Katsuo – bonito

The bonito, skipjack tuna or katsuo in Japanese, has an unfortunate name. In fact, it is not a tuna but a fish from the mackerel family. Because the fish is so versatile, it has a true hero status in Japan. The bonito is actually a swimming stock cube. There is hardly a dish in Japanese cuisine that does not include this condiment. Broth from the katsuo, dashi, is the base of almost every Japanese dish. Smoked and shaved, we know the fish as katsuo bushi. When you put katsuo bushi shavings on a hot dish, it immediately comes alive. Due to the extremely light weight of the shavings, you will see that they begin to dance in the vapor of the dish. A magical sight and very instagrammable, which has also earned the fish hero status online.

In Shiogama, near Sendai, I learned that katsuo has many other variations. The company Meiho is a major bonito producer. Bonito, like tuna, is always frozen at extremely low temperatures, otherwise the meat discolors and the shelf life is much shorter. So during my visit to the company we were given a tour around a freezing cell that noted as much as -60 degrees. With iciles hanging from our noses and eyes half squeezed shut, we walked past crates full of frozen beautiful whole katsuo. The fish are caught with a hook and rod. They bite down on everything so you don’t even need bait on your hook, the director of Meiho told us in the cold. On board, a number of fisherman men stand ready with rods and when they sail over a shoal of katsuo it is simply a matter of hooking the fish and with a powerful bow swishing the bonito over your own head into the hold behind you. The fish is then immediately, frozen whole and stored at minus 60. Processing takes place without thawing the fish first. Large band saws are used to cut the fillets from fish. Then the frozen intestines are brushed out, as it were, with a special device that reminded me of a polishing machine from the local chop shop. After this, the still stiffly frozen fillets pass through a blazing inferno of gas torches, which cook the outside of the fillet. This process is called tataki. The inside remains raw and is still frozen. If you thaw the katsuo tataki at home and slice it into nice thin slices, there is a wonderful contrast in both taste and appearance between the charred outside and the silky, red and raw inside. This is incredibly delicious with a dressing of soy sauce (from Hokkai ;), spring onion, and ginger.

We received a large shipment of these roasted fillets and, of course, stored them neatly, as they would in Japan, at sixty degrees below zero. In an average kitchen freezer that cools to about minus eighteen degrees, you can keep this fish good for only four weeks. So cut it up quickly!