Katsuobushi

Katsuobushi shavings from a package

Katsuobushi (鰹節 or かつおぶし) is the Japanese name for dried, fermented, and smoked skipjack tuna (Katsuwonus pelamis, sometimes referred to as bonito).

Shaved Katsuobushi and dried kelp - kombu - are the main ingredients of dashi, a broth that forms the basis of many soups (such as miso) and sauces (e.g., soba no tsukejiru) in Japanese cuisine.

Katsuobushi's distinct umami flavor comes from its high inosinic acid content. Traditionally made katsuobushi, known as karebushi, is deliberately planted with Aspergillus glaucus fungus in order to reduce moisture.

Traditional production process

Katsuobushi is sold in wood-like blocks

Raw bonito is gutted and sliced. The fillets are arranged in a basket and simmered for one hour just below boiling. Fat, scales, and bones are removed

The fillets are then smoked using oak, pasania, or castanopsis wood until the fish has dried. Tar and dirt are then shaved from the surface and the fish set to further dry in the sun. The fish is then sprayed with Aspergillus glaucus culture and left in a closed room for the mold to grow.

As it grows, the mold is repeatedly shaved off until it ceases to take hold. The fish will become hard and dry as wood. Less than 20% of its original weight, it is known as called karebushi (枯節) or honkarebushi (本枯節).

Shaving

Katsuobushi kezuriki used to prepare Katsuobushi shavings

Traditionally, large chunks of katsuobushi were kept at hand and shaved when needed with an instrument called a katsuobushi kezuriki, similar to a wood plane.

Katsuobushi is today typically found in bags of small pink-brown shavings. Smaller, thinner shavings, called hanakatsuo (花鰹; はなかつお), are used as a flavoring and topping for many Japanese dishes, such as okonomiyaki. Larger, thicker shavings, called kezurikatsuo (削り鰹; けずりかつお), are used to make the ubiquitous dashi stock.

Uses

In addition to making dashi, other popular uses of katsuobushi include:

• Okaka (おかか), finely chopped katsuobushi dressed with soy sauce.
  • As a stuffing for rice balls (onigiri).
  • As a topping for rice. Popular for bentō, often covered with nori.
  • Dried okaka is used as an ingredient of furikake rice topping (called "okaka furikake").
• As a seasoning for cold tofu (hiyayakko, 冷奴) along with grated ginger and Welsh onion (a type of spring onion.)
• Sprinkled with sesame seeds and chopped nori atop cold soba noodles (zarusoba).
• As a topping on takoyaki and okonomiyaki.
• As a seasoning on century egg along with sesame oil and soy sauce.
• As a high-protein treat for cats sold at pet stores.

External links

• Video of dancing fish flakes
• an interesting description of katsuobushi seen in the Tsukiji fish market
• Production images of katsuobushi