It is finally beginning to get cold, which must bring a collective sigh of relief from sake brewers all over the country. The unseasonably warm temperatures of late are not good for brewing sake. Since just about now is when brewers dig in and begin to brew their best stuff, not enough cold could spoil the party.
As the brewers labor away in the cold, perhaps you are kicking back with a glass of sake. Maybe it is even a sake recommended in this column. If so, you may have noticed the listing of a few “vital statistics” listed along with the description.
Among those would have been the seimai-buai. What does that number actually refer to, and what significance does it have? How does it affect the final flavor of the sake?
The seimai-buai is the degree to which the rice used in brewing has been milled, and is expressed as a percentage. For example, white table rice starts, of course, as brown rice, and is milled so that about 8 percent of the outside of each grain is ground away. This means that the grains are about 92 percent of their original size.
This rice is said (in the sake-brewing industry anyway) to have a seimai-buai of 92 percent. The number expresses what remains, not what was ground away; if the outer 20 percent has been milled away, the rice would have a seimai-buai of 80 percent.
Sake rice is often milled much further, especially in the production of premium sake. In fact, a specified minimum seimai-buai is part of the definition of the several grades of premium sake. Honjozo and junmai-shu must be brewed with rice with a minimum seimai-buai of 70 percent, i.e., the outer 30 percent has been ground away. Ginjo-shu calls for a seimai-buai of at least 60 percent, while daiginjo requires a 50 percent seimai-buai.
This number is often listed on the label of a bottle, especially in the case of fine sake. Often, for good daiginjo, this number can be as low as 35 percent, meaning 65 percent has been ground into powder and removed before even beginning to brew.
But why? What is accomplished by all this seeming wastefulness? In the end, better sake, of course.
Sake rice (which is different from table rice) usually has the fermentable starches concentrated in a little packet in the center of the kernel. In the outer part of the kernel are fats, proteins and other nasties that contribute to off-flavors and can inhibit fermentation. By polishing (an industry-wide euphemism for milling) the rice, these less-desirable components are eliminated from the equation.
As a general statement with plenty of exceptions, more polishing leads to better sake, or at least lighter, more refined sake. Note, too, that this whole thing can be taken too far: Too much polishing can lead to sake devoid of character and a bit too ethereal.
It is also not really feasible to say that you should look for a sake with a seimai-buai of 40 percent or better (as an example). It is merely one number that indicates a little about a given sake, and placing undue importance on it should be avoided.
The nuka, the white powder ground off of the rice, is not wasted. It is fermented by large sake brewers for use in cheap sake; it is also used in the production of wagashi (Japanese sweets).
In brewing, rice polishing is not a trivial step. A sake-world adage says: Ichi: koji, ni: moto, san: tsukuri. Loosely rendered as “first the koji, then the moto (yeast starter), then the main mash,” it indicates the importance of creating good koji, the mold-covered rice that breaks starches to sugars for fermentation.
The quality of the koji depends on how the rice has been steamed. It should be much firmer than table rice, harder on the outside but soft on the inside. Some say the condition of the rice then determines everything.
The steaming step, again, is dependent on the water content of the rice before steaming, and the consistent distribution of that water content within the rice kernels. This is fine-tuned before steaming to within a 1- or 2-percent range.
The ability, or lack thereof, of the rice to absorb water is in turn determined by the polishing. As the rice is milled, the friction generates heat that makes the rice harder and less absorbent. In premium sake, steps are taken to minimize this.
Not all breweries own one, but modern seimaiki (rice-polishing machines) are computer-controlled contraptions that allow control of various factors; how much will be polished away, and in how much time, are two of the most important. The more slowly the rice is polished, the less heat is generated, and the rice can be adjusted to the correct water content more easily. This affects the steaming, which affects the koji, and everything on down the line to the final product.
As mentioned previously, the seimai-buai is often (but not always) readily available information, either printed on the back label or listed in books, magazines and on menus. One can begin to develop expectations for what a sake may be like based on this information.
For more information about sake and to sign up for a free sake-related e-mail newsletter see www.sake-world.com. To be put on a contact list for information on sake-related tours, events and seminars, e-mail firstname.lastname@example.org or fax name and address to (03) 3460-8233.
Suwaizumi (Tottori Prefecture)
“Mantensei” junmai ginjo-shu
Seimai-buai: 55 percent
Tottori is a real “sleeper” of a prefecture when it comes to sake. It hardly pops into one’s mind when considering well-known sake regions, but among the relatively small number of breweries there, a lot of sterling sake is brewed.
This junmai ginjo has a soft, honey-laced nose with just a tad of fruitiness hovering in the background. The impact on the palate is steady and calm, but with richness and overall balance in a slightly dry profile.
If you can find it and don’t mind paying a bit more, Suwaizumi makes a daiginjo called Otori that is in demand all over the country.
In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.