🔬 The Science of Boiling Eggs
Learn why altitude affects cooking times
Why Altitude Matters
At higher altitudes, atmospheric pressure is lower. This reduced pressure means water boils at a lower temperature—about 1°C (1.8°F) less for every 300 meters (1,000 feet) of elevation gain.
At sea level, water boils at 100°C (212°F). In Denver, Colorado (1,609m/5,280ft), it boils at about 95°C (203°F). On the summit of Mount Everest (8,849m/29,032ft), water boils at only 70°C (158°F)!
How Eggs Cook
Eggs cook through protein denaturation—heat causes the proteins to unfold and bond together, changing the egg from liquid to solid.
The egg white (albumen) begins to set around 62°C (144°F) and fully sets at about 80°C (176°F). The yolk proteins start setting at 65°C (149°F) but need higher temperatures for a fully firm texture.
This is why at high altitudes, where water boils at lower temperatures, eggs need more time to reach the same internal temperature and doneness level.
The Math Behind the Time
Our calculator uses a combination of factors to determine your perfect boil time:
Base Time: Determined by egg size and desired doneness (soft, jammy, or hard).
Altitude Adjustment: For every degree below 100°C that water boils, cooking time increases by approximately 2-3%.
Starting Temperature: Eggs from the refrigerator (~4°C/39°F) need slightly more time than room temperature eggs (~20°C/68°F).
Batch Size: More eggs absorb more heat from the water, slightly increasing cook time for batches larger than 4 eggs.
Cold Water vs. Hot Water Start
Hot Water Start: Add eggs to already boiling water. This method gives more precise timing because you know exactly when cooking begins. It's ideal for soft and jammy eggs where timing precision matters most.
Cold Water Start: Add eggs to cold water and bring to a boil together. This gentler method reduces thermal shock and cracking. The trade-off is less precise timing since boil time varies by altitude and stove power.
Our calculator accounts for both methods, adding extra time for the cold-start approach.
Food Safety Note
At very high altitudes (above 3,000m/10,000ft), water boils below 90°C (194°F). While eggs may still cook, they may not reach temperatures sufficient to kill certain bacteria.
For food safety at extreme altitudes, consider:
- Using a pressure cooker (raises the boiling point)
- Extended cooking times
- Pasteurized eggs for recipes requiring soft yolks
Always ensure eggs reach at least 71°C (160°F) internally for food safety.