A green ring around a cooked egg yolk is a sign that the egg was overcooked or cooked at too high a temperature.
This happens because sulfur in the egg white reacts with iron in the yolk, forming ferrous sulfide, which has a greenish-gray color.
✔️ It’s Safe to Eat
The discoloration looks odd but it’s completely harmless.
How to Prevent It
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Don’t boil eggs too hard or too long.
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Use a gentler cooking method (simmer, not a rolling boil).
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Cool the eggs quickly in ice water after cooking—this stops the reaction.
If you want, I can give you perfect timing instructions for hard-boiled eggs!
