If you’ve ever noticed a greenish ring around the yolk of your hard-boiled eggs, you might have wondered what causes it. The green color is a natural result of a chemical reaction and isn’t a sign that your eggs are bad or unsafe.
This happens when eggs are cooked too long or at too high a temperature. The sulfur in the egg white reacts with the iron in the yolk, producing ferrous sulfide, which shows up as a green ring. This can also happen in scrambled eggs or omelets if they’re overcooked. The eggs remain safe to eat, and their flavor and nutrition stay intact.
To prevent green yolks, cook your eggs gently. Bring water to a boil, then lower it to a simmer before adding eggs. Cooking for 9 to 12 minutes usually results in a nicely cooked yolk. After cooking, plunge the eggs into ice water to stop further cooking and make peeling easier.
Avoid high heat when cooking eggs in any form. The best eggs have a bright yellow, creamy yolk without any green tint. If you do end up with green yolks, get creative—try mixing them with avocado on toast for a tasty and visually appealing snack.
Green yolks are nothing to fear. With a bit of care in cooking and cooling, you can enjoy perfectly cooked eggs every time.
