That green ring around a hard-boiled egg yolk isn’t harmful—it’s just a result of overcooking. “It’s merely a reaction between the iron in the yolk and the sulfur in the white,” forming harmless iron sulfide. Luckily, it’s easy to avoid with the right steps.

Start with cold water. Place eggs in a single layer in a pot and cover with 3–5 cm of cold water. Bring to a boil over medium heat. When the water reaches a full boil, turn off the heat.

Cover the pot and let the eggs sit in the hot water for 9–12 minutes depending on size. “For a slightly soft yolk, 9 minutes is enough. For a firm yolk, allow up to 12 minutes.”

Immediately transfer eggs to an ice bath for at least 5 minutes. This stops cooking, prevents the green ring, and makes peeling easier.

Peel under running cold water for stress-free removal.

Use eggs that are 5–7 days old for easier peeling. Add a pinch of salt or vinegar to prevent cracking. Keep unpeeled eggs refrigerated for up to a week; peeled ones, 2–3 days.

In short: don’t overcook, cool fast—“just the ideal timing” is the real secret.