be the brewing giants that dominate the industry today. In fact nine of the top thirteen largest breweries in the country are located in the Nada district of Hyogo. Yet there are, of course, plenty of tiny kura as well. There are about 130 kura in Hyogo Prefecture, with 50 or so of them concentrated in the township of Nada.

Sake breweries in this region have gone through several decimations, including bombing during the war. Most recently was the Great Hanshin Earthquake of 1995, in which perhaps ten percent of the breweries (all smaller places) were put out of business.

Hyogo sake is, actually, a bit hard to describe. Generally the fragrance is demure and self-effacing rather than prominent. The flavor is settled and full, with lots of subtleties. It is definitely not a flowery of fruity style, as a rule. The hard water of the region lends a crispness and solidity to the flavor. Often Kobe sake is referred to as danseiteki, or masculine.

The Fushimi Ward of Kyoto (Kyoto Prefecture)

Less than an hour by train from Kobe lies Kyoto, the ancient capital of Japan. The Fushimi region within Kyoto city is, in many ways, a complement to the Nada region of Hyogo. Together they firmly establish the Kansai region (western Japan) as the predominant sake-brewing region in the country. More than half of Kyoto' 70-odd kura are located in Fushimi.

As a lot of sake was brewed in Kyoto for the Imperial court and its nobles, a market and environment that demanded the best developed. Near the end of the thirteenth century there were as many as 300 breweries in Kyoto. Competition fostered progress. Many significant technical developments, such as the isolation of koji spores and the use of a yeast starter, took place in Kyoto around that time.

Still, Kyoto did not begin producing sake on a large scale until the late 1800', and could not compete with Nada in the Edo market due to the lack of a seaport. But the development of a rail system changed all that, and Kyoto soon became No. 2 in production, and things remain that way today. In fact, Kyoto makes 13 percent of the nation' sake. The largest brewer in Japan, Gekkeikan, is in Kyoto, as are two more in the top seven. (Gekkeikan dauntingly dwarfs all other brewers in the world with its massive production.) However, interestingly enough, the region has its share of smaller kura as well: Kyoto does not have another kura in the top 50, in terms of production volume.

Kyoto sake is soft, spreading well across your palate and melting in quietly. It is often described as rather feminine sake, especially when directly compared with Nada sake, brewed with harder water. Kyoto sake has very delicate undercurrents that are often intuitively sensed rather than overtly tasted. Rich yet unpretentious, good Kyoto sake can render you speechless with its nobility and grace.

Next month, we will look at a few more significant brewing regions, in particular Niigata, made famous years ago during the *jizake boom.*

Sake World email Newsletter Archives Posted!

Finally, after almost a year of hot air and empty promises, all of the past issues of this newsletter have been posted in their entirety on the Sake World website. Just go to, click on the Sake Newsletter tab, click on Archived Email Versions, and select the issues you want to read from the chart. For those that have only recently signed up, now all the past issues can be downloaded and perused at your leisure.

All issues follow the same format, with a couple articles on sake-related lore, and several reviewed sake, followed by a (now moot) listing of sake-related event. Enjoy them.

Sake to Look For

Kokushi Muso

*Ichiya Shizuku* Daiginjo (Hokkaido)

Takasago Shuzo, brewers of Kokushi Muso, are located in Asahikawa, just about in the middle of the north island of Hokkaido. The winters are bitterly cold; just peachy for sake brewing. The brewery builds an igloo each year outside the brewery and dubs it The Ice Dome. Although it is basically a gimmick, this daiginjo is fermented and pressed inside this igloo.

The name Ichiya Shizuku means dripping through the night, which is how the sake is pressed. The moromi (fermenting mash) is, when ready, poured into meter-long canvas bags and tied off to allow the sake to drip out, with no pressure other than gravity weighing down on the sake. This method is referred to as Shizuku.

Gimmicks aside, Ichiya Shizuku is a fine, crisp, bone dry and wonderfully clean sake, with a mild fragrance and a delicate construction. It is a bit hard to find and a bit expensive at 4280 yen for a 720ml bottle, but worth a try if you are a fan of dry, crisp sake. The name Kokushi Muso is worth remembering as their other products are also tasty, in particular their Tokubetsu Junmai-shu.


