A greenish-gray ring may appear around a hard-cooked egg yolk. … The reaction is usually caused by overcooking, but can also be caused by a high amount of iron in the cooking water. Eliminate the ring by avoiding overcooking and by cooling the eggs quickly after cooking.
Are grey hard boiled eggs OK?
It turns out that hard boiled eggs can take on that greenish gray color around the outside of the yolk because of a chemical reaction between the iron in the yolk and sulfur, which is present in the white. … That said, besides being a bit on the rubbery side, an over-boiled hard boiled egg is still fine to eat.
How do you boil an egg without the yolk turning grey?
Cover them with cold water and place the pot over high heat. Bring the water to a boil and as soon as it reaches a rolling boil set a timer for 5–7 minutes, depending on how you like your eggs. When the timer is finished, immediately dump out the boiling water and rinse them with cold water to stop the cooking process.
Why are my cooked eggs grey?
The greenish-grey colour found in cooked eggs is due to the formation of ferrous sulfide. Eggs contain all 20 amino acids out of which cystine and methionine, two sulfur-based amino acids play a key role in this formation, that are present in large amounts in egg whites whereas elemental iron is abundant in yolks.
How do you know if an egg is bad after boiling?
The most noticeable sign that a hard-cooked egg has gone bad is the odor. What is this? If the egg has any sort of unpleasant, sulfurous, or rotten smell, it has gone bad and should not be consumed. If the hard-boiled egg is still in its shell, you may have to crack it open in order to notice any odor.
Can I eat overcooked hard-boiled eggs?
You should not eat overcooked eggs. … When you boil eggs, hydrogen sulphide – a toxic gas is released in the whites of the egg. This happens especially when you overboil the eggs. If you have noticed, overcooked eggs have a green coating on their yolk, which is a signal that you should not eat them.
Why do raw eggs turn black?
Black or green spots inside the egg may be the result of bacterial or fungal contamination of the egg. If you come across an egg with black or green spots discard the egg. Off color egg whites, such as green or iridescent colors may be from spoilage due to bacteria.
Are Floating hard-boiled eggs bad?
If it tilts upwards or even floats, it is old. This is because as an egg ages, the small air pocket inside it grows larger as water is released and replaced by air. If the air pocket becomes large enough, the egg may float. … An egg can sink and still be bad, while an egg that floats may still be fine to eat (3).
What does it mean when eggs float while boiling?
An egg can float in water when its air cell has enlarged sufficiently to keep it buoyant. This means the egg is older, but it may be perfectly safe to use. … A spoiled egg will have an unpleasant odor when you break open the shell, either when raw or cooked.