Here’s a concise guide to kombu and kelp, related sea vegetables (aka seaweed) that are easy to find in natural foods stores. You’ll find tips on how to best use them and a few recipes. Both kombu and kelp have a fairly mild flavor in relation to other sea vegetables; they taste somewhat salty and have a hint of ocean flavor.
The family of brown seaweeds called kelp (laminaria ochrole) is comprised of nearly nine hundred different varieties. Those most commonly marketed through the western natural foods market are Japanese kombu (kombu is actually the name for dried sea kelp) and Atlantic kelp, related varieties that have similar flavors and culinary usages.
Atlantic kelp was until some time ago marketed under the name Atlantic kombu, and it looks and tastes like the thinner varieties of Japanese kombu. It is harvested from the waters of the quiet bays of the northeast coast.
Most of the Japanese kombu market in the west comes from the waters off the coast of Hokkaido, the northernmost island of Japan. It’s also cultivated in Korea (called dashima) and China (called haidai).
According to Pacific Harvest: “Kelp seaweeds grow in underwater “forests” in shallow oceans. They require nutrient-rich water with temperatures between 6 and 14 °C (43 and 57 °F) and are known for their rapid growth rate. A kombu strip or kombu leaf is just a piece of kelp which has been dried flat for ease of use in the kitchen.”
How to buy and store
Packaged in wide, flat frond pieces, they’re both deep olive-green and are sometimes covered with a whitish powder, which is nothing more than a harmless substance called glutamic salt, considered a flavor enhancer or umami, which comes to the surface as the sea vegetables dry.
Store kombu and kelp in their original packaging, completely re-sealed once opened in a cool, dry, place. These sea vegetables will be shelf-stable for years if not exposed to moisture.
Kombu and kelp are nutritionally similar. Both are rich sources of minerals such as calcium, iron, magnesium, potassium, and iodine, as well as the trace minerals copper and zinc.
These sea vegetables provide a good supply of vitamins A, C, and D, and several of the B vitamins, including riboflavin, niacin, and pantothenic acid. See more about the nutritional aspects of these sea vegetables. Here’s lots more about the nutritional aspects of these sea vegetables.
How to use kombu and kelp
To use reconstituted: Reconstitute kombu and kelp by cutting into 4- to 5-inch lengths with kitchen shears and soaking in warm water for 5 to 10 minutes. Then the sea vegetable is ready to be cut further into strips or small squares to use in recipes like stir-fried vegetables, bean stews, soups, hot cooked grains, or simple Asian noodles flavored with miso or soy sauce.
Some uses don’t require reconstituting, however. Here are a few:
Kombu dashi: Kombu is especially well known as an important element in making this basic Japanese broth, called dashi, which can be served on its own or as a base for miso soup:
Combine 4 to 5 cups water with a 5-inch piece of kombu and 5 to 6 fresh or dried shiitake mushrooms. Bring to a slow boil, then remove from the heat and let stand for 30 minutes. Strain and reserve the kombu and mushrooms for other uses. Flavor the stock with soy sauce and use it for cooking vegetables or serve simply as a light broth, adding cooked noodles such as jinenjo, somen, or udon, and/or diced tofu and minced scallions.
Following on from this, here’s this site’s recipe for Traditional Japanese-Style Miso Soup, made vegan without bonito (fish) flakes.
Legume tenderizer: Both of these related seaweeds may be used as a tenderizer for cooking beans, peas, and lentils. They contain a substance (glutamic acid) that softens the beans, helping them to cook more quickly and making them more digestible. Simply add a 4-inch piece of kelp or kombu per every pound of dried beans used and cook in your favorite manner (stovetop, slow cooker, Instant Pot®) until the beans are tender.
Noodle enhancer: Incorporate strips of reconstituted kombu or kelp into your favorite Asian-style stir-fried noodle dish or broth-based noodle dish. Here’s Vegan Ramen with Miso Shiitake Broth — you’ll want to use the optional sea vegetable!
Kombu or kelp chips: Cut dried kombu or kelp into 1- to 2-inch squares with kitchen shears. Bake at 350ºF for 15 to 20 minutes, or until lightly browned and crisp. Serve as a snack with a soy-based dipping sauce or a bottled or homemade teriyaki sauce.
Seaweed Salad: Reconstituted kombu or kelp is part of many traditional Asian-style seaweed salads. Here’s an appealing sesame-flavored Chinese Seaweed Salad.
More sea vegetable guides
And see more Good Food Guides on this site.