Moist-heat methods cook food in water, stock or steam. The temperature of the liquid matters more than any other thing.
Key idea
Poach: about 160°F to 180°F; the liquid barely moves (eggs, fish, fruit). Simmer: about 185°F to 205°F; small bubbles break gently (stocks, stews, beans). Boil: 212°F at sea level; large, rolling bubbles (pasta, blanching green vegetables). Steam: food above boiling water in a closed space; it keeps shape, color and nutrients well.
| Height above sea level | Water boils at about |
|---|---|
| Sea level | 212°F |
| 2,500 ft | 207°F |
| 5,000 ft | 203°F |
| 7,500 ft | 198°F |
| 10,000 ft | 194°F |
Why it works
Air pressure is lower in the mountains, so water boils at a lower temperature, and food in boiling water cooks more slowly. Pasta and beans take longer in Denver than in Miami, and candy recipes need adjusting.
Worked example: Mountain boil
About what temperature does water boil at 6,000 feet?
- About 1°F less per 500 ft: $6000 \div 500 = 12$.
- $212 - 12 = 200$.
Answer: About 200°F.
Common mistake
Boiling food that should be poached. A rolling boil toughens fish and chicken and breaks up eggs. Turn the heat down until the liquid barely moves.
Practice at home
- Heat a pot of water with a thermometer in it. Note what the surface looks like at 170°F, 190°F and 212°F, so you can judge without the thermometer later.
- Poach an egg in water at about 180°F, and another at a hard boil. Compare.
The science behind it
- Freezing point depression and boiling point elevation: what salt does (and doesn't do) to boiling water
- Heating curves and phase changes: why water stays at 212°F while it boils