Kelp Seaweed : Konbu
Konbu is the one of most important seasonings in the Japanese pantry. It’s arguably what gives Japanese cuisine its distinct taste. A type of edible kelp, it has some of the most naturally occurring umami, in the form of glutamate, of any food. When the umami of dried konbu is extracted in water or other liquid, it creates a base seasoning that enhances the flavor of all foods and dishes. This shouldn’t come as much of a surprise. Given that all life began in the sea, it makes some sense that the most powerful natural source of umami—nature’s essential goodness of flavor—can be found there too, permeating the sea and enriching other life forms with its deliciousness.
Konbu doesn’t grow in the Seto Inland Sea. It’s found only in the cold, deep, fast-moving waters around the island of Hokkaido in the north of Japan. But its use in the Setouchi kitchen goes as far back as 2,000 years ago, when it was traded for the sea salt produced in the Setouchi region, which couldn’t be made in Hokkaido because of its cold, cloudy climate.
In the Setouchi, konbu is used to make a simple konbu dashi, which is the base stock most commonly used for all kinds of dishes. It’s also used to make pickles, dressings, and sauces and as both a seasoning and ingredient in simmered, braised, rice, and noodle dishes.
Varieties of Konbu & Their Uses
There are three main types of konbu used in the Setouchi kitchen, with each variety having different flavor characteristics and range of possible. Listed in order of the amount of their naturally occurring glutamate, the three types of konbu and their uses are:
Ma-Konbu (真昆布)
Ma-Konbu is harvested from the sea near the city of Hakodate in southeastern Hokkaido. Its name means “True Konbu.” The “ma” prefix (真) is not just a statement about its quality, which is excellent. “Ma” is used in front of the names of many kinds of foods in Japan to signal that this variety is the one by which all other varieties are benchmarked. Ma-Konbu has the highest amount of naturally occurring glutamate of all types of konbu and produces an elegantly aromatic, clear, transparent dashi stock with a deep yet subtly rich flavor that has a faint sweetness.
It’s the konbu most often used in the Osaka area and also widely across the rest of the Setouchi because it creates the finest konbu dashi; one that works well with all seasonings and complements the flavors of all foods. It can be used for any type of dish: clear soups, yu-dofu (simmered tofu) and other hot pots, sauces, simmered dishes, pickles, and rice and noodle dishes. It can also be used to make combined dashi stocks: katsuo-konbu, shiitake-konbu, and iriko-konbu dashi stocks.
Ma-Konbu is also known as Yamadashi-Konbu (山出し昆布).
Ma-Konbu
Rausu-Konbu (羅臼昆布)
Coming from the sea off the town of Rausu on the south side of Shiretoko Peninsula in northeastern Hokkaido, Rausu-Konbu is called the “King of Konbu” because it produces the richest, strongest-tasting stock of all types of dashi konbu: one with an assertive aroma, sweet taste, and pale yellow, cloudy color. These characteristics are due to the way Rausu-Konbu is processed, which also causes it to have a slightly greater umami content than Ma-Konbu. While all other types of dashi konbu are simply laid out on the beach after harvesting to be dried by the sun in four to five hours, Rausu-Konbu is cured in its own salt for about three weeks. It’s first dried on the beach, allowed to be moistened each night with dew, and then stretched and dried again the next day. In effect, it becomes a “sun-dried tomato” version of konbu. Rausu-Konbu’s intensely concentrated richness and heightened, fermented depth of flavor are reflected in the large amount of chalky white umami substance on its surface.
Rausu-Konbu is not typically used as a base ingredient for combined dashi stocks because of its strong “meaty” kelp flavor. Instead, it’s used as a konbu-only dashi in hot pots, noodle soups, salt ramen, and lightly seasoned dishes that benefit from its deep, rich flavor. However, if you want to experiment with using a konbu dashi as a base seasoning for cooking richly-flavored, meat-laden Western dishes, try using Rausu-Konbu dashi and see what it does. Vegetarian and vegan cooks may also want to try cooking with Rausu-Konbu to enrich the flavor of their dishes with this hearty sea vegetable stock.
Rausu-Konbu
Rishiri-Konbu (利尻昆布)
A narrow, frilly-edged konbu, Rishiri-Konbu is collected from the Sea of Okhotsk off the northwestern region of Hokkaido around Rishiri and Rebun islands. Containing about one-third less glutamate than Ma-Konbu and Rausu-Konbu, Rishiri-Konbu creates a lighter-tasting, very clear dashi stock with an elegant fragrance and slightly salty taste. Like Ma-Konbu it complements all foods and adds a subtle richness of flavor to any dish. It can be used for anything and is in the kitchens of Kyoto, where it’s used to create the light, but complex dishes of kaiseki cuisine. That’s, in part, because Rishiri-Konbu is essentially a “seasoning” konbu; one whose well-balanced, light, salty flavor performs well in concert with other seasonings. For example, it’s particularly good for making a katsuo-konbu dashi and other combined dashi stocks. Rishiri-Konbu may be the best “cross-over” konbu; one that can be used as a base seasoning in all kinds of cuisines because of its light taste and compatibility with other foods.
Rishiri-Konbu is a tougher konbu than the others when dried, and needs to be soaked for 60 minutes before using to make a dashi stock by the hot method.
Rishiri-Konbu
There is a fourth konbu used in Japanese cooking called Hidaka-Konbu (日高昆布). It’s much weaker than the others in umami content, having only about one-third the glutamate, and isn’t used to make a stand-alone konbu dashi. Instead, it is used to make a combined katsuo-konbu dashi, which is also heavily seasoned with other umami-rich seasonings like mirin, soy sauce, and miso. It’s mainly used in Tokyo and Japan’s northern Tohoku region.
Where to Buy
You can find all of the varieties of konbu at pretty much every supermarket and department store in the Setouchi as well as across Japan. Abroad, look for it in Japanese and Asian food stores, online, and through specialty food distributors.