What Is Kombu?
Kombu is made by harvesting and drying several types of brown kelp (giant seaweed), especially Saccharina japonica. It is sold in thick, tough, dark green-brown sheets; the whitish residue (mannitol) on the surface is natural and adds flavor.
It is a main ingredient in dashi stock, a staple of Japanese cuisine; its high glutamic acid content gives dishes a deep umami flavor.
Kombu Nutrition Facts
According to general kelp data, 100 g of raw kombu contains approximately 43 kcal of energy, 1.7 g of protein, and 9.6 g of carbohydrates; detailed nutrition data specific to kombu is limited in available sources. Kombu is known as one of the seaweeds with the highest iodine content.
What Are the Benefits of Kombu?
As part of a balanced diet, kombu is a sea vegetable that can provide iodine and fiber; its glutamic acid content may help reduce the amount of salt needed in dishes. Adding it to the cooking water for legumes is also a traditional practice believed to aid digestion.
This is general information; kombu is a food and does not replace medical treatment. Because of its very high iodine content, frequent consumption in large amounts may affect thyroid function; moderation is advised for people planning to consume it regularly.
How to Choose Kombu
Good-quality kombu is thick, tough, and dark in color; its thin whitish surface layer is a natural component that indicates quality, not mold.
- The sheets should be thick and brittle; pieces that are overly flexible or soft may have absorbed moisture.
- The package should be intact and within its date.
- Choose wide sheets or an opened package for dashi, and thinly cut kombu for garnish.
How to Store Kombu
Dried kombu can be stored for a long time in a cool, dry, dark cupboard without spoiling. Soaked or cooked kombu should be eaten within a few days if kept refrigerated in an airtight container.
Using Kombu in the Kitchen
Kombu is most often used to make dashi stock, add flavor and nutrients to the cooking water for legumes and grains, and in pickling and marinades. Wipe its surface lightly with a damp cloth; do not wash it, as washing removes the flavorful residue.
How to Make Dashi
Soak a piece of kombu in cold water for at least 30 minutes, preferably overnight; then heat it slowly and remove the kombu just before the water boils. Boiling it too long or removing it too late makes the stock slightly bitter.
How to Use Kombu When Cooking Legumes
Adding a piece of kombu to the cooking water for legumes such as chickpeas and lentils is a method traditionally believed to add flavor and aid digestion; at the end of cooking, the kombu can be removed and used separately.
What Recipes Use Kombu?
Kombu is often used in dashi stock, miso soup, kombu pickles (tsukudani), and as a flavor enhancer when cooking chickpeas or lentils.
Frequently Asked Questions
What is the difference between kombu and wakame?
Kombu is a thick, tough type of kelp, usually simmered to make dashi stock; wakame is thinner and softer, and is eaten directly in soups and salads.
Should kombu be washed?
No. The whitish residue on its surface adds flavor; lightly wiping it with a damp cloth is enough instead of washing it.
How long should kombu soak for dashi?
For the best results, it should be soaked in cold water for at least 30 minutes, ideally for several hours or overnight.
Should used kombu be discarded?
No. After the dashi has been extracted, the remaining kombu can be cut into thin strips and cooked with soy sauce to make a side dish called tsukudani.
Where is kombu sold?
Dried packages can be found at Asian markets, in the international foods sections of large grocery stores, and through online retailers.