Ingredient

Tuna

Tinned tuna and a fresh tuna steak have almost nothing in common in the kitchen. One is a cooked, flaked, store-cupboard protein; the other is dense red muscle that behaves more like beef than like fish — and that comparison is the most useful thing to know about cooking it.

Why fresh tuna dries out

Most white fish is pale because it is made of muscle used in short bursts. Tuna are fast, constantly swimming, warm-blooded ocean fish, and their muscle is dark red with a great deal of myoglobin — closer in structure to a beef steak than to a cod fillet.

That has one dominant practical consequence: tuna has very little fat and very little connective tissue in the loin, so when its proteins contract and squeeze out water there is nothing left to keep it moist. Overcooked tuna is dry, grey, chalky and slightly livery, and there is no slow-cooking window to rescue it as there is with squid or brisket.

So a tuna steak is cooked like a rare beef steak: a very hot pan, a very short time, a deeply browned crust and a red centre. A minute or so a side on a thick steak. The moment the colour has travelled all the way through, the texture has gone.

Whether tuna should be served rare, and for whom, is a food safety question rather than a culinary one. FoodHQ does not publish safe cooking temperatures or keeping times. Those are set by a food safety authority rather than by a cookery writer, and in the UK the Food Standards Agency is the one to consult.

Reading a tin

The differences between tins are larger than people assume.

In oil

Richer, moister, and far better for salads, pasta and anything eaten as it is. Good olive-oil tuna is a genuinely different product from the standard tin. Use the oil.

In brine

Leaner, saltier, drier. Fine in a sandwich or a bake where something else is providing moisture.

In spring water

The blandest. Drains to something quite dry.

Chunk against flakes

Chunk is larger, firmer pieces. Flakes are smaller fragments and cheaper. Solid or "ventresca" — belly — is the best and most expensive.

Species

Skipjack is the commonest and lightest. Yellowfin is firmer and more expensive. Albacore or "white tuna" is pale and mild.

Sourcing

Fishing method and stock status vary enormously and change year to year. Pole-and-line and FAD-free labels indicate lower bycatch. Check a current rating rather than relying on a fixed rule.

What to do with each

• Fresh — seared hard and sliced, with soy, sesame, ginger and chilli, or with a salsa verde.
• Fresh — grilled or barbecued, briefly, marinated first.
• Fresh — raw, as sashimi, tartare or crudo, where sourcing is everything and is a question for your fishmonger and for the Food Standards Agency.
• Fresh — in a niçoise, seared and sliced rather than tinned, which is the older version of the dish.
• Tinned — in a pasta sauce, with garlic, chilli, capers, olives and tomato. One of the great cheap dinners.
• Tinned — in a salad, with beans, red onion and a sharp dressing.
• Tinned — vitello tonnato style, blended with capers, anchovy and mayonnaise into a sauce.
• Tinned — in a fishcake or a bake, where its dryness is compensated by everything around it.
• Do not cook tinned tuna hard. It is already cooked, and reheating it aggressively makes it dry and strong-tasting.

Searing a tuna steak

Treat it exactly as you would a rare beef steak, and be quicker than feels comfortable.

1. Take it out of the fridge twenty minutes beforehand, so the centre is not fridge-cold when the outside is searing.
2. Pat it completely dry and season it well. A wet surface will not crust.
3. Roll the edges in crushed black pepper or sesame seeds if you want a crust — both are traditional and both add texture the fish itself lacks.
4. Get a heavy pan as hot as you dare, with a little oil that can take the heat.
5. Lay the steak down and leave it. Sixty to ninety seconds for a thick steak, without moving it.
6. Turn once and give the other side the same. Sear the edges briefly by holding it on its side with tongs.
7. Take it out while the centre is still clearly red, rest it for a minute or two, and slice it across the grain into thick slices.

Common questions