Overcooking eggs: Unveiling the mystery behind blue halos around egg yolks

Hard-boiled eggs are not just culinary essentials in salads, but also an indispensable part of the holiday table. It can be unsettling after cooking and slicing the egg, only to be greeted by a less appetizing grey or green halo around the yolk. People often (and inaccurately) consider this a sign that the egg is spoiled. However, this is not the case.

The cause of the unappealing outline is very simple - it is a result of overcooking. If we boil eggs longer than 10 minutes, a chemical reaction takes place, causing sulfur and iron to separate from the yolk. These two elements form a chemical compound known as iron sulfide, recognizable by its grey color. Nonetheless, there is no need for worry - such an egg is perfectly safe to eat. The color change only affects the visual appeal, having no impact on the egg's taste and being harmless to health.

The one disadvantage of overcooking eggs, besides the color change of the yolk, is that it can lead to losing the product's nutritional value. But if you don't enjoy soft-boiled eggs, you can still hard-boil them without the color change. Such eggs should be boiled for 7-8 minutes from the moment the water boils. This will help maintain the yellow hue of the yolk. Once that time is up, rinse the eggs with cold water to halt the cooking process.

Adding 2-3 tablespoons of salt to the cooking container can be quite beneficial. This simple trick makes it easier to peel the eggs later. Baking soda can likewise make the peeling process smoother. Once the egg is cooked, gently tap it against the edge of the pot or kitchen counter to crack the shell. When the eggs have cooled down, you can proceed to peel them.