I made an omelette today, and it turned out gray. I'm supposing this is because I did some things wrong, the question is what?

  • Beating the eggs too long
  • Mixing the eggs with cream cheese before beating the eggs
  • Too much oil in the pan

My guess is the first two reasons. Do you think that's likely or could it be something else?

  • The pan is a non-stick (probably teflon). I didn't stir, but did flip. The gray was throughout.
    The pan is new, but has seen some use already and is not defective as far as I can tel
  • The cheese is Kraft Philadelphia. I mixed the cheese, the other day, with walnut, hazelnut and chive. Straight from the fridge into the, fresh, unstirred, eggs.
  • 2
    Given that you had both eggs and aliums in there, I guess you created some metallic sulfate compounds, which are usually green/blue, but in combination with the yolk look grey. (The same mechanism as getting a green surface on the yolk of a hardboiled egg). I don't however know what your possible source of iron or copper ions is, especially with a coated pan.
    – rumtscho
    Sep 24, 2011 at 21:36
  • @rumtscho, thanks for using alliums on me :-) The source for iron could be the hazelnut 4,7mg. The walnut provides 0,4mg copper and 0,73mg iron. Sep 24, 2011 at 21:51

6 Answers 6


I have a theory about your omelette (and sadly, no means to test it). But I think it is plausible, please feel free to point out logical errors.

I think that the unappetizing coloring is due to the creation of sulfur salts in your pan. Egg whites are rich in sulfur, as are all alliums (including chives). If you heat them enough (you don't mention whether you overcooked the omelette, but it happens often enough), the heat changes the molecules in which the sulfur is bound, and the sulfur atoms (or sulfur containing ions) are free to react with whatever they find around. If they happen to find iron or copper, they form sulfides and sulfates with them. These sulfides and sulfates have colors ranging from blue to green, and pure iron sulfide is black. A mixture of them with the yellow yolk can easily look gray, especially when the color is desaturated through the addition of white cream cheese.

You say you used a coated pan, but there are still possible sources for the iron and copper. First, nuts contain trace elements, including iron and copper. Second, yolks too contain iron (in fact, the bluish coloring on the surface of a hard boiled yolk is an iron sulfide created when the proteins in the egg white denaturated from the heat). Third, you can't exclude contamination of the ingredients (plants sometimes store metal ions from the environment).

I have no way to prove any of the above, but at least it sounds like a good working theory. But I will understand if you aren't eager to reproduce in order to investigate the effect closer.

  • I think it's a nice enough theory. I did use more heat than other times because normally the omelette doesn't develop a crust. However, the omelette was by no means overcooked. I was going to reproduce the effect beating the eggs less and adding the cheese later, but haven't gotten around to do it yet. Sep 25, 2011 at 16:29


While I love Rumtscho's highly chemical theory above and will probably use it to explain why my own cooking doesn't look right in the future, I have a more mundane explanation, based you the information you omitted from your original question (bad submitter!):

Kraft Philadelphia. I mixed the cheese, the other day, with walnut, hazelnut and chive. Straight from the fridge into the, fresh, unstirred, eggs.

The walnuts are critical here. Cooked walnuts exude a powerful blue-purple dye. Walnut sourdough bread, for example, is frequently purple inside. I think your eggs were grey because of the walnuts, and not because of beating too long, the cream cheese, or the pan.

  • 1
    I'm afraid I'll come with my chemistry again. This powerful blue dye is iodine from the walnuts reacting with the starch in the dough. The omelette as listed doesn't have enough starch for the reaction to happen. (It has to be starch and not other carbohydrates). But yes, good observation.
    – rumtscho
    Sep 25, 2011 at 20:07
  • 1
    Bad submitter... I did say cream cheese. I never thought the walnut, hazelnut or chives could have that impact. Sep 25, 2011 at 21:20
  • rumtscho, I will have to cede any chemistry argument to you, since I'm a software geek who stopped at high school chemistry.
    – FuzzyChef
    Sep 26, 2011 at 0:02

I'm not sure if this is traditional omelette technique or not, but I always thought that you start with the beaten eggs (maybe some salt and pepper), alone, in the pan. Once it's semi-set, then additions go on one half of the omlet - cheese, cooked or raw veggies, whatever - and then as you slide it onto the plate, you fold the half without the additions over the side that does.

In any case, with less substances mixed into the actual uncooked eggs, there's less likelihood of interaction between eggs and items that might alter the flavor or appearance of the base ingredient.


I made scrambled eggs and forgot about them on the stove, when I came back the bottom was overcooked and the top was fluffy. I added nothing to the scrambled eggs and the eggs had a gray greenish color. Since it was only eggs that I was cooking and nothing was added I believe the pan is what makes the eggs the greenish gray color


I think this is a process where the iron the pan and egg combines with oxygen in the atmosphere. And the greyish color is iron oxide. Hard boiled eggs also tend to form a greyish color. I believe its the same reaction


I cooked 2 scrambled eggs in the microwve at work for 1 minute and 35 seconds and they turned out that bluish greenish gray color. In this case I think they were over cooked as the microwave at work seem to be higher power

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