When you see a green ring around an egg yolk, it’s a sign that the egg has been overcooked, typically due to prolonged boiling at high temperatures. This greenish or gray ring forms because of a chemical reaction between sulfur in the egg white and iron in the yolk, which results in the formation of ferrous sulfide.
Is it safe to eat?
Yes — it’s completely safe to eat. The discoloration doesn’t mean the egg is spoiled or harmful; it only affects appearance and sometimes texture.
Potential downsides of eating overcooked eggs frequently:
While the green ring itself isn’t dangerous, habitually overcooking eggs can have a few drawbacks:
- Reduced nutritional value: Prolonged heat can slightly degrade certain heat-sensitive nutrients like vitamin B12 and antioxidants.
- Rubbery texture: Overcooked eggs become tough and less palatable, which may impact digestion or enjoyment.
- Increased sulfur smell: The more eggs are overcooked, the stronger the smell due to sulfur compounds — unpleasant, but not dangerous.
For best results, boil eggs for 9–12 minutes and cool them in ice water to prevent the green ring from forming.