Cooking method

Roasting

Roasting is cooking in the dry, circulating heat of an oven. What makes it different from every other method is that the surface can get far hotter than boiling point, so it dries, browns and develops a crust while the inside cooks gently.

What the oven is actually doing

Three things carry heat to food in an oven: hot air moving around it, radiant heat from the walls and elements, and conduction from the tin it sits on. All three are dry, which is the point — no water is being added, so the surface can rise well above 100°C once its own moisture has evaporated.

That is what separates roasting from boiling, steaming or braising. Those methods cap the surface at the boiling point of water and so can never brown. Roasting is the household method that produces the deepest browning on the largest pieces of food.

It also means the same failure recurs everywhere: surface moisture stops it working. A wet surface, a crowded tin or a covered dish all keep the food at 100°C, and what you get is oven-steamed food that looks pale and tastes of very little.

Choosing a temperature

The single decision that shapes the result, and it is a trade between crust and evenness.

High, 200–230°C

Maximum browning, fastest cooking, least even. Right for vegetables, potatoes, small pieces, and anything you want crisp.

Moderate, 180–200°C

The everyday setting. Enough browning, reasonably even. Most whole birds and joints.

Low, 140–160°C

Very even, gentle, and much better at not drying the outer layers. Large joints, and anything you will brown separately.

Very low, 100–130°C

The slow-roast range. Excellent for shoulder cuts and for a reverse sear, where a hot blast comes at the end.

Two-stage

A blast of high heat at the start or the end, and moderate or low for the rest. This gets the crust and the evenness together, and is what most good roasting recipes are doing.

Fan

Moves air faster, so it dries and browns better and cooks quicker. The convention is to set it around 20°C below a conventional recipe.

The rules that decide the outcome

• Space in the tin. Everything must have air around it. A crowded tin steams; two tins is almost always better than one.
• A dry surface. Pat meat dry, steam potatoes dry, and salt in advance so moisture is drawn out and reabsorbed.
• Preheat properly, including the tin and the fat if you are roasting potatoes.
• Use a rack for a joint or a bird so heat reaches the underside, and no rack for vegetables, which want contact with hot metal.
• Do not cover it unless you are deliberately steaming — foil traps moisture and prevents everything roasting is for.
• Rest anything large. Heat keeps travelling inwards for a long time after it comes out.
• Sugar goes on late. Honey, maple and barbecue glazes burn long before the food is done.

Where roasting is the right choice

• Root vegetables, brassicas, squash, onions, peppers, aubergine — dry heat concentrates their sugars and browns them, which no wet method can.
• Whole birds and large joints, where you want a browned exterior and a gently cooked interior.
• Tender cuts, briefly and hot.
• Tough cuts, slowly — a low oven for many hours is a dry-heat cousin of braising, and it is how pulled pork and slow-roast shoulder work.
• Nuts, seeds, breadcrumbs and spices, which want gentle even heat rather than a pan.
• Not for lean, thin things — a chicken breast or a fish fillet dries out before it browns.

Common questions