Egg Yellow
That was quick! Reader Sue asks: why do some eggs have darker yolks than others, and does a deep yellow color mean the yolks are more nutritious?
As far as I know a deep yellow yolk isn’t necessarily more nutritious than a pale yellow yolk. However I do know what makes one yolk darker than another: the diet of the hen. Chickens are omnivorous scavengers, which means they’ll eat all different sorts of things…pretty much whatever they come across. Hens that “scratch” in the barnyard (or the suburban back yard, as the case may be) eat everything from grains and legumes to grasses, leaves, roots, insects, worms, mice…even the carcasses of dead animals.
On commercial farms chickens eat a grain feed made up of things like corn, rice, soybeans and peanuts. But that diet, unless it’s especially rich in corn, won’t necessarily deliver eggs with deep yellow yolks, which consumers definitely prefer. Alfalfa is something poultry farmers will sometimes add to chicken feed to enhance yolk color. Marigold petals are another, though as far as I understand it, they’re considered a “cheat” in agricultural circles. Why I don’t know. Possibly because they’re cheap!
It has been my experience that an egg’s freshness can effect the color of the yolk. Fresh eggs will be more vibrant, while older eggs begin to pale, looking washed out.
That seems right to me, actually. VERY old eggs I’ve had seemed to have paler yolks. Thanks Kenn!
hi joe, i was wondering why my sponge cakes always turn out yellow, even though i beat the eggs till they turn almost pale white; is it because of the egg yolks or the yellow butter..(in India, we have white egg shells with bright yellow yolks)
I’m pretty sure it’s just the yolks that provide the color. But that makes my wonder why the yellow in egg yolks is so resistant to fading either by heat or from chemicals. I need to look into that, might make an interesting post!
– Joe
In Western Australia, we’ve been selling our free range eggs for years, our eggs are darker orange in winter and spring (June to November) when they get fresh grass, light yellow through the summer months when the greens they get are dried. (lucerne)