It’s merely a reaction between the iron in the yolk and the sulfur in the white that results from overcooking. The end outcome is a little layer of iron sulfide, which is nontoxic but visually unattractive. Fortunately, a few changes are sufficient to eliminate this issue.
Quick Tip: Hard Boiled Eggs (without that gray-green ring around the yolk) – Diane’s Food Blog
The surefire way for making flawless hard-boiled eggs
Begin chilly.
Place the eggs in a pot without crowding them. Cover the eggs with cold water, leaving about 3 to
