Cooking regime

Wet heat at or below boiling

Boiling, simmering, poaching, blanching and steaming all share one thing: water at ordinary pressure cannot exceed its boiling point, so none of them can go above it. Everything that distinguishes them happens below that ceiling.

A ceiling, and what it costs

Liquid water cannot get hotter than its boiling point at ordinary pressure. Add more heat and it simply boils faster, converting the extra energy into steam rather than into a higher temperature.

That ceiling is well below what browning needs, which is why nothing boiled, simmered, poached or steamed ever browns. Wet heat and a crust are mutually exclusive, and no amount of turning the hob up changes it.

What the ceiling buys instead is control and gentleness. It is very difficult to overheat something in water, the temperature is the same everywhere in the pan, and heat transfers fast enough to cook things through evenly.

The four temperaments

Boiling

Vigorous, agitated, fast. For pasta, green vegetables, potatoes and anything robust. The movement is as important as the heat.

Simmering

A few bubbles breaking. For stews, pulses, stocks and anything that would fall apart or cloud in a boil.

Poaching

Barely trembling, well below boiling. For eggs, fish and fruit — anything delicate enough that even a simmer would damage it.

Blanching

Very brief boiling, usually followed by ice water. To set colour, loosen skins, destroy enzymes or part-cook ahead.

Steaming

The food never touches the water. Nothing leaches out, so flavour and nutrients stay put.

Braising and stewing

Wet heat plus a lid, usually after browning. The crossover method.

What wet heat is good and bad at

• Good at even cooking. The temperature is identical throughout the pan, so nothing has a hot side.
• Good at gentleness. It is nearly impossible to burn something in water.
• Good at breaking down collagen in long slow cooking, which is what makes a braise tender.
• Good at hydrating — pasta, rice, pulses and grains all need water to cook at all.
• Bad at flavour development. No browning, so no Maillard compounds and none of the depth they bring.
• Bad at retaining soluble things. Flavour, colour and water-soluble nutrients leach into the liquid, which is why the cooking water of vegetables tastes of them.
• Bad at texture on the surface. Nothing wet-cooked is crisp.
• The remedy for all three is to keep the liquid and use it, or to brown before or after.

Choosing between them

1. Ask whether the food is delicate. If it would break up or toughen, go below a simmer.
2. Ask whether you want the liquid. If yes, simmer and keep it; if not, steam so nothing leaches out.
3. Ask whether you want agitation. Pasta and green vegetables want the movement of a boil; a stock and a stew want stillness.
4. Ask whether it needs to be fast. Blanching is fast and precise; braising is slow and forgiving.
5. Add salt to the water for anything that will absorb it, which is most things.
6. Cover for steaming and for anything you want to keep aromatic; uncover for anything you want to reduce.
7. Consider browning before or after, which is how you get both the tenderness and the flavour.
8. Whether a food is safely cooked is a matter for a food safety authority rather than for a description of how the heat arrives. In the UK the Food Standards Agency sets that guidance and it is the one to follow.

Common questions