These two hacks were tested to see which of them actually work. Adding vinegar to boiling water made it easier to peel. Adding baking soda made it almost impossible to peel.
Because older eggs have more alkaline, you shouldn't add vinegar to the cooking water, though some recipes recommend it. Adding about a teaspoon of baking soda to the cooking water increases the alkalinity, which will make the eggs easier to peel later on.
Egg Peeling Method #1: Boiling Eggs with Baking Soda
The higher pH of older eggs allows the whites to separate from the inner shell membrane, which makes them easier to peel. The baking soda method of boiling eggs aims for the same result.
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.
Use a spoon.
Crack the eggs at the fat end and peel a tiny bit with your fingers. Slip a spoon under the shell so that the curve of the spoon follows the curve of the egg. Rotate the egg and move the spoon to release the shell. This is a great method if you're only peeling a few eggs.
"Get them onto a spoon and drop them into the water", Gordon said, timing six minutes to boil the eggs. "Bring that [the water] to the boil, but don't water them ferociously, or you'll get a black line around the outside, boil them gently."
These two hacks were tested to see which of them actually work. Adding vinegar to boiling water made it easier to peel. Adding baking soda made it almost impossible to peel.
Apparently super fresh eggs are difficult to peel because the pH of the white is more acidic which causes it to adhere to the shell membrane more tightly.
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.
Add baking soda. Place saucepan onto stovetop at medium-low heat and bring to a boil for 1 minute. Cover and remove the saucepan from the heat and allow to sit for 12 minutes. Remove eggs from water with a slotted spoon and plunge into a bowl of ice water to stop all cooking.
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.
Add a few drops of vinegar and see the magic. The acetic acid reacts and the process of beating eggs can be completed in half the time. Also, the egg whites will remain fluffy for long.
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.
These are bubbles of carbon dioxide gas from the reaction. It can take 12-24 hours before a good portion of the shell is removed. A good sign of progress is a white frothy scummy layer on the top of the surface of the vinegar. After a day of soaking you can carefully remove the egg from the vinegar.
Those bubbles are full of carbon dioxide, just like the bubbles in a glass of soda. 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.
Kenji López-Alt's James Beard Award–winning The Food Lab suggests (after many, many rounds of tests) lowering eggs into boiling water for 30 seconds, then adding ice cubes, reducing to a sub-simmer, and cooking for 11 more minutes.
Baking Soda
According to our friends at Delish, adding a teaspoon of baking soda to your boiling pot of water will help the shell peel off seamlessly. Why? The alkaline in the baking soda will help your egg whites loosen up from the shell, making it easier to peel.
Carefully place the eggs in a large saucepan; add cold water to cover by one inch, and bring to a rolling boil. Cover pan; remove from heat. Let stand 12 minutes, then drain and rinse under cool water. To store, keep eggs unpeeled in the refrigerator, up to 4 days.
unrefrigerated? As with all cooked foods left out at room temperature (aka the Danger Zone), hard-boiled eggs are no longer deemed safe after two hours. Instead, drop the eggs post-boil in a bowl of ice water, and transfer the cooled eggs to the fridge for longer shelf-life.