Dashi: The Ultimate Flavor Boost

Dashi, a broth made with seaweed and shavings from a hunk of dried fish, lends intense flavor to everything it touches—from classic Japanese food to some of America's most ambitious restaurant dishes. Writer Daniel Duane tries to re-create the umami-rich elixir at home.


The word dashi, until quite recently, held for me a linguistic status not unlike credit-default swaps back when the economy first imploded. I knew that dashi was a Japanese broth, and I knew that many of the smartest chefs in America—Wylie Dufresne, Eric Ripert, Jean-Georges Vongerichten and more—made dashi central to their cooking. And I’d heard that more and more chefs were following their example. But I had no real clue what dashi was. This became intolerable after I experienced the ethereal tofu mousseline with mushroom dashi at Daniel Patterson’s Coi in San Francisco, and the ecstasy of David Chang’s clams and potatoes with bacon dashi at Momofuku Noodle Bar in Manhattan. Self-respect now demanded that I make sense of this mysterious ingredient. For me, that meant not only learning how to make dashi, but also how to turbocharge other dishes with dashi’s savory power.

I began with a friend’s copy of an out-of-print 2009 book titled Dashi and Umami, with forewords by Heston Blumenthal and Nobu Matsuhisa. Dashi, I read, is the all-purpose stock and seasoning of traditional Japanese cooking, used in everything from fish-poaching liquids to salad dressings and typically composed of only two ingredients: kombu seaweed and dried, fermented bonito, a tuna-like fish. Kombu and dried bonito are both extremely high in flavor compounds known as glutamates, experienced by our palates as umami, the so-called fifth flavor. Glutamates exist in plenty of Western foods, like roast meats, dried anchovies, tomatoes, smoked pork and mushrooms. But dashi is critical to Japanese cooking in the way that olive oil is essential to Mediterranean food, making Japanese cuisine arguably the only one on earth built around not a cooking fat, but a flavor principle.

From Shizuo Tsuji’s 1980 ultra-classic, Japanese Cooking: A Simple Art, I discovered there are three levels of dashi: low-quality instant, made from a powdered mix; a more respectable version, made by steeping inexpensive kombu in hot water, along with bonito flakes sold in plastic bags (hana-katsuo); and finally, the high-end artisanal type, made with rare, expensive kombu and dried bonito purchased in whole, rock-hard fillets known as katsuo-bushi and shaved into flakes right before cooking. This last kind of dashi creates a profoundly transcendent broth of, in Tsuji’s words, “subtle flavor and delicate fragrance.”

Character being destiny, I decided to start my cooking experiment with the most ambitious dashi. For this, I needed to buy some katsuo-bushi. In San Francisco’s Japantown, Nijiya Market had about a dozen different kombus and fish-flake varieties, not to mention about 50 kinds of miso and whole rooms full of ramen noodles, but I couldn’t find a single employee who had ever even seen whole katsuo-bushi.

At Berkeley’s first-rate Tokyo Fish Market, I found a still-more-dizzying array of kombus and fish flakes, but no katsuo-bushi. A fishmonger, thrilled by my query, thought that US Customs bureaucrats had forbidden the importation of katsuo-bushi—much as they once embargoed Spanish jamón ibérico and raw French cheeses, tsk-tsking the food-safety practices of thousand-year-old, world-class gastronomic traditions.

My next thought was to try making the katsuo-bushi myself. Flipping through Dashi and Umami again, I read that I would first have to boil and debone bonito fillets, which I could certainly handle. The next step, smoking those fillets for six hours, sounded tolerable—I’d been meaning to buy a smoker anyway. Then I learned that I would have to smoke the fillets 15 times over the course of a month, scraping off built-up tar each time. And then I would have to sun-dry the fillets for several days, spray them with mold culture and leave them indoors for two more weeks to ferment. If I hadn’t yet killed myself in frustration, I would then have to scrape and sun-dry them again, and then maybe a few more times over the next two full years, until my wife’s attorney served divorce papers granting me sole custody of the fillets that, as my only consolation, would finally look and feel very much like wood.

