FOOD NEWS
How To Easily Eliminate That Unwanted Green Yolk On Your Hard-Boiled Eggs
By Allie Ward
Hard-boiled egg yolks can sometimes develop a greenish-gray ring with a chalky consistency when overcooked, but you can prevent this with a few adjustments to your cooking time.
The egg authorities vary somewhat on this point, with the American Egg Board advising 12 minutes and the USDA recommending 12 to 15 minutes, depending on the egg's size.
However, most sources recommend immediately running cold water over the eggs after cooking or dunking them in an ice bath to stop the cooking process and prevent discoloration.
The green hue is safe to consume and is caused by a chemical reaction known as "ferrous sulfide formation" between the sulfur in the egg whites and the iron in the yolk.
Controlling the cooking time and giving your eggs an ice bath leaves you with yellow yolks, perfect for dishes like egg salad or deviled eggs, where they'll shine.