Kombu: what you need to know about this Japanese seaweed

by Joost Nusselder | Updated:  August 24, 2022

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There are many popular Japanese toppings. Seaweed or kelp is one of the most common umami-flavored foods.

It is used to garnish all types of savory dishes!

Japanese cuisine is known for its use of sea vegetables. These are nutritious and flavorful, therefore popular among many health-conscious people.

Favorite Asian Recipes
Favorite Asian Recipes

Kombu kelp is one of the most common sea vegetables used in Japanese cooking.

Kombu- what you need to know about this Japanese seaweed

In this article, I’m sharing all the information you need to know about what kombu is, how it’s used in East Asian cooking, and why it’s so popular (hint: it’s super nutritious!)

What is kombu?

Kombu (konbu, 昆布 in Japanese) is Japanese edible seaweed or kelp. It is commercially cultivated and harvested from the sea. It has a distinctive umami taste and is rich in minerals. It is used as a condiment, garnish, and ingredient in many Japanese dishes.

  • Kombu belongs to the seaweed family Laminariaceae and is considered a type of edible kelp.
  • It has a dark brown color in both its fresh & dried form
  • It is closely related to other edible seaweeds such as wakame, arame, and hijiki.
  • Kombu kelp has an umami flavor.
  • It’s used as a base for many kinds of broth and as a seasoning.
  • Japanese Kombu is made from kelp that’s been dried and cut into thin strips.

It has been used for centuries in traditional Japanese cooking.

It’s often used to make dashi, a type of broth that’s used as a base for many Japanese dishes.

The reason why kombu is so popular in Japanese cooking is because of its high nutritional value.

It’s a good source of dietary fiber, minerals (including iodine, magnesium, and calcium), and vitamins (especially vitamin K).

Japan is the world’s largest kombu consumer and producer. It’s estimated that the Japanese consume about 10,000 tons of kombu per year!

But, kombu is not quite the same as wakame and Western-type kelp.

What does kombu mean?

The word kombu in English means dark brown seaweed or kelp from the brown algae family Laminaria, of the class Phaeophyceae.

In Japanese, it’s spelled konbu and means the same thing.

What does Kombu taste like?

Kombu is also known for its umami flavor. It’s best described as mild, with a slightly sweet taste and lots of savoriness.

Umami is a savory taste that’s often described as “meaty” or “delicious.” It’s one of the five basic tastes, along with sweetness, sourness, bitterness, and saltiness.

The umami flavor of kombu comes from its high concentration of glutamic acid, an amino acid that’s responsible for the taste of umami.

Kombu also contains inosinic acid, which is another amino acid that enhances the umami flavor.

Types of kombu

There are six kombu varieties:

Ma-Kombu

This type also goes by the name yamadashi kombu, and it has a lighter brown color. It’s the most common type of kombu, and it’s used to make dashi broth.

Hidaka-Kombu

This type has a very dark color, but it’s softer than the other varieties.

Rausu-kombu

This variety is wide compared to the other and has thin fronds. It releases more flavor than the others; hence it’s excellent for dashi soup stock.

Rishiri-kombu

This is premium kombu from Japan’s northern island. It is very flavorful, and the rich umami taste makes it most suitable for dashi.

Hosome-kombu

This kombu is wrinkled and has a strong umami flavor. It is used in simmered dishes and as a wrapping for sushi rolls.

Naga-kombu

This kombu is very long, and it can be up to 3 meters in length! It has a strong flavor and is also known as cat’s foot seaweed.

What’s the origin of kombu?

In Japan, kombu has been consumed as food for thousands of years because it’s always been readily available for fishermen.

Kombu is thought to have originated in the cold waters off the coast of Japan.

In ancient times, kombu was used as a currency and was also given to samurai warriors as a sign of respect.

Researchers have discovered that wakame seaweed and kombu were part of Japan’s cuisine already in the Jōmon period (14000-300 BCE).

Wood strips from the imperial capital of Fujiwara-ky (694–710) and the Man’yōshū, the earliest collection of Japanese poetry, compiled in 759, have the earliest written allusions to the cuisine.

At this time, Kombu would have been manually picked, dried, or used fresh in broths and soups at this time.

During the Muromachi period, which lasted from 1336 to 1573, new drying procedures were created, allowing kombu to be preserved for extended periods of time.

By the Edo era (1603–1867), kombu was a common element all over the nation. Kelp farmers were still gathering natural kelp from the sea during this time.

The crop wasn’t grown until the first decades of the 20th century. As a result, kombu became more affordable and accessible.

Buy dried kombu online

(view more images)

These days, kombu is available at all Asian grocery stores or online.

I like the sundried kombu sheets from YOHU that is pure seaweed without any preservatives.

How to serve kombu

Kombu can be served in many different forms. While it can be eaten raw, it’s best served from the dried form.

Fresh kombu refers to the edible seaweed that’s still attached to rocks in the ocean. It has a dark green color and a slimy texture.

Dried kombu is probably the most popular. It is available in sheet form, known as kombu sheets or as shredded kombu.

The kombu sheets are used to make dashi while the shredded kombu is often used as a garnish or seasoning.

Pickled kombu is another popular form. It’s made by pickling kombu in vinegar, soy sauce, and mirin (a Japanese cooking wine).

Powdered kombu is another form of kombu that’s available. It’s made by grinding dried kombu into a powder.

Kombu tea is a popular beverage made by steeping kombu strips in hot water. It’s believed to have many health benefits, such as helping with digestion and boosting metabolism.

Where is kombu cultivated?

Kombu thrives in cool, nutrient-rich waters. It’s most commonly cultivated in the cold waters off the coast of Japan, Korea, and China.

