The process involved in the making of Katsuobushi
Katsuobushi is made from shipjack tuna. They are caught in equatorial regions in the Pacific Ocean and Indian Ocean.
Skipjack tuna are migratory fish that prefer warm regions. They can swim at speeds of up to 100 km/h. They are caught using round-haul nets or fishing lines. To preserve freshness, they are immediately frozen on the ship. After the fish are transported, workers quickly classify and separate them by type and size.
This takes about two days. Next, the frozen fish are thawed in warm water overnight to get them ready for processing.
Cutting & preparing the thawed fish (Namagiri)
The thawed fish’s head is cut off, and the interior is taken out. This process is greatly streamlined by many workers. The prepared fish is expertly arranged in metal basket containers. This procedure is known as Kagodate.
Shimmering the fish in hot water (Shajuku)
The fish containers are then dropped into a hot bath of water that is over 90C. After two hours of boiling, the fish’s meat is firm. Due to the possibility of fish harm from air bubbles in boiling water, temperature is particularly crucial.
Removing bones by hand (Hone-nuki)
The pace at which the workers’ hands move is astounding. Workers pick up every bone by hand after the fish has cooled using tweezers. The Katsuobushi will become cracked if the bones are not carefully removed. To manufacture well-shaped Katsuobushi, this procedure is crucial. Machines are incapable of accomplishing this. The fish are then ready to be smoked and dried.
Smoking and drying the fish with firewood
Using firewood, the fish are smoke-dried. This gives Katsuobushi its distinctive scent. When smoking fish, mostly oak wood is used. The smoke helps to preserve the fish in addition to producing a mouthwatering scent.
Arabushi is made by periodically smoking the fish and allowing it to cool for roughly twenty days.
A katsuobushi with a powerful smoky scent is called Arabushi. The entire process lasts around one month.
Scraping away the exterior (Polish)
Next mold will be added in to create Katsuobushi called Karebushi. The exterior has been heavily smoked, making it difficult for mold to grow there. To encourage the growth of the mold, the exterior is scraped and polished.
The Katsuobushi’s mild flavor and preservation are enhanced by the mold process. The air in the room is kept at 30°C and 90% relative humidity during the mold-growing procedure. To produce Karebushi, the molding procedure is repeated twice.
If the molding process is repeated further, it becomes the Katsuobushi called Hon-karebushi. This can take up to six months.
Slicing the dried fish into flakes.
It’s finally time to chop the katsuobushi into flakes. Shapes and scents are thoroughly examined before slicing. Each use calls for a different slice’s size and thickness. To maintain its flavor after slicing, the Katsuobushi is immediately packaged.