What makes ring around hard-boiled egg yolks?
Dear Heloise: What causes the dark-green or gray ring around the yolk of a hard-boiled egg, and how do you prevent this from happening? Much of the time, this seems to happen with eggs that I boil. — Margaret, via e-mail Dear Margaret: We checked with our friends at the American Egg Board and here is what they had to say: “When you cook eggs at too high a temperature or for too long at a low temperature, the surface of the yolks may turn gray-green.” The dark ring around the yolk is ugly but safe to eat. Here is the American Egg Board’s method of hard-cooking eggs: “Place eggs in a single layer in a saucepan. Add enough water to come at least 1 inch above the eggs. Cover and quickly bring to a boil. “Then turn off the heat. Let the eggs stand, covered, in the hot water for about 15 minutes for large eggs (12 minutes for medium). “Then run cold water over the eggs or place them in ice water. This stops the cooking process. Unfortunately, it’s almost impossible to cool eggs to this stag