I would not be doing that. So I decided to reach out to the only Japanese-influenced chef I knew personally, David Kinch, owner of the Michelin two-star Manresa in Los Gatos, California. I soon found myself in Kinch’s kitchen, trading a wad of cash for an oblong hunk of dried, smoked and fermented fish. Kinch remained vague about how he’d gotten it, but he turned out to be a maniac about all matters dashi, having studied under the great Yoshihiro Murata of Kyoto’s Kikunoi restaurant. (Murata uses only rishiri kombu, harvested at Kafuka beach on Rebun Island, off Hokkaido, not for one moment considering the utterly unacceptable rausu kombu from the nearby Shiretoko Peninsula, even though only about three experts on earth can tell the difference.) Murata is one of many Japanese chefs eternally engaged in theological dashi disputes, occasionally under the umbrella of the Tokyo-based Umami Information Center, about whether katsuo-bushi is best with or without its chiai, the dark meat near the blood line in a fresh bonito fillet.

I nearly broke my Benriner mandoline trying to shave the katsuo-bushi fillet. And the Microplane grater was a joke. But then I grabbed a carpenter’s plane from my workshop and produced divine—and expensive—dashi, according to the formula Kinch learned from Murata. This involved immersing precisely 30 grams of high-priced rishiri kombu in 1.8 liters of Fiji Water (Kinch likes Fiji for its low mineral content) >for 60 minutes at 140 degrees, as measured with a digital probe, and then removing the kombu, raising the temperature to 185 degrees, killing the heat, adding 50 grams of just-shaved katsuo-bushi, steeping for 10 more seconds and then straining everything through a piece of flannel—with its fine hairs pointing upward, not downward, no matter what.

Turning back to Tsuji, I then applied my dashi to a month’s worth of Japanese classics, like a sumptuous sake-simmered herring and a cucumber-and-wakame salad with “Two-Flavors Vinegar,” to which dashi contributed unexpected depth. At this point, I had the beginnings of a dashi repertoire, in case I wanted to apprentice in a 400-year-old Kyoto kitchen, but nothing of much use to a man cooking nightly for a wife and two young daughters.

A useful lesson presented itself at State Bird Provisions in San Francisco, where the sweetheart chef Stuart Brioza (an F&W Best New Chef 2003) enlists pretty young waitresses to wander around the dining room with platters, dim sum–style, of what he calls “albacore crudo and quinoa with bonito-rosemary aioli” and “tomato-dashi mushrooms with charred eggplant.” These dishes are heart-stoppingly delicious and, more important, not really Japanese at all. To Brioza, seaweed and dried fish are simply tools in a well-stocked global-cuisine toolbox. “We call it a choose-your-own-adventure style of cooking,” he says, “where you get this great larder full of ingredients, and then you start tasting with your eyes closed.”

In the case of kombu and katsuo-bushi, of course, you’re tasting for umami—but with a caveat. Both ingredients release their glutamates quickly and at water temperatures just below boiling. Bring either one to a full boil, or leave them in simmering water for too long, and they’ll begin releasing less appealing flavors. As a result, Brioza typically augments kombu and bonito with other “10-minute ingredients,” as he calls them, foods that also release their flavors quickly—tomato, rosemary, bay, garlic, ginger, scallion.

Once I understood the principle, I found Brioza’s quasi-dashi approach liberating. I improvised my own quasi-dashi, tossing in a little hickory-smoked bacon, whole garlic cloves mashed in their skins, fresh herbs, thin-sliced onion, even big curls of citrus zest. Doing like Brioza and bringing the pan to a bare simmer, I pulled it off the heat, let the mixture steep for 30 minutes, drained it, added bonito flakes to the resulting liquid, brought it all back to a simmer and drained again.

Just like that, I had the foundation for any number of dishes. Soups were easy—I added pulled pork, poached eggs, thin-sliced broccoli rabe and noodles, and suddenly, it was ramen night. I simmered grains like farro and quinoa in dashi instead of water for knockout grain salads. One of my favorite dashi moves now involves delicate fish fillets, like black cod: I sear the skin first, to get it crisp, then flip those fillets over and pour hot dashi into the skillet, along with maybe some white soy, mirin and citrus juice, until the liquid comes about halfway up the side of the fish. Served in a hot bowl with its liquid and a little wilted spinach, the cod is transporting.

Another benefit of these dishes, of course, is that they have ended my cluelessness about dashi itself—its origins, applications and historical importance. Which is a whole lot more than I can say for my continuing ignorance about credit-default swaps.

San Francisco writer Daniel Duane is a frequent contributor to F&W, The New York Times Magazine and Men’s Journal.

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