What causes eggs to crack while boiling?

By Laura S. Harris
Apr 5, 2021

The bottom, rounded end of an egg contains a small air bubble. As the egg heats up, the air inside the bubble expands. As the hot air pushes outwards, it puts pressure onto the shell, making it crack. You can prevent this by making a pin-pick in the bottom rounded end of the egg.

Can you cook a cracked egg in boiling water?

Be sure to cook eggs thoroughly, with both the white and yolk firm, to a temperature high enough to destroy bacteria that might be present in the egg yolk or white. About the only thing you can't do with those cracked eggs is to boil them.

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References

• https://www.scienceofcooking.com (Apr 9, 2021) Boiled Eggs - Science of Cooking
• https://eggsafety.org (Apr 9, 2021) Can I still use cracked eggs? - Egg Safety Center