Dr. Seuss may have made green eggs and ham cool, but, when the yolks of our hard-boiled eggs end up with a grayish-green ring around the perimeter, it's just not as endearing as Sam I Am eating his green eggs in a tree. For aesthetic purposes, the ideal boiled egg yolk is a solid, yellow to orange color throughout.
When a ring around the yolk can be seen, it just doesn't look so appetizing. What may surprise some is that the green ring is completely avoidable and has nothing to do with the egg itself. The trick to avoiding any discoloration on the yolk is to not overcook your eggs and to cool them quickly when they're done.
Overcooking hard-boiled eggs is really easy to do because, in order to ensure the yolk is cooked all the way through with no soft or runny spots, many people will boil the eggs vigorously and then, perhaps, let them cool slowly until they can be handled. Sure, the eggs will cook, but at the expense of their even, buttery color. Instead of boiling, try simmering Despite the name "hard-boiled eggs," you can get your eggs fully cooked in the shell without any hard boiling at all.
There are several methods that promise to be the absolute (we're particularly partial to steaming, rather than boiling). However, if you want to cook your eggs submerged in water, then bringing water up to a boil in a pot first, placing the eggs in, and immediately lowering the heat to a gentle simmer is the way to go. After about 10 to 15 minutes (depending on the size of the eggs) .
