Miso contains multitudes. “When I meet somebody from a different region [of Japan], we always start talking about what kinds of miso soup they make,” says Naoko Takei Moore, an LA-based cookbook author who also sells artisanal miso in her donabe store, Toiro. “It’s fun. You get to learn about where they’re from.”
“It depends on the climate,” says Ai Fujimoto of Omiso, a small-batch miso maker in LA known for its miso-dama, or ready-made miso soup balls, inspired by Southern California’s produce. “What you think is a ‘classic’ miso soup depends on where you come from. I’m originally from an area near Kyoto, and what my mom would make is probably very sweet for people from Tokyo.”
Because of its centuries-long history in Japan, miso has developed into distinct regional styles with diverse flavors and colors—from intense dark reddish brown in the coldest, northern prefectures, to mild and pale in the warmer south. And this isn’t exactly a continuous spectrum: Aichi prefecture, where Nagoya is located, is known for its almost black Hatcho miso, while nearby Kyoto prefecture is known for very light Saikyo miso.
The salty fermented paste dates so far back in Japanese cooking that even its origins are disputed—some cite evidence of early miso-like foods existing in Japan since the Iron Age (300 BCE–300 AD, give or take), while others think it came more recently from China, when Buddhist priests brought salted soybean paste to Japan during the Tang Dynasty (618–705 AD). Miso as we know it today traces back to at least the 900s, and probably to the 700s. Miso soup—eaten daily in traditional Japanese meals—became a samurai staple in the 12th century.
What is miso?
While miso has diversified since its earliest days, its basic methods haven’t changed a whole lot. It’s made by mixing cooked soybeans (although alternatives exist) with a grain (usually rice, but barley and soybeans are also traditional) that has been inoculated with Aspergillus oryzae mold a.k.a. koji—the same koji used in sake brewing—and adding salt and water, then leaving it to ferment.
Miso is a living food and, when allowed to ferment naturally, expresses terroir, a unique flavor profile influenced by the combination of ingredients, climate, and time. (More on this in a minute.) This can yield a gorgeous complexity of aroma and flavor—including a variety of umami, sweet, and floral notes—alongside its earthy saltiness. The characteristics of a given miso paste will be imparted to the dish you use it in.
Often, mass market miso rely on commercial koji and accelerated fermentation, along with flavor additives, so they can be more one-note (much like the difference between a low-intervention ‘natural’ wine versus mass-produced bottles). For quality miso, a good rule of thumb is to look for ingredient labels that list only water, soybeans, koji grain, and salt. Some labels will also list alcohol, which may be added for flavor or be a natural byproduct of fermentation. If there’s more than that listed, it’s probably not high quality. That said, while it’s worth seeking out miso without additives for the complex flavors and probiotic health benefits, a lot of grocery store miso does the job fine, especially if you plan to cook it for more than a minute (cooking for long periods kills the probiotics and removes some nuance anyway).
What to look (and taste!) for
If you’re new to miso, you may need to buy some that you don’t end up loving, at least at first, before you figure out your preferences. “Because there are so many kinds, and every person has a different taste, you have to choose what’s good for your palate,” Moore says. “You kind of have to give it a try.”