Junmai Ginjo (Kochi Prefecture)

This brewery, located in a prefecture known for its drinkers, has been around since 1869, and has long brewed under the meigara (brand name) of Tama-no-i. This past year, they added a second label to their product list, that of Minami. They are very, very tiny, brewing only 50 to 60 kiloliters, all of it premium sake.

Minami is dry and moderately fragrant, with a flowery-herb laced essence to the nose. Like much Kochi sake, it is light but not without content; a pleasant evasive richness lurks behind the dry profile. Way too easy to drink way too much of this sake.

Minami has developed quite a devoted following in Tokyo. It is one of a bunch of new faces to appear among the ranks of popular sake in certain sake pubs and at certain retailers. I like to refer to this group of seeming newcomers as the Brat Pack of premium sake. Hiroki, introduced last month, is another member of this venerable Brat Pack.


Junmai Ginjo (Akita Prefecture)

Akita, near the northern tip of the main island of Honshu, is the fourth largest sake-brewing prefecture in Japan. This brewery was originally founded in 1865, and was at first a small family owned brewery. They have grown considerably over the years, and now brew from two separate breweries, the second under the name of Kariho. The soft water used in brewing runs down from the nearby mountains, gushing up in a nearby spring, giving their sake a soft and gentle overall feel.

Dewatsuru produces a wide range of sake, and their strength  is in their consistency. Their sake is reliable and tasty. This particular junmai ginjo is fairly dry and crisp, with a gentle nose, and an excellent balance between the various flavors and fragrances. The flavor is lively and expressive, with a subtle and intuitive richness.


*Tokusen* Honjozo (Hyogo Prefecture)

Hakushika is one of the ten largest brewers in Japan, and is located in Nada, the sake-brewing center of the Universe. It is too easy to just write off large brewers such as Hakushika as having fairly bland, cheap sake that is undeserving of our critical attention. But such a prejudice serves us not, and Hakushika is an excellent reminder of this.

Hakushika is pleasantly dry, but with a light and pleasing multi-faceted backdrop to its quiet front. Only mildly fragrant, there is a remarkable absence of off-flavors, with a smooth taste throughout. It is also widely available, in Japan and the US as well (although the products available may differ from place to place). A great sake for trying both gently warmed and slightly chilled.


Junmai Daiginjo, Honjozo, and other grades (Miyagi Prefecture)

I have an unreasonable attachment to this sake. Sure, it is popular, but my fondness for it borders on the peculiar. I have recommended the junmai daiginjo here, but really any Suminoe product is wonderfully drinkable. The honjozo is much more relaxed and less ostentatious, and that alone will satisfy. But the junmai daiginjo and their other premium products (they have several unpasteurized and unfiltered sake as well) will be more complex and fragrant.

Perhaps the most helpful and revealing thing to be said about this sake (and it is nothing more than a reflection of my personal preferences) is that it is incredibly intuitive. The complex, delicate and layered flavor is not so much overtly tasted as it is intuitively perceived. About three seconds after you taste it, just as your mind is about to move on to something else, you think Wow! Is that nice!

Although Suminoe is a very small brewery, you can find it at many good sake pubs, like Sasagin in Yoyogi Uehara, and larger retailers, like Koyama Shoten in Hachioji. Unfortunately, at present it is not available in the US.

Sake-related events

Japan Times Ceramics Scene writer and Japanese pottery expert Robert Yellin and I will be doing a joint seminar on sake and pottery on the evening of Saturday, September 2, at the sake pub Mushu in Awajicho, near Shin Ochanomizu/Awajicho Stations, from 6pm to 9pm. The evening will include a meal, half a dozen or so good sake, and lectures by Rob and I. Seating is limited and fills up fast.

To make a reservation, please email me or fax me at


Sake critic extraordinaire Haruo Matsuzaki will be holding a sake seminar on Saturday, August 26, from 6:30 until the last train at Romantei in Akebono-bashi (Yotsuya Yanagicho). Although this seminar will be entirely in Japanese, Matsuzaki-san' smarts and tasting ability are amazing and entertaining. Guaranteed fun. Seminars feature a short lecture with tasting, and an optional but highly recommended konshinkai (party) with food afterwards downstairs. Those interested can make a reservation through me at

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Sake World is distributed free via email only with the intent of disseminating useful information about sake and the culture and world that surrounds it. Information on sake, sake production, sake shops and sake pubs, sake events and sake culture are included, targeting audiences both in and out of Japan.

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Copyright 2000 Sake World



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