"The first written record of shochu was actually graffiti on a temple," Rule of Thirds partner George Padilla told me. "In the 1500s, some builders working on a temple had scrawled, in the wood, a snide comment about the high priest being stingy with his shochu. Fittingly, this is the first record of what is, still today, considered a blue-collar beverage in Japan."

Japan's oldest, most traditional alcoholic beverage, shochu, is a clear, distilled spirit made from fermented, well, almost anything. "I've actually calculated this once," Kyushu-based orthopedic researcher by day; The Complete Guide to Japanese Drinks author, Cool Japan Honkaku Shochu Ambassador, Sake School of America instructor, Japanese Sake & Shochu Makers Association consultant, and cofounder of Kanpai blog by night Stephen Lyman shared with me. "For all the different decisions made during the process, there are literally millions of styles of shochu you can make. The scope is enormous."

How is shochu made?

As The Shochu Handbook author, Sake on Air podcast host, and fellow Cool Japan Honkaku Shochu Ambassador Christopher Pellegrini put it, "Shochu is not about what it's made from, but how it's made." While gin must be made with juniper, rum from a sugar base, and brandy from a fruit, honkaku ("authentic") shochu can be made from 54 different ingredients, of which there are 200 approved variants.

Most commonly, shochu is made from a mash of sweet potato, barley, rice, brown sugar, buckwheat, or sake lees (the koji-inoculated mash leftover from sake production). But, there also exist honkaku shochu made with mugwort, chestnut, enoki mushroom, onion, green tea, wakame seaweed, shiso, and sesame. (It's important to note that these are ingredients, not flavorings — the only ingredient that can be legally added to honkaku shochu is water, for dilution.)

Shochu's creamy mouthfeel and complex flavor is due to the parallel fermentation processes (sound familiar?) that occur in the still: There's saccharification (the base ingredient's starches convert to sugar) via black, white, or yellow koji (remember koji?), and alcoholic fermentation (yeasts consume sugar to produce alcohol). The former is called "first moromi," the latter "second moromi."

After about two weeks, the moromi is then vacuum-distilled (depressurized and boiled at a low-ish temperature) or atmospheric-distilled (boiled at a high temperature). Vacuum distillation is typically reserved for lighter, floral, and aromatic barley- or rice-based shochu, so as to preserve the more delicate notes of banana, melon, and star anise. Atmospheric distillation results in a more robustly-flavored spirit, teasing out mushroom-y, earthy, yeasty notes from sweet potato shochu.

While honkaku shochu is only distilled once, ko-rui shochu, the cheapest alcohol available in Japan, is distilled continuously to yield pure ethanol and, Lyman assures me, is not drunk for its taste. Korui-shochu is, effectively, the same as Korean soju (sharing the same etymological root that means "burned alcohol"), but the latter will often have citric acid and flavorings added post-distillation.

Wait, so what is it?

If shochu is a spirit that has limitless creative potential, that captures the essence of a specific time and place, that is produced in three times the quantity of tequila in Mexico — why isn't it more widely known?

"I think people see a Japanese clear spirit that's not full-strength, and they get confused," Padilla said. "If it's not sake, then what is it?"

Shochu authority and Mizu Shochu co-founder Jesse Falowitz echoed Padilla's hypothesis. "In the '80s and '90s, the baby boomers in Japan were really enamored with sake and its origins as an 'everyman alcohol.' It certainly was not as elevated as it is now — what with the polishing of rice and push behind marketing. The shochu industry hasn't had the know-how, or quite honestly, the motivation to market overseas." But that's starting to change.

Falowitz continued: "People are accustomed to drinking spirits that are 10 to 20 percent higher A.B.V. than shochu is typically sold at. So many bartenders have expressed to me that they've wanted to work with shochu, but just couldn't because the lower proof was hard to work with in a cocktail. So, we started working with this distillery that's over 100 years old on a genshu, or undiluted, shochu."

Many brands had tried, and failed, to market shochu as a lower-proof spirit. Falowitz is encouraged by Mizu's success as a higher-proof spirit — at the standard 35 percent A.B.V., it's sold alongside vodka and gin — and says competitors like Iichiko are taking note and pivoting similarly.

How to buy and drink shochu

To get an idea of how a shochu will taste, first see what it's made from.

"Rice-based shochu share some of the notes found in sake. They're light, fruity, tropical, and softer on the nose," Padilla explained. "A barley-based shochu will be rich, toasty, and nutty. And shochu made from sweet potato — my personal favorite — is deeply aromatic, with an umami fruit to it. They're definitely the more strange, challenging ones of the bunch."

Or, do as I usually do when selecting a wine, and look for an eye-catching bottle or label. No, really, Lyman agrees: "If you can't read kanji, and sometimes, producers don't even put this information on the label either — you can tell whether a shochu has been vacuum- or atmospheric-distilled by the color of glass or label."

While not a hard and fast rule, "generally, a white or light bottle will be vacuum-distilled, and so, will taste lighter; a dark bottle suggests atmospheric-distillation and resultantly, an earthier, more robust shochu," Lyman said. (If you're not super keen on shochu roulette, Lyman and Pellegrini have over 80 detailed shochu reviews on Kanpai.)

Iichiko is one of the most widely distributed, well-known shochu brands out there," said Padilla. "They were responsible for making shochu hip again in the '90s in Tokyo. But, one of the first ones I ever tried was Beni Otome, which has a totally uncommon base ingredient — sesame — and tastes just like black sesame ice cream. It makes a great introductory shochu. I like it on the rocks; it works well as an aperitif or after-dinner drink."

For one that's especially versatile, Padillas recommends a sweet-potato-based shochu (like this one from Manzen Shuzo). "While I usually drink it with ice or diluted with cold water (mizuwari) in equal parts, I'll also sometimes drink it after dinner with hot water (oyuwari) — it's really soothing. This week, since it's going to be so hot, if I were to have people over and have shochu to start the hang, I'd serve a chilled shochu diluted seven parts water to three shochu, for a refreshing, light-bodied drink that's almost like water, but just enough alcohol to take the edge off."

Mizu's three expressions — barley, lemongrass, and green tea — each clock in at 35 percent A.B.V., lending themselves especially well to mixed drinks. Falowitz explained that the barley one, made with black koji, tastes like a "hybrid between a young whisky and sake. The nose is sake-like — tropical, banana, cantaloupe — but it drinks like vanilla custard, pear, green apple, and ripe banana."

The green tea variant, also made with black koji and saga barley, gets freshly picked and steamed green tea leaves added to the mash, yielding a shochu rich with umami, chocolate, and dried seaweed notes. I was surprised to find that the lemongrass — made from rice, white koji, and organic, mountain-grown lemongrass harvested by retired Japanese rice farmers (you can't make this stuff up) — did indeed taste like a hybrid between gin and sake, as Falowitz said it would. Herbaceous and citrusy, but creamy like an amazake.

When I asked Falowitz if there's anything he wishes could be debunked concerning the already deeply misunderstood spirit, he told me: "A few years ago, the equivalent of The Today Show in Japan interviewed the oldest guy in Japan, who's something like 120 years old. They asked for his secret, and you know what he said? A glass of shochu a day."

This story was originally published on Food52.com: A Beginner's Guide to Shochu