Glossary - Ingredients

Kombu / Kelp

GlossaryKombu

A seaweed used to make dashi Japanese broth in Japanese cuisine, also eaten as simmered dishes and tsukudani (a preserved food cooked with soy sauce)

What is kombu?

Kelp, also known as kombu (昆布 in Japanese), is a type of seaweed that is often sold as sun-dried product, and is rehydrated in water before use. Kombu-dashi, made by heating kelp in water, has a unique umami flavor and is one of the main dashi used in Japanese cuisine. The kelp used to make soup stock can be removed from the dish or left in the hotpot, such as in dishes like oden or yudofu. However, the kelp used for soup stock is generally thick and fibrous, making it hard and unsuitable for eating on its own. Thin, soft kelp is cooked in soy sauce and made into tsukudani, or added to simmered dishes as an ingredient. Other types include oboro kelp, which is made by thinly shaving each piece of kelp by hand, and tororo kelp, which is made by thinly shaving the sides of a block of stacked kelp  being pressured by a machine. Oboro kelp has firm fibers, so it can be used to wrap onigiri instead of seaweed nori. Tororo kelp is fluffy and can be added to clear soups and udon.

Storage to prevent food loss

In the case of sun-dried kelp, cut it into pieces of about 15 cm, seal it in a can or bottle, and store it in a dry, dark place with low humidity. It can also be stored in the refrigerator or freezer.

Trivia

There are many different types of kelp, but more than 90% of the kelp in Japan is harvested off the coast of Hokkaido. Rishiri kelp, Rausu kelp, and Hidaka kelp, which are often used for dashi purposes, are each named after the place in Hokkaido from which they are produced.

Cooking Basics

Dashi - how to make from kombu and dried bonito flakes

Ingredients (for 800 ml / 27 fl. oz. of dashi)

Kombu/kelp
10 g (3 × 25 cm / 1.2 x 10 in.)
Katsuobushi/bonito flakes
20 g (0.7 oz.)
Water
1000 ml (33.8 fl. oz.)

Directions

Soak the kombu in water for 30 minutes, then heat over medium heat. Just before the water comes to a boil, remove the kombu and turn off the heat. After a few minutes, add in the bonito flakes and allow to sit for 2 minutes.  Place a dampened paper towel over an all-purpose strainer and strain the dashi.

Dashi - how to make from kombu

Ingredients (for 880 ml / 27 fl. oz. of dashi)

Kombu/kelp
15 - 20 g (0.5 - 0.7 oz.)
Water
1000 ml (33.8 fl. oz.)

Directions

Soak the kombu in water and let sit for 30 minutes, then heat over medium heat.  When the water comes to a boil, lower the heat and allow to simmer for 7 to 8 minutes.

Dashi (kombu and bonito) prepared using a microwave

This method is convenient when you do not have time to soak or simmer the kombu. Place a 5 cm (2 in.) piece of kombu, a handful of dried bonito flakes, and 400 ml (13.5 fl. oz.) of water into a heat-resistant bowl, cover loosely with plastic wrap or a lid, and microwave (600W) for 3 minutes.

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