Shocking your recently boiled eggs by submerging them into a bowl of ice water is key. The quick cooling of the hard-boiled eggs causes the egg whites to contract, freeing them from the membrane. If you let them cool for about 15 minutes, the peeling is much easier.
Once the eggs have cooked to your preferred time, use the skimmer to remove the eggs and immediately submerge them in the ice water bath to stop them from cooking. You'll let the eggs sit here for about 5 to 10 minutes before peeling.
To avoid getting a green yolk, cook your eggs just long enough to reach the desired doneness—no more. And quickly plunge the cooked eggs into cold water to stop the cooking process and minimize the iron-sulfur reaction. Some people also say that the cold-water plunge makes eggs easier to peel.
Lower your eggs straight from the fridge into already-boiling water, or place them in a steamer insert in a covered pot, steaming at full blast on the stovetop. If boiling, lower the heat to the barest simmer. Cook the eggs for 11 minutes for hard or six minutes for soft.
Ideally, peel the eggs as soon as they're cool. Start at the broad end, and hold the egg under running water to loosen any bits of stubborn shell clinging to the sides. Another thing to keep in mind is the freshness of your eggs.
For maximum freshness, leave them in their shells until you are ready to eat or prepare. The shell will help to protect the egg from bacteria, and can help prevent them from absorbing odors from other foods in your refrigerator.
If you soak this egg shell in vinegar (which is about 4% acetic acid), you start a chemical reaction that dissolves the calcium carbonate shell. The acetic acid reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that you see as bubbles on the shell.
Use Vinegar & Baking Soda
White vinegar is a natural solution that can be utilized to dissolve calcium buildup. Sitting overnight, you will be able to remove lime buildup from the drain while avoiding the harsh chemicals in traditional drain cleaners.
The reaction of the eggshell in vinegar is an acid-base reaction. When you submerge an egg in vinegar, the shell dissolves, leaving the inner semi-permeable membrane intact. Vinegar (acid) breaks apart the solid calcium carbonate crystals (base) in the eggshell into their calcium and carbonate parts.
They're inexpensive, and fairly easy to make. That is, for everything but the peeling. To hard boil the perfect egg, put your eggs in a pot, and fill with cold water until the eggs are covered. Now, add ¼ cup of vinegar, and a teaspoon of salt into the water as well.
Result: The egg becomes stained with cola and can be removed by the toothpaste. *You could add in an extension activity to this, where you get kids to leave the egg in cola for 24 hours.
What happens? Be careful, the eggshell will be a lot weaker! If you leave the egg in the vinegar for about 36 hours, eventually all the calcium carbonate will be dissolved by the acetic acid, leaving just the soft membrane and yolk behind.
Add salt and vinegar to the water.
The salt permeates the shell a little bit, and the vinegar helps to break down the shells, making them easier to peel.
The vinegar in the water makes the eggs easier to peel. Here's why: The vinegar's acid not only dissolves some of the calcium carbonate in the shell, it also helps the whites set faster. Running the hard-boiled eggs under cold running water as you're peeling, meanwhile, helps the shell separate from the membrane.
This is because the egg white or “albumen” in a fresh egg has a relatively low pH level, making it acidic. When cooked, these fresh egg whites bond strongly to the inner shell's membrane. As an egg ages, the pH level rises and the inner membrane is less likely to bond to the albumen, so the shell peels off much easier.
You're seeing a reaction between a compound in the eggshell (calcium carbonate) and an acid in the vinegar (acetic acid). This reaction creates carbon dioxide (and some other things) and breaks down the eggshell in the process. The membrane underneath the shell doesn't react, so it's left behind.
Adding vinegar to the water helps the proteins in the egg white coagulate faster which further plugs any cracks in the egg.