In Japan, kombu is grown in the Hokkaido region. This region is known for its pristine waters and ideal growing conditions for kombu.

Kombu cultivation is a centuries-old tradition in Japan. The first recorded kombu cultivation methods date back to the seventh century!

Kombu is also cultivated in Korea and China. In recent years, kombu cultivation has begun in other countries, such as Iceland, Canada, and the United States.

The majority of kombu that’s sold commercially is still cultivated in East Asia.

How is kombu harvested?

Kombu is hand-harvested from the ocean. It’s a labor-intensive process that’s often done by divers.

The kelp seaweed is cut from the rocks it’s attached to and then brought to the surface. After it’s harvested, the kombu is cleaned and then dried.

Kombu can be dried in the sun or by using an arator. Once it’s dried, it’s usually cut into strips or shredded.

Kombu that’s sold commercially is usually wild-harvested. However

What foods is kombu used in?

Dried kombu is often used to make kombu dashi, a type of broth that’s used as a base for many Japanese dishes.

It can also be used to flavor stews, soups, and simmered dishes.

Kombu is often used in vegetarian and vegan cooking as a way to add savory umami flavor.

It’s also used when making miso soup, a popular Japanese soup that’s made with miso paste, tofu, and vegetables.

This edible sea vegetable can really be added to any noodle soup.

Kombu can also be eaten on its own or turned into shio kombu which is kombu that’s been soaked in soy sauce and mirin.

It’s a popular ingredient in onigiri, a type of Japanese rice ball.

The kelp is also used to make many kinds of pickles, such as takuan and umeboshi.

Kombu rolls and kombu chips are also popular ways to enjoy this delicious seaweed.

What are the health benefits of kombu?

Kombu is renowned for its excellent nutritional value, so it’s considered a “superfood.”

It includes high concentrations of various vitamins and minerals that are excellent for your health, including potassium, calcium, and iodine.

Kombu is also a good source of dietary fiber, which is important for maintaining a healthy digestive system.

This seaweed also helps lower cholesterol in the blood and counteracts hypertension.

The vitamins found in kombu, such as vitamins A, B1, C, E, and K, promote vital bodily processes and a strong immune system.

Vitamin A supports a healthy immune system, reproductive system, and vision. Additionally, it promotes healthy heart, lung, kidney, and other organ functions.

Vitamin B1 provides energy, boosts vitality, heart health, and cognitive function.

High levels of vitamin C aid the maintenance of cartilage, bones, and teeth, as well as the healing of body tissues and the absorption of iron.

Vitamin E helps maintain healthy skin and vision.

Finally, vitamin K produces the proteins necessary for strong bones and proper blood coagulation.

Another thing to note is that kombu promotes gut health.

Since it’s a source of fiber, kombu is also believed to help with gut health by boosting the number of “good” bacteria in the digestive system.

Additionally, kombu has glutamic acids that can aid in the breakdown of carbohydrates in foods like beans.

As such, it can lessen gas production from the breakdown of these foods, resulting in less bloating and improved digestion.

Kombu’s iodine content is important for supporting healthy thyroid and hormone production.

These systems are crucial for controlling the body’s metabolic functions. We must make sure we get adequate iodine in our diet because it cannot be produced by the body.

Iodine shortage can cause dry skin, hair loss, hypothyroidism, and problems with the reproduction system.

Similar foods

When it comes to kombu, it’s only one kind of seaweed. There are other types of seaweed that have the same umami flavor.

Other seaweed varieties include nori, wakame, arame, and hijiki.

Nori is probably the most popular type of seaweed after kombu. It’s used to make sushi rolls and onigiri.

Wakame is another type of seaweed that’s often mistaken for kombu, but it’s not the best for cooking kombu dashi.

Instead, wakame is often used in salads and soups as a salty topping.

Arame is a milder-tasting seaweed that can be used in simmered dishes and soups.

Hijiki is a seaweed that’s often used in pickling recipes or simmered dishes.

FAQs

Is kombu just dried seaweed?

Kombu is a type of kelp that’s typically harvested off the coast of Hokkaido, Japan.

It doesn’t necessarily have to be dried. However, most people refer to dried seaweed when talking about kombu.

Most kombu is sold in dried form at health food stores and Asian shops.

Is it OK to eat raw kombu?

Yes, it’s safe to eat raw kombu. However, it has a very rubbery texture which can be unpleasant to chew on.

Which kombu is best?

Experts recommend hidaka kombu or ma kombu for cooking.

Hidaka kombu has a more robust flavor, while ma kombu is more delicate.

Both can be used to make dashi and soup stocks, but ma kombu is better suited for light-flavored dishes, while hidaka kombu is better for hearty stews and braises.

Why is kombu slimy?

Mannitol creates the slime when it comes into touch with water and Kombu sheets.

The umami flavor of kombu is mostly dependent on the existence of mannitol deposits. Hence moderate rinsing is advised rather than vigorous washing.

How do you store kombu?

Kombu must be stored in airtight containers in a cool, dry place. It can be refrigerated for up to six months or stored in the freezer for up to one year.

Does kombu expire?

As long as it’s kept in a dry, cool place, kombu doesn’t go bad. However, it will lose its flavor over time.

Final thoughts

Dashi kombu, the kombu roll, dried kombu strips, and powder are just some ways to consume this edible seaweed.

Kombu is an ingredient that’s often used in Japanese cuisine. It has a unique umami flavor that’s perfect for making dashi.

It has a long history in Japan’s food history because it’s tasty and also very nutritious.

Next, learn about Aonori dried seaweed powder & flakes to season your dishes

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Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.