“I massage the rice throughout the night, every few hours. I worry about it.” Ken Hirata speaks with a hushed passion, a certain intimacy about his ingredients—rice, kōji, sweet potatoes, patience. Patience is one of the most important ingredients of authentic Japanese imo (sweet potato) shōchū. And persistence.
These are qualities the revered Master Toshihiro Manzen must have sensed that night at the izakaya (tavern) over sips of shōchū, when the Japanese surfer shared his dream of building a traditional shōchū distillery in the Hawaiian Islands. The master had previously turned down Ken’s appeals for an apprenticeship—five times. (Ken wasn’t family, as succession usually went.) But that night, the master was intrigued by the earnest seeker or maybe by the promise of introducing America to ancient imo shōchū handcrafting. He agreed to a three-year tutelage, and Ken was on his way to translating a centuries-old art for a New World palate.
“Many people think we drink sake all the time,” says Ken. “But in Japan, we drink more shōchū.”
The distilled spirit, indeed, started outselling sake in Japan over a decade ago. But that was only after its image experienced a renaissance. Once thought of as a low-brow alcohol favored by the working class, shōchū was rediscovered in Japan by a new generation. Shōchū was suddenly hip. So hip that sweet potatoes in the famed imo shōchū–making region of Kagoshima became scarce, unable to keep up with demand. Although shōchū can be made from other sources—barley, sugarcane, rice—drinkers of imo shōchū, in particular, love its robust, earthy depth with a cultlike devotion.
Over 4,000 miles away from Kagoshima, where Ken spent his apprenticeship, he and his wife, Yumiko, began building their small distillery on Oahu’s North Shore. They had to moonlight at first to make ends meet, picking plumeria flowers for lei makers’ fragrant strands. But now, less than five years later, they’re selling out of the 6,000 annual bottles they produce, only months after each season’s release. To the Hiratas, they’re simply living their dream in a little beach town called Haleiwa—known for its big waves, laid-back lifestyle, and now American-made sweet-potato spirits.
It starts with the kōji. This miraculous mold also inspires fermentation in such ingredients as miso, shoyu, and mirin. In other words, it needs a medium to grow in, which leads to kōji rice. Ken’s preferred rice is an heirloom variety he sources from a Japanese American family farm in California. The kōji he imports directly from Japan at the start of each new batch. Sometimes the kōji is black, sometimes white—each type lends a distinct taste to the steamed rice it grows into, which the Hiratas stack in neat towers of wooden trays in a climate-controlled room.
In those first few days of production, Ken is consumed with concern. It could be the midnight rice massages, as he helps distribute the kōji mold among the grains. Or the perfection of temperature and humidity necessary in the kōji room. Maybe it’s the silent, suggested presence of Master Manzen, whose ceramic kametsubo (fermentation vats), more than 100 years old, dot the floor of the Hiratas’ pristine distillery.
Planted nearly three feet in the earth to maintain the coolness of their contents, these massive vats are key to an unbroken tradition. This is where a slurry of kōji rice, yeast, and water begins its fruity weeklong fermentation. The sweet potatoes chosen for each shōchū batch—whether a single variety or in combination, usually Okinawan or Molokai purple, often fuchsia or orange in color—are steamed, mashed, then added to the kametsubo. After another 10 or so days, the bubbling concoction goes into the Hiratas’ kidaru (traditional cypress wood still), where it will transform into a liquor of ultimately 30 percent alcohol.
How a clear, unfiltered liquid results from a vibrant-hued mash seems incongruous, but, really, it’s chemistry—distillation turns anything clear. Once the mixture is heated in the wooden still, its steam rises through the pipes then passes into a condensing tank, where it travels down through a coiled pipe ensconced in cooling water and, finally, drips pure magic into a holding tank to mature.
What happens to the leftover mash?
In Kagoshima, they feed it to their livestock. Ken gives his leftovers to the sweet potato–growing neighbors whose crops he often blends with his own. The farmers feed the spent mash back into their fields as compost, to encourage more delicious sweet potatoes for the next shōchū run.
For authentic, or honkaku, shōchū, Ken distills only once, while some companies in Japan have mass-production equipment that allows for many distillations of the same batch. But the mechanized process doesn’t use kōji, Ken notes, and multiple distillations lead to spirits that taste less like their ingredients. The Hiratas’ attentive approach, like that of Master Manzen and other traditional distillers in Japan, where every hard-earned step is done by hand, is more physically demanding.
“This is analog,” Ken says.
Steaming, fermenting, distilling—the Hiratas perform a dozen or more rounds of this process, using a remarkable 15,000 to 20,000 pounds of sweet potatoes, until the holding tank is finally full. In four more months, the shōchū is mature and the season’s single batch is born.
As with a vintner’s wine, each batch is subtly different from the last. It depends on the sweet potatoes and the kōji, the rain, the sun, and trade winds, the nuanced hands-on techniques that tell Ken just when the kōji rice is ready, when the fermentation of the sweet potatoes is complete. One year, the Hiratas made a Three Islands shōchū, named for the North Shore, Big Island, and Molokai sweet potatoes used. Last season’s batch was nicknamed Backyard Blend, referring to the potatoes pulled from their own six acres.
Getting to Namihana
Late September marks the release of Namihana shōchū batch #9, the first Hawaiian Shochu Company blend to feature Kauai-only sweet potatoes. A few weeks later, the production of batch #10 will kick into gear and continue through November. Haleiwa is about 25 miles north of Honolulu International Airport (HNL), so you’ll need a car to get to the distillery. For a shōchū tasting and distillery tour, contact Ken Hirata directly at firstname.lastname@example.org.