Why Does It Take Longer to Boil an Egg at High Altitudes?
If you have ever camped on a high mountain, you probably discovered that it takes longer to cook your food up there. At higher altitudes, the atmospheric pressure is lower, and, though it takes less heat to make water boil, it takes longer to create the heat.
Cooking is difficult at high altitudes because water cannot get hot enough to cook food properly. At 10,000 feet above sea level, the water boils at only 194 degrees F. (At sea level, water boils at 212 degrees F.) But it takes 8 to 10 minutes to hard-boil an egg because of low air pressure at this lofty height.
As altitude increases and atmospheric pressure decreases, the boiling point of water decreases. To compensate for the lower boiling point of water, the cooking time must be increased. Turning up the heat will not help cook food faster. No matter how high the cooking temperature, water cannot exceed its own boiling point — unless if using a pressure cooker. Even if the heat is turned up, the water will simply boil away faster and whatever you are cooking will dry out faster.
It can take longer to cook eggs at high altitudes, especially those cooked in boiling water such as poached and hard-cooked eggs. Because water boils at a lower temperature at high altitudes, hard-cooked eggs will take longer to prepare. It will most likely take longer to hard cook eggs at high altitudes than at sea level.
Many cooking methods can be used to cook eggs safely at high altitudes including poaching, hard cooking, scrambling, frying and baking. In general, do not increase the heat, just increase the cooking time. Eggs must be cooked thoroughly until yolks are firm.