One of the easiest foods to cook is, without a doubt, hard-boiled or boiled eggs. It’s hard to go wrong, we just have to boil the water and put them inside. But it can happen that once we take them out and peel them, we realize that a green or gray ring has appeared around the yolk of the hard-boiled egg. What is it and why is it produced?
What is the green or gray ring around the yolk of a hard-boiled egg?
If you have ever boiled an egg and after peeling it and cutting it in half you have noticed that a gray or green ring appears between the white and the yolk, surely you have wondered why that ring and especially if the egg it is eatable.
That gray or greenish color appears “simply” due to a chemical reaction during the boiling of the egg and yes, it is safe and the egg is safe to eat. It happens that surely the egg has been boiling too many minutes and that has caused a reaction of the sulfate compounds and iron in the egg.
To explain it in detail, we have to say that the egg proteins are held together by sulfur, which decomposes with the heat it receives when it is introduced (and kept) in boiling water and becomes hydrogen sulfide or sulfate. The latter combines with the iron in the egg yolk and can produce the result we often see.
Specifically, it is the iron sulfide that creates the gray (or green) rings around the egg , and as we say, this is usually the result of overcooking.
Therefore, it is not something serious that happens to the egg or that perhaps it is out of date, as much as this ring makes the egg less appetizing, it is just a sign that you have overcooked them. From a nutritional point of view , only a (very small and insignificant) part of iron was lost.
Finally, you should know that this greenish or gray layer in eggs can not only appear in the yolk of those that are cooked, but also scrambled eggs “suffer” if we make them too much or if perhaps we place them on a plate that is too hot. In that case we will see how the entire egg appears covered by a thin greenish layer , but again here we should not be alarmed since the eggs will be completely edible.
