Why is the yolk of my hard-boiled egg turning green?

Have you ever peeled a hard-boiled egg only to discover, to your horror, a thin green border around the yolk? Let's face it, we've all had that moment of doubt: "Is it still good?" Rest assured, your eggs are neither spoiled nor ruined. This phenomenon, while unsightly, has a very simple explanation… and, more importantly, an easy solution to avoid it forever!

Why does this greenish circle appear?

Les jaunes d'œufs durs vert foncé sont-ils sans danger pour ...

A small chemical reaction is behind this strange color. When eggs are cooked for too long or at too high a temperature, the iron in the yolk reacts with the sulfur in the white. The result: a compound called  iron sulfide  forms, leaving this greenish-gray ring around the center of the egg.

But don't panic: it's just a natural reaction, with no health risks. The taste remains unchanged; only the appearance suffers. And if you like perfectly yellow eggs, there's a foolproof method to avoid this culinary mishap.

The foolproof method for perfect hard-boiled eggs

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