Seared Ahi Tuna

Why This Seared Ahi Tuna Works

During the short marinating time, the soy sauce, lime juice, ginger, and garlic sit on the outside of the tuna and soak in just a little. The surface of the fish picks up salt and acid, so it seasons the outside well without cooking the inside. Sesame oil and olive oil coat the steaks, so they don’t stick and they brown faster once they hit the hot pan.

Once the tuna is pressed into the sesame seeds, the seeds form a thin crust. In the hot skillet, those seeds toast very quickly. They change from pale to lightly golden, and that toasted layer protects the outside of the fish from drying out. At the same time, the high heat sears only the outer edge of the tuna in a minute or two, while the center stays rare and soft.

After searing, slicing the tuna across the grain keeps each piece tender. The green onions go on at the end, staying crisp and fresh against the warm, just-cooked edges of the fish.

Mistakes To Avoid

Letting the tuna sit in the pan too long turns the center from rare to fully cooked. The flesh goes from soft and silky to firm and a bit chalky, and the outside can start to dry out instead of staying moist under the seared crust.

Starting with a pan that isn’t properly hot causes the sesame seeds to soak up oil and the tuna to slowly steam. Instead of a quick crust on the outside and a cool center, the steaks warm all the way through and the coating can taste greasy and pale.

Pressing on the tuna or moving it around a lot while it sears makes the sesame seed crust fall off. The seeds end up burning in the pan while the fish surface is left patchy and unevenly browned.

Marinating the tuna much longer than the 20 minutes lets the soy and lime pull moisture from the surface. The outside of the fish tightens up, so it can turn stiff and slightly tough once it hits the hot pan.