Why Does a Hard-Boiled Egg Have a Green or Gray Ring Around the Yolk?
You cut open a hard-boiled egg expecting to see a bright yellow yolk, but instead there is a strange grayish-green ring around it.
At first glance, it can look like something is wrong with the egg.
The good news is that a green ring around an otherwise normally cooked egg yolk is usually caused by a cooking reaction, not mold or spoilage. The reaction happens between sulfur compounds in the egg white and iron in the yolk.
