A green ring around a hard-boiled egg yolk may look unappetizing, but it’s harmless. It happens when “iron in the yolk reacts with sulfur in the white” during overcooking, creating iron sulfide.
The best fix is controlling cooking time. Bring water to a boil, add the eggs, then simmer—don’t boil—for 9 to 12 minutes, depending on egg size.
Cooling is just as important. “Transfer eggs immediately to an ice bath or cold water” to stop cooking and prevent the ring. Quick cooling also makes peeling easier.
Older eggs peel better than very fresh ones, so they’re ideal for boiling. Store hard-boiled eggs in the fridge if you’re not eating them right away.
With careful timing and cooling, you’ll have perfect eggs—tender, tasty, and free of green rings.
