Konbu (also spelled as "kombu") is a tall leafy plant growing from the sea floor in cold, shallow waters off the coast of northern Japan, especially Hokkaido. The deep olive brown leaves become one to two meters long and vary in width from 5 to 30 centimeters. Konbu is partly cultivated and partly harvested from natural sources, from June to October. Konbu is washed with seawater and then cut into 1 m long sheets and dried in the sun. After drying it becomes stiff and dark green.
Konbu has been used as a food source since the beginning of Japanese civilization. It contains important minerals, including iodine, vitamins, protein and dietary fiber.
In fact, the Japanese cuisine could not exist without konbu, as it is the main ingredient for dashi, the stock that forms the pillar of the Japanese kitchen.
Prominent types of konbu and their uses are:
- Ma konbu (Saccharina japonica). From the Straits of Tsugaru and the Southwestern part of Hokkaido. The most popular, high-quality konbu. Has a refined sweetness. Used for making high-quality dashi, but also for shio konbu, oboro konbu and tororo konbu.
- Rausu konbu (Saccharina diabolica). From Rausu in Northeastern Hokkaido. Fragrant and soft. Used for making high-quality refined dashi. Also processed into kobu-cha (konbu tea) and su-konbu (pickled kelp).
- Rishiri konbu (Saccharina ochotensis). From Rishiri, Rebun and the Wakkanai coast in Northwestern Hokkaido. A savory type used for making a clear dashi with a rich taste and tororo konbu.
- Hosome konbu (Saccharina religiosa). From the Oshima Peninsula (southernmost part of Hokkaido). Is thin and has a slippery texture so that it is best suited to make tororo konbu rather than dashi. Also used to make shio konbu or konbu for tsukudani.
- Naga konbu (Saccharina longissima). From the Kushiro area in Northeastern Hokkaido. Can get 15 meters long. Soft and therefore used for konbu maki (fish etc. rolled in konbu), as well as for tsukudani, oden and as ni-konbu (boiled kelp).
- Mitsuishi or Hidaka konbu (Saccharina angustata). From the Hidaka coast in Southeastern Hokkaido. Is very soft and therefore used many prepared dishes, for konbu rolls, or eaten as such. Also used for more common type of dashi.
Uses of konbu:
- As basic ingredient for dashi.
- Tororo konbu, konbu that has been soaked in vinegar, dried and shaved. It can be used as a wrapping for sushi rolls (makizushi), or used in clear soups (suimono).
- Oboro konbu, very similar to tororo konbu above. Used in wan-mono and in sunomono.
- Konbu maki, fish as herring (nisshin) wrapped in konbu.
- Kobu jime, a cooking technique whereby the ingredients (usually fish) are wedged between sheets of kelp and kept for a night in the refrigerator.
- Kobu cha, tea made from konbu
- Shio konbu, salt konbu, a popular snack and in the past an alternative to chewing gum
- Su konbu, pickled kelp, also a snack.
[Dried konbu sheets from Wikipedia]