Dyeing Eggs

Easter is on April 1 this year, and it’s time to get in the spirit of spring! There are multiple traditional activities many people participate in this time of year, including hunting for hidden eggs, finding baskets with candy and other treats, and of course, dyeing eggs!

With a plethora of different colors to choose from, it’s no wonder why so many people dye their extra eggs during this time of the year. In the springtime, eggs symbolize new life and energy - plus they make great decorations!

Anatomy of an Egg

Last year, we discussed how baby birds develop inside their eggs, so let’s review the anatomy on an egg. The first part of an egg that you see is the shell. Egg shells have very diverse appearances, depending on the type of bird that laid it. Chicken egg, are usually white (which we will use for dyeing) or brown, though some chickens lay blue or green eggs! The surface of the shell is bumpy and grainy, due to the thousands of little pores that allow air and moisture into the egg. It’s made up almost entirely out of calcium carbonate (CaCO3) crystals.There’s also an outer coating on the shell, called the cuticle, that keeps out dust and bacteria.

Between the eggshell and the egg white, there are two membranes (inner and outer) that provide more defense against bacteria that may have slipped in through the shell. These layers are made of keratin; the same protein that makes up human hair.

An air space forms when the insides of the egg cool and contract after it’s laid. The air space is usually between the outer and inner membranes at the egg’s larger end, and it accounts for the crater you often see if you’ve eaten a hard-boiled egg. This air cell grows larger if it were left to age, and that’s why you should never eat an egg that floats--it floats because it’s old enough for the air space to cause the egg to float...and that makes it too old to eat!

The egg white is also known as the albumen, which comes from albus, the Latin word for “white.” Four alternating layers of thick and thin albumen contain approximately 40 different proteins, the main components of the egg white in addition to water.

The next component of an egg is the yolk. Contrary to popular belief, the yolk is not what develops into a baby bird if fertilized; it is the stockpile of nutrients that the baby bird uses to grow and develop inside the egg. The yolk contains less water and more protein than the white, some fat, and most of the vitamins and minerals of the egg. These include iron, vitamin A, vitamin D, phosphorus, and calcium, among others, making the yolk a great source of nutrition for a growing baby bird.


How the Dye Works

The colored molecules in food dye are sodium salts of phenolic acid, a naturally-occurring color compound found in the seeds and skins of fruits and vegetables. But we can’t just drip some food dye onto an egg and call it good - there are more steps involved! To make a dye mixture you need a mixture of water, vinegar, and food dye. When the dye is mixed with water, the sodium ions are dissolved and you’re left with the negatively charged part of the molecule, which is the colorful part.

When you add vinegar (which is diluted acetic acid), you’re actually flooding the dye with protons that they can bind to. Now that the dye molecules have combined with hydrogen ions, they can form hydrogen bonds. The slight positive charge the dye molecules now have are instrumental in binding to the slightly negative atoms in protein molecules and calcium carbonate of the eggshell.

So even though boiled eggs already have a slightly acidic smell, we still need to add vinegar in order for the food dye to work! The saturation of the colors on an egg depend on how well the dye bonds to the shell. This means that the less vinegar you use, the less vibrant your color will seem! However, if you don’t like the strong scent of vinegar, you can always use another type of acid - such as citric acid squeezed from a lemon! Just make sure that the pH of your dye solution is no lower than 4, or else carbon dioxide bubbles released when the acid reacts with the calcium carbonate in the shell will make streaks on your egg!

Dye Your Own Eggs!

In order for the dye to bind with your eggs, you should boil them first to make sure they don’t crack and make everything messy! To do this, gently place your eggs in a single layer in a large saucepan. Add enough cold water to cover the eggs by one inch. Cover the pan and bring the water to boil on high heat. Remove from heat and let stand 12 minutes. Pour out the hot water and rapidly cool eggs by running them under cold water (or place them in ice water) until completely cooled.

To make the dye, mix 1/2 cup boiling water, 1 teaspoon vinegar and 10 to 20 drops of food color in a cup to achieve desired colors. Repeat for each color.

Dip the hard-boiled eggs in dye for about 5 minutes. Use a slotted spoon, wire egg holder or tongs to gently add and remove your eggs from the dye. Make sure you allow them to dry before touching them! If you don’t leave them out for too long, you can eat the dyed eggs after you’ve used them as decorations.





Image Credits:


Egg diagrams property of Discovery Express Kids LLC.

Kratochvil Petr. “Colorful Eggs”. Released into the public domain. Uploaded on 3/28/17 from publicdomainpictures.net

Kratochvil, Petr. “Colorful Easter Eggs”. Released into the public domain. Uploaded on 3/28/17 from publicdomainpictures.net

Koev, Vladimir. “Easter Time”. Released into the public domain. Uploaded on 3/28/17 from publicdomainpictures.net