Ingredient

Mackerel

Mackerel is one of the best-value fish there is and the one where freshness matters most. Its high oil content is what makes it delicious and what makes it deteriorate faster than almost any other fish.

Why freshness matters more here

Oily fish carry their fat throughout the flesh rather than concentrated in the liver. Those oils oxidise on contact with air, and oxidised fish oil is what "fishy" actually means — a fresh fish smells of the sea and almost nothing else.

Mackerel is at the extreme end of this. A mackerel a day old is excellent; one four days old is noticeably strong; one a week old is unpleasant. This is why mackerel has a reputation for being strong-tasting, and it is largely a reputation earned by fish that was not fresh.

It is also why so much mackerel is smoked, salted or tinned. Those are all ways of dealing with a fish that does not keep.

The practical rule follows directly: buy mackerel on the day you intend to cook it, buy it from somewhere that sells enough to turn its stock over, and cook it that evening rather than the next. Of all the common fish it is the one where a day makes a visible and tasteable difference, and it is the reason mackerel is both one of the cheapest fish on the counter and one of the best things you can eat.

Telling a fresh one

• Bright, clear, domed eyes. Sunken cloudy eyes mean an old fish.
• Vivid, iridescent skin markings. Mackerel fades quickly and a dull one is old.
• Firm flesh that springs back when pressed.
• Bright red gills, not brown.
• It should smell of clean sea water and nothing else. Any real fishiness means walk away.
• Stiff rather than floppy when held.

How to cook it

Grilled or barbecued whole

Scored, oiled, salted, over a fierce heat. The classic and probably the best.

Pan-fried fillets

Skin-side down in a hot pan, pressed flat, until the skin is crisp — about three-quarters of the cooking. Then thirty seconds on the flesh.

Roasted

Whole with lemon and herbs in the cavity, 200°C for fifteen to twenty minutes.

Soused or pickled

In spiced vinegar. Traditional and excellent.

Smoked

Widely available ready-smoked. Good in a pâté with cream cheese, lemon and horseradish.

Not for

Gentle poaching in a delicate broth, where its oiliness overwhelms everything.

What it needs alongside

• Acid, always. Lemon, vinegar, gooseberry, rhubarb, pickled things. The oiliness demands it.
• Horseradish and mustard, which cut through in the same way.
• Sharp leaves — watercress, rocket — and beetroot.
• Potatoes, which are the traditional foil.
• Strong spicing works well: cumin, coriander, chilli, harissa.
• Not cream, not butter sauces, and not anything rich. It is rich already.

Smoked, tinned and soused

A fish that spoils fast has a long history of being preserved, and the preserved forms are not second best.

• Hot-smoked mackerel. Cooked and smoked, sold as fillets. Flake into a pâté with crème fraîche, horseradish and lemon, or into a salad with beetroot.
• Tinned mackerel, in oil or in tomato. Excellent on toast, in a rice bowl, or mashed with mustard and onion.
• Soused mackerel. Fillets cooked and steeped in spiced vinegar. A British preparation worth reviving, and it keeps for days.
• Salted and dried, in various cuisines, and rehydrated before use.
• All of them are strongly flavoured, so they want acid and something starchy: potato, bread, rice, or a sharp salad.
• Horseradish, mustard, gooseberry and rhubarb are the classic partners, and all four work for the same reason.
• The preserved forms keep the oiliness, which is why they satisfy in a way tinned white fish does not.

Common questions