Worried you’ve ruined your hard-boiled eggs when you notice a greenish ring around the yolk? Rest assured: this common phenomenon is harmless and simply explained by the cooking process.
You’re preparing a salad or a picnic, and everything seems perfect… until you cut into the hard-boiled eggs. Surprise: a strange greenish ring surrounds the yolk. Not very appetizing, let’s face it! Should you be worried? Is this a sign that the eggs are no longer good? Or have you simply overcooked them without realizing it? Don’t worry, this little detail actually hides a much simpler explanation than it seems…
Why does a green circle appear around the egg yolk?

When an egg is exposed to heat for too long, a natural reaction occurs between the elements in the egg white and the yolk. The result: this thin greenish layer appears around the yolk.
Good news: this doesn’t affect the flavor or overall quality of the egg. It’s purely a matter of aesthetics… but we all agree, we prefer a bright, transparent yolk!
The real problem: uncontrolled cooking.
If this ring appears, it’s usually because the egg was cooked too long or at too high a temperature. Just like overcooked pasta, the quality of the finished product suffers.
Many people think they’re doing the right thing by boiling the yolk for a long time, but that’s exactly where the mistake lies. Overcooking alters the yolk’s consistency and appearance.
Fortunately, a few tricks are enough to avoid this inconvenience and obtain a result worthy of the most refined dishes.