Food Forum
Vol. 29 No. 2  July 2015


Making Katsuobushi

Katsuobushi shaver, shavings and fillets
Katsuobushi shaver, shavings and fillets

Katsuobushi, dried bonito, is an essential ingredient in Japanese cuisine. Extracting moisture from the fresh fish produces in it a highly condensed umami, which is the basis for the dashi stock used in making Japanese dishes such as miso soup and soba dipping sauce. Katsuobushi shavings are typically sprinkled over tofu or boiled vegetables. Freshly shaven flakes are best, but pre-packaged flakes, which retain freshness, are readily available. Japan’s traditional method of making honkarebushi, the highest-quality katsuobushi, is labor-intensive, and takes about six months to complete. The basic steps are as follows:

  1. The head, internal organs and excess flesh are removed from the raw bonito; the fish is then cut lengthwise into four fillets.
  2. The fillets are boiled in metal baskets for about 90 minutes in hot (80-90℃) water; they are then cooled, deboned, and much of their skin and fat are removed. At this stage, the water content is about 68%.
  3. The fillets are placed in wooden-lidded baskets and wood-smoked for about one hour, then allowed to cool. This process is repeated 10-15 times; the fish is then dried in the sun for a half-day, and set aside for a few days. By now, the water content is reduced to about 28%.
  4. After cleaning the fillets, they are laid out to dry again in the sun for a day or so, then placed in a culture room where they are coated with a special mold and stored for about two weeks; they are then dried again in the sun, and the mold is removed. This molding/drying process is repeated over several months. The end result is honkarebushi fillets of dried bonito, with a water content of less than 18%―the ultimate form of katsuobushi as a fermented food.