Many home cooks are often puzzled by the green or gray ring that sometimes appears around the yolk of hard-boiled eggs. Though it may look unappetizing, it’s harmless and simply the result of a chemical reaction between the iron in the yolk and sulfur in the white, caused by overcooking. Fortunately, this reaction is easy to avoid with proper technique. To begin, place the eggs in a single layer in a pot and cover them with cold water, about 3 to 5 centimeters above the eggs. Heat the pot over medium heat, and once the water reaches a full boil, immediately remove it from the heat and cover with a lid. Let the eggs cook gently in the residual heat for 9 to 12 minutes, depending on the desired firmness.

After cooking, quickly transfer the eggs to a bowl of ice water or very cold water to stop the cooking process. This not only prevents the green ring from forming but also makes peeling easier. Let the eggs cool for about five minutes, and for even easier peeling, try doing it under cold running water. For best results, use eggs that are 5 to 7 days old, as they tend to peel more easily. Adding a bit of salt or vinegar to the water during boiling can help prevent cracking. Properly storing cooked eggs afterward ensures they remain fresh and safe to eat. With these simple steps, you can achieve perfect hard-boiled eggs every time.