The boiling point of water is lower at higher altitudes due to the decreased atmospheric pressure. High-altitude cooking requires a compensation for lower temperatures for any cooking that involves boiling or steaming. This effect starts to become relevant at altitudes above 2,000 feet (610 m). Means of compensation include boiling/steaming for longer times or using a pressure cooker to provide higher pressure inside the cooking vessel, and hence higher temperature.
Video High-altitude cooking
Boiling
At sea level water boils at 100°C. For each 500 ft (~150 m) increase in elevation, the boiling point is lowered by 0.5°C. For 8,000 ft (~2500 m) elevation, water boils at 92°C. Boiling as a cooking method must be adjusted or alternatives applied. Vegetables and some starches will simply take longer to cook while rice and legumes (beans) need a pressure cooker. Pasta will need a pressure cooker.
Maps High-altitude cooking
Methods used at high altitudes
From pressure cooking: A pressure cooker is often used to compensate for the low atmospheric pressure at a very high elevation. Under these circumstances water boils at temperatures significantly below 100°C (212°F) and, without the use of a pressure cooker, may leave boiled foods undercooked, as described in Charles Darwin's The Voyage of the Beagle:
"Having crossed the Peuquenes (Piuquenes), we descended into a mountainous country, intermediate between the two main ranges, and then took up our quarters for the night. We were now in the republic of Mendoza. The elevation was probably not under 11,000 feet [...]. At the place where we slept water necessarily boiled, from the diminished pressure of the atmosphere, at a lower temperature than it does in a less lofty country; the case being the converse of that of a Papin's digester. Hence the potatoes, after remaining for some hours in the boiling water, were nearly as hard as ever. The pot was left on the fire all night, and next morning it was boiled again, but yet the potatoes were not cooked."
Boiling point of pure water at elevated altitudes
Based on standard sea-level atmospheric pressure (courtesy, NOAA):
Source: NASA
References
External links
- Boiling point of water vs altitude
- Cooking at high altitudes
- Is it true that you can't make a decent cup of tea up a mountain? physics.org, accessed 2012-11-02
Source of the article : Wikipedia
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