June 03, 2021

Konbu Dashi (昆布だし)

Konbu Dashi (昆布だし)
Main Umami Ingredient: Glutamic acid
Extraction method: Cold, boiling or boiled water

90% of Japan’s konbu (thick edible kelp) is harvested in the northernmost prefecture of Hokkaido. Mineral-rich, ice cold water flowing down from Siberia provides a nutrient-dense environment for some of the world’s best konbu to grow. Each specific cultivation area produces a different tasting konbu based on the unique characteristics of the waters.

Tough and difficult to digest on its own, konbu must be cooked for a long time, which also draws out its high amount of glutamic acid, an amino acid responsible for umami. It has a subtle flavor and produces a clean, clear dashi that is typically used in the Kansai region of Japan and is a great choice for vegetarians and vegans.

There are four main types of konbu:

Ma-konbu (真昆布, lit. “true kelp”): The most popular yet high quality konbu, its thick leaves are wider than other konbu and has a light brown color. It has a refined sweetness, deep aroma and rich umami flavor, and produces a clean, dark brown dashi with a hint of green coloring. The price varies based on the production area and the growing method (natural, which makes up 10% of the total available, or from seedlings which are farm grown before being returned to the sea).
Hidaka konbu (日高昆布): Not typically used for dashi (except in the Kanto region), hidaka konbu is more commonly found in kobumaki (kelp rolls) or tsukudani (simmered in soy sauce and mirin). It softens easily and absorbs surrounding flavors well. It’s relatively inexpensive and is therefore only found growing naturally since there is no merit in cultivating it.
Rausu konbu (羅臼昆布): Characterized by its cloudy, thick, strong flavored dashi, rausu konbu is best used for stews and nabe, and is not typically used for soups, except in the Kanto region where strong seasonings tend to be favored. It’s also commonly made into konbu cha (kelp tea), snacks and tsukudani. The natural harvest is very small, so it is often sold at a high price.
Rishiri konbu (利尻昆布): Rishiri konbu produces a clear dashi that is suitable for soups, nabe (hot pot), yudofu (boiled tofu) and pickles such as senmai-zuke (pickled turnip). Rishiri konbu produced on Rishiri and Rebun Island is called shimamono, and is prized in Kyoto for its rich dashi. However, the price is very expensive. Those from Wakkanai and Soya on the opposite shore are called jikata, and are often used for cooking and udon soup stocks. Most supermarkets and department stores carry this type, but since there are no labeling requirements, it can be difficult to distinguish the two.