Ingredient

Mashed potato

Gluey mash is the result of broken potato cells releasing free starch, and it is caused by over-working. Everything about good mash is about breaking the potato down as gently as possible while getting fat into it.

Why it goes gluey

A cooked potato is a mass of cells packed with swollen starch granules. Handled gently, those cells separate from one another and stay intact, giving a light, fluffy mash. Worked hard — beaten, whisked, or put through a food processor — the cells rupture and release their starch into the liquid, which turns the whole thing into an elastic, gluey paste.

That change is irreversible. There is no way to un-glue mash, which is why the rule is to stop early rather than to fix it later.

A ricer or a mouli separates cells without tearing them and is the right tool. A masher works with a light hand. A hand whisk is risky. A food processor is guaranteed failure.

The method

1. Use floury potatoes — Maris Piper, King Edward, Russet. Waxy ones will not go fluffy.
2. Cut them into even pieces and start them in cold, well-salted water, so the outsides do not disintegrate before the middles cook.
3. Simmer rather than boil hard, until a knife goes in with no resistance at all. Undercooked potato gives lumps that cannot be mashed out.
4. Drain thoroughly and return them to the hot dry pan for a minute to steam off surface water. Wet mash is dilute mash.
5. Rice or mash them while hot. Cold potato is much harder to work without over-working.
6. Beat in butter first, off the heat, before any liquid. Fat coating the starch is what keeps it from going gluey when the milk goes in.
7. Then add warm milk or cream gradually, to the consistency you want, and season heavily. Mash needs a surprising amount of salt.

How rich do you want it

Everyday mash

Around 50g butter and a splash of milk per kilo. Light and fluffy.

Good mash

100g butter and warm milk or cream. Noticeably better.

Restaurant purée

Equal weights of butter and potato, passed through a fine sieve. Extraordinary, and not really a vegetable any more.

Champ or colcannon

Spring onions or cabbage and plenty of butter. The Irish answers, and both excellent.

Olive oil mash

Works well with a little garlic, and pairs better with fish than butter does.

Problems

• Gluey — over-worked. Not fixable. Next time use a ricer and stop sooner.
• Lumpy — undercooked potato. Cook them properly soft.
• Watery — not drained and dried enough, or waxy potatoes, or too much milk.
• Cold by the time it is served — warm the milk, warm the bowl, and hold the mash over a pan of hot water rather than reheating it.
• Grey — a reaction between compounds in the potato and iron. Harmless. A little acid in the cooking water reduces it.
• Bland — salt. Then more salt. And white pepper.

Common questions