Cooking method

Steaming

Steaming cooks food in water vapour rather than in water. Nothing leaches out, nothing knocks the food about, and the temperature is capped at 100°C — which makes it the gentlest way to cook something through without changing what it tastes of.

Why it is not just weaker boiling

Both cap out at 100°C, and the differences are all about contact. In boiling water, soluble compounds diffuse out of the food into the liquid — sugar, salt, water-soluble vitamins, flavour. In steam there is nowhere for them to go, so they stay put. A steamed carrot tastes noticeably more of carrot than a boiled one.

Steam also touches the food gently rather than churning against it, so nothing breaks up. That makes it the right method for fish, dumplings, custards and anything fragile.

And steam carries more energy than water at the same temperature. When it condenses on cold food it releases a large amount of heat at once, which is why steaming is faster than people expect — and why a steam burn is far worse than a splash of boiling water.

What steaming suits

• Green vegetables, where you want the flavour to stay in the vegetable rather than in the water.
• Fish, which stays in one piece and cannot dry out.
• Dumplings, buns and anything with a wrapper, which would disintegrate in water.
• Custards and puddings, cooked in a covered bowl over water — a gentler, more even heat than an oven.
• Reheating rice and leftovers, which steam restores far better than a microwave.
• New potatoes and root vegetables, which come out drier than boiled and take dressing better.
• Not for anything you want browned, which steam can never do.

Steaming without a steamer

1. A colander or a metal sieve over a pan of simmering water, with a lid or a plate on top. The commonest improvised version and it works.
2. A heatproof plate resting on a ball of scrunched foil or an upturned ramekin in a wide covered pan.
3. A bamboo steamer over a wok, which is the traditional version and stacks so you can cook several things at once. The bamboo lid absorbs condensation rather than dripping it back.
4. A little water in a lidded frying pan with the food on a rack — effectively a shallow steamer.
5. In every case: the water must not touch the food, the lid must fit reasonably, and the water must be simmering before the food goes in.

Doing it well

• Do not let the water touch the food. That is boiling, not steaming.
• Keep the lid on. Every look lets the steam out and stops the cooking.
• Do not overcrowd. Steam has to circulate, exactly as hot air does in an oven.
• Season the food, not the water. Nothing diffuses in from the water, so salt goes on the food itself.
• Flavour the steam if you like — ginger, lemongrass, herbs, citrus peel, wine in the water. It is a modest effect and a pleasant one.
• Check earlier than you think. Steaming is faster than boiling for many things.
• Take the lid off away from you, and never reach over an open steamer.

Common questions