Katsuo no Tataki (Bonito Seared over a Straw Fire)

Name: Katsuo no Tataki (Bonito Seared over a Straw Fire)
Prep time: 30 min
Cook time: 10 min
Total time: 40 min
Yield: 4 servings
Cuisine: Japanese
Ingredients: 400 g bonito fillet, skin on; 1 armful rice straw; 3 cloves garlic; 4 spring onions; 0.5 onion; 1 knob ginger; 6 shiso leaves; 2 myoga; 100 ml ponzu

A Kochi dish of skin-on bonito seared fast over a straw fire on the surface only, then sliced thick and covered with garlic, spring onion and ponzu. The outside smells almost smoked; the inside is still sashimi.

Ingredients

4servings

bonito fillet, skin on · previously frozen at −20°C for at least 7 days400 g
rice straw · see Variations if you have none1 armful
Condiments
garlic · thinly sliced3 cloves
spring onions · finely sliced4
onion · thinly sliced, kept in water0.5
ginger · grated1 knob
shiso leaves6
myoga · optional, shredded2
ponzu100 ml

Steps

Use bonito that has been frozen at −20°C for at least 7 days, thawed in the fridge. Pat it dry.
Lay it skin side down and push three or four metal skewers through it in a fan.
Outdoors, light the straw in a metal tub or brazier. When the flames leap up, hold the skin side in them first.
⏲ 1 min
Turn it to sear the other faces on the surface only, just until they go pale. The inside is not cooked.
⏲ 40 sec
Twist out the skewers. Do not plunge it into ice water; let it cool for a few minutes as it is, then chill it in the fridge.
⏲ 5 min
Slice it 1cm thick and lay the slices out on a platter.
Scatter over the garlic, spring onion, drained onion, ginger and myoga and pour on the ponzu. Pat lightly with your fingertips so it all sticks.
Rest in the fridge for about an hour and serve with the shiso. Eat it the same day.
⏲ 60 min

Variations

Shio tataki. Rub the fillet with a generous amount of coarse salt before searing, then slice it while still hot and serve with the condiments.
Salt and yuzu only. Some people eat it with no soy or vinegar at all, just salt and yuzu juice.
Without straw. Sear the surface over a gas flame, with a blowtorch or in a very hot dry pan. You lose the straw smoke.
Yakigiri. In Shishikui, over the border in Tokushima, several kinds of fish are seared the same way, with yuzu vinegar and salt patted in by hand and sliced onion on top.
Tosa-maki. A sushi roll with katsuo no tataki inside.

Tips

Because of parasites, use only bonito that has been frozen. A fire that sears the outside never reaches the inside.
Sear the surface only. The middle stays sashimi.
No ice water. It washes out the straw aroma.
Slice it thick, about 1cm. Every piece keeps a band of seared edge.
Pat the condiments on by hand. One explanation of the name tataki ("pounding") is this step.
Seared or not, it is raw fish. Among the origin stories Japanese Wikipedia gives are a lord who banned raw bonito for fear of food poisoning, so people seared the outside and called it grilled fish, and a claim that searing was meant to kill parasites under the skin. The fire only cooks the surface, though. As with the acid in ceviche, treating the outside does not make the inside safe, so use fish frozen at −20°C for 7 days, the standard poke gives (freezing and thawing).

More detail and the reasons why (1)

A straw fire is used because it is short. Ca loc nuong trui also cooks fish over burning straw, but there the fish is cooked right through under its scales and the burnt scales are thrown away. Katsuo no tataki uses the same fire the other way round. Straw burns hot and is gone fast, so it chars the outside without reaching the middle, and here the outside is the part you eat. Japanese Wikipedia lists what the searing gives: an aroma close to smoking, a drier surface that firms the texture and concentrates the taste, and heat reaching the thin layer of fat between skin and flesh so it becomes good to eat. Straw is chosen for the season and for its smell. For handling a charcoal fire, see grilling.