You’ve made hard-boiled eggs for your salad, and then—surprise—a green circle surrounds the yolk. It’s common, but far from appetizing. Even if you followed your instructions exactly, you might wonder why this happens and how to avoid it without needing professional culinary skills. Here are our tips for achieving perfect hard-boiled eggs that look as good as they taste.

**The culprit: An unexpected chemical reaction**
That iconic greenish ring isn’t the result of a poor-quality egg or a failed cooking attempt. It is simply a reaction between the iron in the yolk and the sulfur in the white caused by overcooking. The result is a layer of iron sulfide, which is nontoxic but visually unappealing. Fortunately, a few adjustments are enough to eliminate the issue.

**The surefire method for flawless hard-boiled eggs**

**Start cold**
Place the eggs in a pot without crowding them. Cover the eggs with cold water, ensuring there is about 3 to 5 cm of water above them.

**Heat gradually**
Cook over medium heat. When the water begins to boil, turn off the heat immediately.

**Let time do the work**
Cover the pan and let the eggs soak in the hot water for 9 to 12 minutes, depending on their size. For a slightly soft yolk, 9 minutes is perfect; for a firm yolk, allow up to 12 minutes.

**Express cooling**
Prepare a bowl of ice water. Plunge your eggs into it as soon as the resting time is over. This immediately stops the cooking process, prevents the green ring, and makes peeling easier.

**Peeling without stress**
Once cooled (5 minutes is sufficient), peel the eggs under cold running water to easily remove the shell.

**Bonus tips for a perfect result**
* Use eggs that are slightly less fresh; a very fresh egg is more difficult to peel. This method works best with eggs that are 5 to 7 days old.
* Add a pinch of salt or a dash of vinegar to the water to prevent the egg white from leaking if a shell cracks during cooking.
* Store eggs in their shells in the refrigerator for up to a week. Once peeled, consume them within 2 to 3 days.

The secret is simply ideal timing. There is no need to complicate things: the trick to avoiding the green ring is to avoid overcooking your eggs and to chill them immediately. It is an easy habit to develop for hard-boiled eggs that are both beautiful and delicious.