Water & Steam

Boil

Cook in vigorously bubbling liquid at full rolling heat

Boiling cooks food in water or stock kept at a hard, rolling churn. It's the right call for pasta, blanching greens, and starchy vegetables that need fast, even heat. Salt the water generously and keep the bubbles lively so everything cooks uniformly.

Boiling cooks food in water or stock kept at a full, rolling churn — bubbles breaking hard and continuously across the whole surface, holding at 100°C / 212°F at sea level. It delivers fast, vigorous, even heat, which makes it the right call for pasta, blanching greens, hard-boiled eggs, and dense starchy vegetables that need to cook through quickly. The motion of a hard boil keeps food moving so it cooks uniformly, but that same agitation can batter delicate items, which is why gentler relatives — simmering and poaching — exist for anything fragile.

Difficulty: Easy

Types & varieties

Rolling boil

Full, vigorous churn for pasta and blanching.

Parboil

Partial boil to pre-cook food that finishes by another method (e.g., roasting potatoes).

Reducing boil

Hard boil to drive off water and concentrate a liquid or sauce fast.

How to do it

1
Use enough water
Fill a large pot so food has room to move and the temperature won't crash when it goes in.
2
Salt the water well
For pasta and vegetables, salt generously — it seasons from within and barely affects boiling point.
3
Bring to a full boil
Cover to reach a rolling boil faster, then uncover (covered pasta water can foam over).
4
Add food, keep it rolling
Add in amounts that keep the boil going; stir at the start so pasta or dumplings don't clump or stick.
5
Cook to the right point
Test early and often — pasta to al dente, potatoes to a knife sliding in with slight resistance.
6
Drain promptly
Drain at once (save a little pasta water for sauce); residual heat keeps cooking.

Altitude and salt

Water boils at 100°C / 212°F at sea level, but the boiling point drops roughly 1°C for every ~300 m of elevation (about 1°F per 500 ft) — at high altitude water boils cooler, so foods take longer to cook. Salt raises the boiling point only trivially (a teaspoon in a pot changes it a fraction of a degree), so salting water is about seasoning the food, not making it boil hotter. The vigorous bubbles of a boil aren't hotter than a simmer's — both cap at the boiling point — they just transfer heat faster through agitation.

Common uses

Pasta and noodlesPotatoes for mashingHard- and soft-boiled eggsCorn on the cobBlanching green vegetablesGrains and legumesLobster and crab

Tips & pitfalls

Don't add oil to pasta water; it coats the noodles and keeps sauce from clinging.
Salt water until it tastes like the sea for pasta and green vegetables.
Reserve a cup of starchy pasta water — it emulsifies and loosens sauces.
Drop a lid on to reach the boil faster, then remove it to prevent boil-overs.