What happens if you boil an egg for 30 minutes?

Boiling an egg for 30 minutes will result in a very hard-boiled egg with a dark, greenish-grey yolk.

Here's why:

* Overcooked white: The egg white will become tough and rubbery.

* Overcooked yolk: The yolk will become very firm and dry, and may even turn a greenish-grey color due to the iron in the yolk reacting with the hydrogen sulfide released during cooking.

* Potential for cracking: Over-boiling can cause the egg to crack and leak.

While technically edible, a 30-minute boiled egg won't be very pleasant to eat. It's best to stick to the recommended boiling times for different levels of doneness.

Here's a general guide:

* Soft-boiled: 3-5 minutes

* Medium-boiled: 6-8 minutes

* Hard-boiled: 10-12 minutes

Enjoy your perfectly boiled eggs!