Grey Eggs: Are They Safe To Eat Or Not?

A spoiler of what should have been a good meal is hard-boiled eggs with a grey color on the inside.

It could be unattractive and can make you lose your appetite and get worried. If you love to eat hard-boiled eggs, you’re probably not new to the grey hue around the eggs.

Perhaps you’ve paused for a moment and have wondered if these eggs are still safe to eat, especially if you don’t find them very appetizing. Before you throw the eggs away or for the sake of a next time, you should read this article.

Why do eggs turn grey?

Eggs turn grey when they have been overcooked.

Cooking eggs for too long triggers a chemical reaction between the metals eggs contain.

Egg white contains hydrogen and sulfur which form hydrogen sulfide gas when you cook the egg. When you cook eggs for too long, the hydrogen sulfide gas meets iron in the egg yolk.

The reaction forms ferrous sulfide, which is the grey color you see around the point of contact between the egg white and the yolk.

Can raw eggs turn grey?

Raw eggs do not turn grey.

However, if you find a greenish hue in raw eggs after breaking them, it could be because they are past their prime.

Why do hard-boiled eggs turn grey?

Hard-boiled eggs are grey because you have cooked them longer than you should. The greyish color is because of a reaction that has happened between the egg white and the yolk.

Boiled eggs quickly turn grey around the yolk because the heat from boiling removes the protective coat that protects the egg from bacterial action.

However, hard-boiled eggs are nutritious and highly satisfying because of their high protein content.

Why do scrambled eggs turn grey?

Scrambled eggs turn grey when you have cooked them for too long.

The grey color is a sign of a reaction between the egg white and yolk that led to the release of ferrous sulfide.

Is it safe to eat grey eggs?

Yes, it is. The United States Department of Agriculture (USDA) says it is safe to eat eggs that have a grey color around the yolk.

The grey color is not a sign of a living organism or an adverse reaction in the egg. It is a sign that the egg has been cooked for too long.

Although it may look unappetizing, it is harmless. However, because hydrogen sulfide and ferrous sulfide are toxic compounds, you should not always eat overcooked eggs.

If you eat grey eggs in moderation, you should not experience any side effects.

How can you prevent eggs from turning grey?

Cook eggs with a timer

The best way to prevent eggs from turning grey is not to overcook them. This is possible if you use a timer when cooking the eggs.

Set the timer according to the level of doneness you desire for the eggs. Also, do not be far from your pot of boiling eggs.

Cool the boiled eggs immediately

When you have mistakenly overcooked eggs, quickly put them in a bowl of cold water to stop the cooking process. Leave the eggs in the water until they are cool.

Cook fresh eggs

When you cook old eggs, you may have to cook them for a longer period to get them firm because they are runnier than fresh eggs.

Also, you may find yourself cooking them longer than usual because you want to kill any bacteria that you think are on or in the eggs. In addition, old eggs release sulfur which makes them turn grey quickly.

Cook eggs slowly

This solution applies to both scrambled and boiled eggs. Cooking eggs slowly over low heat will greatly help you achieve cooked eggs without overcooking them.

Also, watch out for signs of doneness in scrambled eggs, for instance. When scrambled eggs are done, they’ll look fluffy and bright yellow. Take the pan off the heat immediately after the eggs are done cooking.

Make use of a nonstick pan

This applies to scrambled eggs. Making scrambled eggs in a nonstick pan will reduce the chances of overcooking them.

Other signs that cooked egg is bad

The smell

Cooked eggs have an offensive smell when they go bad. They smell of sulfur or rottenness. If you notice this off smell with your cooked eggs, throw them away.

However, if you use only the smell to detect spoilage in hard-boiled eggs, it could be misleading. So, you should continue to examine the eggs using the other signs below.

Color of the eggs

If the eggs appear dark green or too grey, they are probably no longer good to eat. Also, if the yolk is brown or green with mold, it is no longer good and you should not eat it.

Be sure that you’re not mixing up the color of mold on eggs with the grey color of overcooked eggs.


If scrambled eggs feel drier than when you first made them, they have gone bad. However, do not rely only on this sign to determine spoilage because it could be because you did not cook the eggs with enough oil.

Bad taste

If you are finding it difficult to determine if the eggs are bad because they still look fit, you should take a bite.

Take a bite of the egg. If it tastes slimy or rubbery, do not eat them.

How to preserve cooked eggs

  • Keep unpeeled hard-boiled eggs in the refrigerator
  • Put peeled boiled eggs in a bowl of water and keep them refrigerated
  • Also, keep cooked eggs frozen
  • Pickle hard-boiled eggs to keep them longer


Can you eat grey egg yolk?

Grey egg yolk is a sign that you overcooked it, and it is safe to eat as long as it has not gone bad.

Can you eat grey egg white?

You can safely eat grey egg white if you’re sure that you only overcooked it. You must also be sure that the egg is still in good condition by examining it for signs of spoilage.

Are overcooked eggs poisonous?

Eating overcooked eggs can become poisonous sooner or later, especially when you eat too much of them.

Overcooking eggs releases toxic compounds such as hydrogen sulfide and ferrous sulfide into the yolk. When these compounds accumulate in your body, you may get sick.


The icky grey color on boiled eggs that always put you off isn’t what you think it is. Grey hard-boiled eggs are not harmful.

As said earlier in the article, the grey color is due to a reaction between the sulfur in the egg white and the iron in the yolk. This reaction occurs within the egg while it cooks. You may also notice this phenomenon with scrambled eggs if you overcook them.

If you can take your mind off the unattractive color, you should be able to eat the eggs. However, you should only eat the egg if you’re sure that it has not gone off.

Thanks for reading.

Read resourceful articles on food storage, preservation, and spoilage on Millenora.