The boiling temperature of water changes with altitude, which means that egg whites and yolks will not be fully cooked if boiled on the 8,849-meter high peak of Mount Everest. Eggs can be soft-boiled or hard-cooked almost anywhere in the world, but not at the highest point on Earth above sea level. This thermodynamic phenomenon has implications for food and drink preparation globally.
The issue on Mount Everest is related to air pressure, which affects the boiling point of water. At sea level, water boils at 100 degrees Celsius, but as altitude increases, the boiling point decreases. For every 300 meters increase in altitude, the boiling temperature drops by one degree Celsius. The town of La Rinconada in the Andes is the world’s highest permanently inhabited place, where water boils at 82.8 degrees Celsius.
At the summit of Mount Everest, the pressure is about 1/3 of atmospheric pressure, causing the boiling temperature of water to drop to 68 degrees Celsius. Although this is hot enough to cause burns, it is not sufficient to completely boil an egg. The proteins in egg whites and yolks coagulate at different temperatures, with the egg white needing 80 degrees Celsius and the yolk needing 70 degrees Celsius to firm up.
If you are at the peak of Mount Everest and want to cook boiled eggs, the only solution is to use a pressure cooker to increase the boiling point through elevated pressure inside the pot. This unique cooking method becomes necessary at extreme altitudes to achieve a fully cooked egg.