A Guide to Osake (Japanese Rice Wine)
Well, this is embarrassing. I’ve spent the better part of the last five years building a career as a sommelier, studying wine as well as key satellite beverages like beer and sake. I thought I knew a lot. But this field of work has a funny, if not at times frustrating, way of reminding you that you still have a lot to learn. Like the other day when I discovered that in Japan, “sake” doesn’t actually refer to the fermented rice beverage, but rather all alcoholic drinks in general. There, it’s apparently known as “nihonshu,” or “Japanese alcohol.”
Clearly, it’s time for a sake refresher course. Here’s the 101 tour of Japan’s fascinating, iconic fermented beverage.
How It’s Made
Let’s knock out the big burning question first: Is sake more like wine (as is commonly assumed and treated) or like beer?
As with wine, the production season for sake begins in the fall, when the rice is harvested. However, the actual fermentation process, in which starch from a grain is converted from sugar to alcohol, is much more akin to how beer is made. So really, to call it “rice wine” is a misnomer, the beverage actually produced in a facility referred to as a brewery made by sake brewers. Still, I’d say all three are equally amazing for their ability to produce such an incredible variety of styles and types of products from just a few basic raw ingredients.
In the case of sake, those ingredients are: Rice, water, a type of mold spore called “koji,” and yeast.
First things first, about that rice. The rice used to make sake is a variety called “sakamai,” and unlike the kind that we’re used to consuming, it has a high pure starch content that is distinct from the grain’s protein and fat. There are some 70 to 80 different types of rice within this category used for brewing, each ultimately lending unique flavor components—light, full, floral, earthy, etc.—to the finished product.
Sakamai rice by Fukumitsuya Sake Brewery
While the type of rice is important of course, what arguably has a more significant effect on the final beverage is how the grain is processed, aka the polishing. The degree to which the grains are polished, removing the protein and fat to isolate the pure starch, is what ends up determining the style of the sake (more on that later). Generally speaking, though, the more the rice is polished, the higher quality the sake. It’s a supply and demand question that even my non-functioning econ brain can understand: Low yield and a higher quality, more labor-intensive product equals a more expensive, premium product.
Once the rice is polished the designated amount, it is then washed, soaked, and steamed, and the koji mold is induced. Now, please, don’t get all Squeamish Sally on me. Think of it in the same way you would a good, stinky blue cheese, this is a mold you want at the party. In fact, in order to make sake, you need it. Without it, the starch in the rice cannot be converted to sugar, which is essential to the fermentation process.
Koji mold on rice via VinePair
Next, a yeast starter is introduced to a small portion of rice (about a fifth of the batch), koji, and water, where it does what it does best: eats sugar and, um, “expels” alcohol. Gradually, increasing amounts of the ingredients are added to the tank, and after about two and a half weeks to a month, fermentation is complete. For more premium styles, the process is intentionally low (the starting temp is much cooler than for beer or wine) and slow, to help coax out more aromatics. With fermentation complete, the brewers then have the opportunity to make some stylistic decisions (including, for example, the addition of a percentage of distilled alcohol), after which the sake is matured in barrels for six months to a year.
Style Guide & Glossary
The kind of rice, the yeast, the quality of water, the decision to filter or not filter—it all contributes to the flavor and characteristics of the sake produced. But as mentioned before, the most significant determinant in style is the rice polishing ratio. For curious, teacher’s pet-type students in the room, the term for the milling ratio is “seimaibuai” and is expressed according to how much of the grain is left, not how much has been removed. I know, stick with me. So, for instance, if you’re told the sake has a seimaibuai of 70%, it means that 30% of the grain was polished off.
Also crucial in designating style is the decision of whether or not to add distilled alcohol to influence the flavor, aroma, and texture profile. Sakes produced without any additions to the rice-water-koji-yeast base are referred to as “Junmai,” aka “pure rice,” and you’ll either see the term on its own or affixed to another style-indicating name.
Okay so, let’s take a look at the six basic categories of sake:
Junmai: Pure, unadulterated sake. While most affirm that the grain needs to be polished to 70% to qualify, some claim that because of advances in technology, the ratio regulation for this style has been abolished. Taste-wise, Junmai tends to be on the richer, fuller bodied side, with bright acidity, and earthier notes. Because it has more body, these kinds of sake can stand up well to heartier foods.
Honjozo: Also polished to 70%, these sakes have a small amount of distilled alcohol added to them. They’re more on the light, mildly fragrant, easy-to-drink side. A good beginner’s choice that is not too assertive and won’t overpower food.
Ginjo & Junmai Ginjo: A more premium sake, both styles require that the rice be polished to 60%. Specific yeast and fermentation techniques result in a beverage that is light and complex, usually with intense, fragrant aromatics.
Dai Ginjo & Junmai Dai Ginjo: Clocking in at a minimum of 50% polished, this is, as they say, the really good stuff. The pricey, premium brew requires a lot of technical know-how and painstaking labor to produce—it’s the pride of the brewer, the ultimate reflection of their skill and ability. Generally, these will be very light, delicate, and complex with an elegant fragrant, fruity profile.
And as a bonus round, some additional helpful style terms:
Nigori: Aka unfiltered sake (actually, technically, it’s coarsely filtered but the effect is there). The liquid in these will appear noticeably cloudy, with fine particles of yeast and the rice polishings left in. It usually has a more rice-forward flavor, with a slightly sweet, creamy quality and a thick, rounder (if not at times piecey) texture.
Nigori sake by Luigi Anzivino
Nama-zake: While most sakes are pasteurized twice, those labeled with this term have not been at all. They must be kept cold and fall on the fresh and fruity, sweet aromatics side of the spectrum.
Koshu: This aged style of sake requires that the liquid sit in barrel for at least three years, taking on a darker, more amber color and caramelized, sweet-savory flavors and aromas similar to a sherry or madeira.
Koshu sake by Japan Travel
Shiboritate: Think of this as the Beaujolais Nouveau of sake; instead of spending the usual time in barrel post-fermentation, this fresh-press style of sake hits the market ASAP and is marked by a wild, fruity flavor.
Hot n’ Cold
As with wine, serving temperature can either enhance or detract from the drinking experience. While nothing’s written in stone, it’s generally agreed that lighter, fruitier styles like ginjo and dai ginjo are best served cold, which helps highlight their delicate flavors and aromatics, while richer, earthier styles are better warm or at room temperature. Junmai and honjozo, meanwhile, are more versatile and can be served either way.
Just be mindful of not taking it to the extreme in either direction, too cool, and the sake’s profile will be completely dulled. Overheating can be dangerous too, it’s best to slowly and gently warm up a carafe of sake in a water bath. When in doubt, you can always ask the shop or server what they recommend, and don’t discount your personal preference. If you prefer your sake at a particular temperature, go for it.
Approach tasting sake as you would tasting wine (hopefully not by dropping a shotglass full into a pint of beer and chugging it). If you’re going to be studious about it, you’ll want to evaluate appearance (Is it clear or cloudy?), aroma (Fruity? Floral? Earthy?), taste (Does it follow what you smelled? Is it different? Are any new flavors introduced?), texture (Smooth? Light? Rich? Piecey?), and aftertaste.
As such, many recommend forgoing the iconic small ceramic cups (which are actually better for warm sake) in favor of regular wine glasses which make it easier to appreciate its diverse characteristics. And for the high-quality dai ginjo stuff, some even suggest opting for Burgundy style wine glasses with larger bowls to help enhance the appreciation of aromatics.
Most importantly though, try not take it all too seriously. Have fun discovering and tasting products of this incredible, delicious craft.