Sake is brewed — and not distilled — from rice. The alcohol content is initially about 20 percent, but this is usually watered down to about 16 percent, which is just a tad more than most wine. But sake is closer to beer than wine, at least in terms of how it is made.
Sake is brewed from a grain just as beer is, and the processes have some similarities. Both barley (beer) and rice (sake) contain only starches, not the sugars that are to be converted by the yeast cells into carbon dioxide and alcohol. In beer, this starch-to-sugar conversion takes place with the help of malting the barley, a step in which enzymes are created. In sake, the husk-less rice cannot be malted, so the enzymes are contributed with the help of a mold known as koji-kin.
One thing that makes sake brewing different from beer brewing (and unique in all the world) is that this starch-to-sugar conversion and the conversion of that sugar to alcohol and carbon dioxide take place simultaneously, in the same tank, and not sequentially as in barley-based beverages.
A quick overview of sake brewing might look like this: Rice is milled, then steamed. Some of it is inoculated with the enzyme-producing koji-kin. Next, a small vat of this is mixed with more rice and water, and yeast is added. For two weeks or so, the yeast propagates until there are about 2 million yeast cells in a teaspoon of the liquid. To this, more rice, moldy rice (koji) and water are added over four days to create a large tank of white mash. This then sits and ferments for 18 to 36 days. After this, the clear sake is pressed away from what remains of the rice. It is then allowed to mature for a while, and may be filtered and pasteurized.
The difference between good sake and bad sake depends on several things. One is the water. Sake is about 80 percent water, and most kura (breweries) were built over or near good sources of water. Although it can be doctored and filtered, starting with good water is essential.
Next, of course, is the rice. Sake rice is different from the rice we eat at the table in several ways. It is larger, and has more starch and less protein and fat, which adversely affect fermentation and final flavor. Also, in the best sake rice, the crucial starches are conveniently located in the very center of the rice grains, allowing the fats and proteins to be milled away, leaving only the goodies behind. Great sake rice leads to great sake, but it can easily cost three times as much as regular rice.
The more the rice is milled, the more fats and proteins are removed, and the cleaner and more elegant the final sake will be.
After the rice and water, there are the craftsmen who brew the sake. The skill of the people guiding the sake through its journey from rice to potential ambrosia is just as important as the raw materials themselves. Their ability — based on experience, honed senses and intuition to make the countless minute adjustments that are called for on a day-to-day basis — will determine much about the flavor profile.
A drinking hierarchy
About 80 percent of all the sake produced in Japan is run-of-the-mill “table” sake. While some of this can be perfectly drinkable, it does not qualify for special grade designation.
The main grade classifications are listed below. While the definitions themselves center on how much the rice has been milled, much more labor-intensive, automation-eschewing, stress-inducing methods are used at these levels to create the fragrant, refined styles they represent.
Honjozo ( ): Rice has been milled to remove at least the outer 30 percent, and a very small amount of distilled alcohol has been added to lighten the flavor and improve the fragrance. Light and easy to drink.
Junmaishu ( ): Rice has been milled to remove at least the outer 30 percent, and nothing but rice is used in brewing; i.e., no alcohol added. More sturdy in flavor, often with a bolstering acidity.
Ginjoshu ( ): Rice has been milled to remove at least the outer 40 percent, and a very small amount of distilled alcohol has been added to lighten the flavor and improve the fragrance. Delicate and elegant, often fragrant.
Junmai ginjoshu ( ): Rice has been milled to remove at least the outer 40 percent, and nothing but rice is used in brewing. Very similar to straight ginjo-shu, sometimes slightly fuller.
Daiginjoshu ( ): Rice has been milled to remove at least the outer 50 percent, and a very small amount of distilled alcohol has been added to lighten the flavor and improve the fragrance. Even more refined and graceful; can be quite fragrant.
Junmai daiginjoshu ( ): Rice has been milled to remove at least the outer 50 percent, and nothing but rice is used in brewing. Quite refined, elegant and generally fragrant.
Perhaps the most important thing to keep in mind about the above classifications is that there is massive overlap between the grades, and in the end these classifications serve only as very general indicators. Your palate will tell you all you need to know.
While some experimental aging does take place, in general sake is consumed within a year of being released from the brewery. While there are good years and bad years for rice, just as there are for grapes, good brewers can make up for a bad year with a bit more effort.
The goal is consistency of flavor from year to year. As such, there is no vintage system for sake. Like wine, it is vulnerable to oxygen and so should be consumed soon after opening the bottle.
And what of sake-drinking etiquette? The only thing remotely resembling a rule is that you don’t pour sake for yourself. You pour for your drinking partners who, in turn, return the favor. But even this breaks down as the evening wears on.