Fish skin not crisp

Skin contracts faster than flesh

Fish skin is a thin layer of collagen and it shrinks quickly and violently when it hits heat. The flesh underneath does not shrink at the same rate.

The result is that a fillet laid skin down in a hot pan immediately domes upwards in the middle, so only the edges are touching the pan. The middle of the skin never gets hot enough to crisp, and it steams instead.

Fifteen seconds of pressure with a spatula while the collagen sets is all it takes. After that the fillet stays flat on its own.

Getting it crisp

1. Dry the skin thoroughly with kitchen paper. Then dry it again just before it goes in.
2. Score the skin lightly two or three times if the fillet is thick, cutting through the skin but not into the flesh. This lets it contract without doming.
3. Salt the skin just before cooking, not several minutes before.
4. Get the pan properly hot with a thin film of oil.
5. Lay the fillet skin down away from you, and immediately press it flat with a fish slice or a spatula for ten to fifteen seconds.
6. Then leave it alone. Do not move it, lift it, or check underneath.
7. Cook most of the way through on the skin side — around three quarters of the total time — then turn it for a minute to finish.
8. Serve skin side up. Skin resting on a plate softens within a minute.

Which fish crisp well

Sea bass, bream, mackerel, salmon

Excellent. Thin firm skin with enough fat under it.

Red mullet, snapper, trout

Very good.

Cod and haddock

Delicate skin that tears easily. Possible with care, and often better skinless.

Plaice and sole

Thin and fragile. Usually skinned, or floured and cooked gently.

Skin-on fillets bought pre-scaled

Check. A stray scale ruins the mouthful, and scaling after cooking is impossible.

Frozen fish

Releases a great deal of water. Thaw fully and dry very thoroughly.

What goes wrong late

• Served skin down on a plate, so it sits in its own steam. Serve skin up, always.
• Sauce poured over it. Serve the sauce alongside or underneath.
• Rested under foil, which softens it in seconds.
• Turned too early, before the skin has set and released.
• A pan that was not hot enough, so the skin stuck and tore when moved.
• Crowded pan, dropping the temperature and steaming everything.

The pan, the fat and the heat

Three equipment decisions decide as much as technique does.

The pan

Heavy-based stainless steel or cast iron. Non-stick cannot get hot enough and gives a paler, softer skin.

The heat

Medium-high and steady. High enough to drive moisture off, not so high that the skin scorches before the flesh cooks.

The fat

A neutral oil with a high smoke point. Butter alone burns; add it at the end for flavour once the skin is set.

How much fat

Enough to film the pan generously. A dry pan gives uneven contact and patchy skin.

The fish press or spatula

Thirty seconds of gentle pressure as it goes in, to stop the skin contracting away from the pan.

The pan size

Big enough that the fillets are not touching. Two fillets in a crowded pan steam each other.

Common questions