According to Bowl of Delicious, this hack will ensure you have easy-to-peel hard-boiled eggs every time. Simply add 1 tablespoon of any type of oil, including olive, canola, or vegetable oil, to a saucepan of boiling water. As mentioned earlier, eggshells are porous, releasing carbon dioxide and moisture over time and forming air pockets. Have you ever heard of the hack where you put old eggs in a bowl of water to see if they go bad? If it sinks, you can still eat it, but if it floats, it means it’s too old. The larger the egg, the more air leaks into the shell, causing it to float.
Because eggshells are porous, oil can seep into the shell, forming a thin layer of oil between the shell and the egg white. This slippery layer of oil encourages the eggshell to glide satisfyingly upon peeling. It’s similar to rubbing oil with your finger to help it slide off a stuck ring.
