Katsuobushi Grading Honkarebushi Arabushi

Japan (Makurazaki Kagoshima, Yaizu Shizuoka, and Tosa Kochi as primary production regions; technique developed from 17th century)

Katsuobushi (鰹節) — dried fermented bonito — exists on a quality spectrum defined by the number of mould cultivation cycles it has undergone. Arabushi (荒節) is the basic form: the bonito has been filleted, steamed, smoked, and sun-dried but has received no mould cultivation. It has a direct, robust, slightly smoky flavour and is the standard grade used in commercial dashi production and household dashi bags. Karebushi (枯節) has undergone at least one mould cultivation cycle: Aspergillus glaucus is applied to the surface of the dried fish, which grows across the block over 2–3 weeks, drawing out residual moisture and enzymatically breaking down proteins into amino acids. After the mould is brushed off, the process is repeated. Honkarebushi (本枯節, 'truly dried node') has undergone three or more mould cycles and has been aged for 6 months to 2 years. The result is an extraordinarily hard, dense block — like wood or stone — with a complex, deeply layered flavour profile. When shaved, honkarebushi produces translucent flakes with a refined, complex aroma and the highest inosinic acid concentration, producing the most nuanced and prized ichiban dashi.

Arabushi: smoky, direct, robust; honkarebushi: complex, layered, refined, deeply marine with no harsh smoke; the finest produces exceptionally clear nuanced dashi