Everyone knows you can dye egg shells, but did you know you can change egg yolk color? Normally, chickens produce eggs with yolk colors ranging from pale yellow to deep orange. The colors largely depend on their diet. You can change the color of an egg yolk by changing what the chicken eats or by injecting a fat-soluble dye into an egg yolk.
Egg Color and Nutrition
Eggshell and yolk color are unrelated to the nutritional content or flavor of an egg. Chicken eggshell color depends on the breed of chicken. There are white, yellow, brown, brick, blue, and green chicken eggs. The shell thickness, cooking quality, and value of an egg are not affected by its color. No matter what color the shell is, the yolk color depends on the diet fed to the hens.
Can I Dye Egg Yolks?
Ordinary food coloring can be used to change egg white color, but won’t spread throughout an egg yolk. Egg yolks contain lipids, so you need to use a fat-soluble dye. You can find oil-based food dyes at Amazon and at cooking stores. To change egg yolk color, simply inject the dye into the yolk and allow time for the color to spread.
Changing Yolk Color at the Source
If you raise chickens, you can change the color of the yolks of the eggs they produce by controlling their diet. Specifically, you control the carotenoids or xanthophylls they eat.
Carotenoids are pigment molecules found in plants, responsible for the orange of carrots, red of beets, yellow of marigolds, purple of cabbages, etc. Certain commercial pigments are available as supplements added to feed to influence egg yolk colors, such as BASF’s Lucantin(R) red and Lucantin(R) yellow. Natural foods also affect yolk color. White, yellow, orange, red, olive green, and possibly purple may be obtained, but for deep blue and green you have to resort to dyes.
Foods That Influence Egg Yolk Color
| Yolk Color | Ingredient |
| nearly colorless | white cornmeal |
| pale yolks | wheat, barley |
| medium yellow yolks | yellow cornmeal, alfalfa meal |
| deep yellow yolks | marigold petals, kale, greens, alfalfa |
| orange to red yolks | carrots, tomatoes, red peppers, hot peppers |
| olive green | cottonseed meal, acorns, shepherd’s purse |
| greenish black | silage, grass |
Hard-Boiled Green Egg Yolks
Although the color options are limited, it’s possible to change egg yolk color by cooking eggs. You can get grayish-green egg yolks by overcooking hard boiling eggs. The discoloration results from a harmless chemical reaction in which hydrogen sulfide produced by sulfur and hydrogen in the egg whites reacts with iron in the yolks. Few people consider this an attractive food color, so you may wish to prevent this reaction by immediately chilling eggs with cold water after hard boiling them.
Another reason yolks may turn gray or green is if there is iron in the cooking water. Green rings result from iron in the hen’s feed or water. Scrambled eggs may turn green if they are left overly long on a steam table.
Foods served with eggs also affect their color. For example, serving blueberry pancakes with soft cooked eggs may turn the yolk green.
References
- Attokaran, M. (January 13, 2011). Natural Food Flavors and Colorants. John Wiley & Sons. ISBN 978-0-470-95911-4.
- Damerow, Gail (January 31, 2012). The Chicken Encyclopedia – An Illustrated Reference. Storey Publishing. ISBN:978-1603425612.
- Saunder’s Eggs (March 23, 2018). What Do Different Eggshell Colors Mean?