Umami is the most important element of Japanese cuisine. The substance that gives rise to umami was discovered in 1908 by the Japanese scientist Kikunae Ikeda in dashi kombu (kelp). Since then, kombu has become recognized worldwide as the base ingredient of dashi, which supports the umami of Japanese cuisine.

Kombu is only caught in the Tohoku region and northwards, and in the past, it was a valuable trading item and was treasured. In the Heian period, it was presented as a tribute to the imperial court. Later, in the Kamakura period, production increased, and in the Edo period, many processed products were created to meet the sudden increase in demand, and it became widely popular among the general public.

Kombu is mainly dried and used to make dashi, but there are also many processed products such as kizami kombu, tororo kombu, and oboro kombu, and it is often used in local dishes such as kombu maki and Matsumae zuke. It is also used for kobujime in sushi.

If you want to make dashi using only kombu, we recommend Rausu kombu, which makes a rich dashi. Suppose you want to make a combination of dashi. In that case, we recommend Rishiri kombu or Makombu, which have a strong presence but don’t overpower the other ingredients, and make a clear dashi. If you want to make dashi quickly and easily, then Makombu powder is the best choice. The main production area is Hokkaido, and the approximately 15 or so varieties of kombu that are eaten are harvested within three years.

 

Now let’s take a look at some of the main types of kombu.

Rausu Kombu（羅臼昆布）

This is a brownish-red kelp that is harvested from the coast of the Shiretoko Peninsula and is characterized by its large leaves. Although the dashi broth becomes cloudy when dashi is made from this kelp, it is highly popular in the Kanto region as dashikombu and is used as a high-end product alongside Makombu, as it produces strong umami and aroma.

The area where Rausu kombu can be harvested is small, and it is a very rare type of kombu (harvested amount: about 200 to 500 tons per year). Rausu kombu is the most expensive type of kombu.

Rausu kombu is divided into two types: Kurokuchi（黒口）, which has a dark brown outer surface, and Akakuchi（赤口）, which has a reddish-brown outer surface. Kurokuchi has a better appearance and is more expensive than Akakuchi. The flavor is almost the same.

 

Rishiri kombu（利尻昆布）

Rishiri kombu mainly produced in the area from northern Hokkaido is a dark green kelp, including Rishiri Island and Rebun Island to Abashiri in eastern Hokkaido.

It has a crisp texture and a stronger aroma than kombu and is characterized by the elegant, clear dashi it makes. It has long been prized in Kyoto’s traditional restaurants and is used in dishes such as Yudofu (boiled tofu) and Senmaizuke (pickled sliced radish). After being used to make dashi, it can also be used in simmered dishes and Tsukudani (food boiled in soy sauce). Rishiri konbu is graded into four levels (1-4) according to its quality (thickness, width, length, color, etc.). It is said that the higher the grade, the better the dashi it makes.

 

Makombu（真昆布）

Makombu is mainly produced in southern Hokkaido and the Sanriku region and makes a clear dashi with no strong flavor. Because it is thick, it is also used for processing into products such as Oboro konbu （おぼろ昆布）and Tororo konbu（とろろ昆布）. There are two types: “Kuroguchi-hama（黒口浜）”, which has a black cut surface, and “Shiroguchi-hama（白口浜）”, which has a white cut surface. The natural Shiroguchi-hama caught at the Osatsubehama in Kayabe, Hokkaido, is considered to be the highest-end product.

 

Hidaka Kombu（日高昆布）

Hidaka Kombu is a dark green kombu mainly produced in Hokkaido’s Hidaka region and is also called Mitsuishikombu（三石昆布）. It is suitable for Kombumaki, Tsukudani and other simmered dishes and side dishes because its fibers are soft and it cooks quickly. It also makes good dashi, and because it can be used for both simmered dishes and dashi, it is widely used in ordinary households.

It is the most commonly produced type of kombu. Most Hidaka kombu is shipped without being flattened. The surface is uneven compared to Rausu kombu and Rishiri kombu, which are flattened.

Hidaka kombu is graded into 1 to 5 levels according to its quality (thickness, width, length, color, etc.). The higher the grade, the thicker it is, so it is said to make a good broth and is delicious to eat. We recommend grade 1 for gifts and grade 3 or above for home use.

 

Hosome kombu（細目昆布）

 

Hosome kombu harvested along the coast of the Sea of Japan in Hokkaido is a processed variety. It is narrow and is harvested in the first year. It is black in color, and the cut surface is the whitest of all kombu. It has a strong stickiness and is used in Tororo kombu and other products.

 

Atsuba kombu（厚葉昆布）

Atsuba kombu harvested along the coast east of Kushiro is a processed variety of kombu, in the same way as Nagakombu. It is used in processed products such as kombu maki and Tsukudani. It is also called Gagome kombu.

 

Gagome kombu（籠目昆布）

Gagome kombu harvested in the Hakodate area is a processed variety of kombu. It has a basket-like texture and is very sticky. It contains a lot of fucoidan, a dietary fiber that is said to have anti-cancer properties, and in recent years it has attracted a great deal of attention as a health food. It is used to make Tororo kombu and Matsumae zuke.

For your reference.