Getting the Skin Crisp

Crisp chicken skin is not difficult, but almost everything people do to chase it addresses the wrong stage. Turning the oven higher, basting more, adding oil — none of these help if the problem is moisture, and the problem is almost always moisture.

Water first, everything else second

While there is liquid water on a surface, that surface cannot exceed 100 °C. All the energy going into it is spent turning water into steam rather than raising the temperature. Browning reactions do not begin in earnest until around 140 °C, which means a wet chicken skin in a hot oven is not browning at all — it is being steamed, and it will carry on being steamed until the water has gone.

On a bird straight from the packet that can easily take twenty minutes. Twenty minutes in which the meat underneath is cooking and the clock is running, and at the end of it the skin is only just starting to do what you wanted.

The fix costs nothing and happens the day before: salt the bird and leave it uncovered in the fridge. Refrigerator air is dry and constantly moving, and twelve hours of it removes far more surface moisture than any amount of patting with kitchen paper.

Then the fat has to get out

Chicken skin sits on a layer of subcutaneous fat. If that fat is still there at the end of cooking, the skin will be soft and slightly greasy no matter how brown it looks — this is the flabby-but-coloured result that comes out of a very hot, very fast oven.

Rendering needs time at a moderate temperature more than it needs extreme heat. This is the argument for starting a bird hot, dropping the temperature for the long middle stretch, and finishing hot again if it needs colour: the middle stretch is when the fat leaves.

It is also the argument for a rack. Skin sitting in a pool of its own rendered fat is being confit-ed rather than roasted, and confit skin is many things but crisp is not one of them.

Practical rules

• Never cover it. Foil traps steam against the surface and undoes the whole thing in five minutes.
• Never baste it. Basting spoons liquid onto a surface you have spent an hour drying. It does not keep the meat moist — the skin is a barrier and the liquid never gets past it.
• Keep liquid below the skin line. In any braise or tray bake, stock goes under the chicken and never over it.
• Give each piece space. Pieces packed together humidify each other. Two trays beat one crowded one.
• Use a rack where you can. Air underneath means the base crisps too, instead of sitting in fat.
• Salt at the end as well. A final pinch on skin straight out of the oven is the difference between good and very good, and it costs nothing.

The baking powder trick

A small amount of baking powder mixed with the salt — around a quarter of the salt's weight — raises the pH of the skin surface. Browning reactions run faster in alkaline conditions, and the carbon dioxide released creates fine bubbles that give the skin a blistered rather than smooth texture, with more surface area and a better bite.

It must be baking powder, not bicarbonate of soda. Bicarbonate alone is strongly alkaline and leaves a distinct soapy, metallic taste. This is the one place in chicken cookery where a chemical shortcut genuinely earns its place, and it is why the wings recipe uses it.