10 Mind-Blowing Facts About the Science of Boiling an Egg Perfectly

2. Altitude Sabotages Your Timing (Lower Boiling Point Physics)

Cooking eggs at high altitude? Your usual timing will fail you. Why? Water boils when its vapor pressure equals the surrounding atmospheric pressure. Higher altitudes mean lower air pressure, so water boils at a lower temperature – roughly 1°C less for every 300 meters (1,000 ft) gained. Boiling water at 90°C (194°F) in Denver simply doesn't transfer heat as efficiently as 100°C (212°F) water at sea level. Result: you need significantly longer cooking times at altitude to achieve the same internal egg temperature and desired doneness.