You're looking forward to devouring that egg you just hard boiled, but once you start cracking the shell and peeling it, you're not having a great time because it doesn't peel easily and — wait, why are there chunks of egg coming off with the peel? Argh! As it turns out, there is one single, simple ingredient you can add to your water that will make hard-boiled egg peeling way easier.
Even better, it's not an expensive ingredient — it's vinegar, which you likely keep around your house "just in case." (Hey, it even cleans toilets!)
BuzzFeed tested out several different popular theories on how to hard boil eggs for the best peeling results. One of the easiest methods, that had similar results across the board, was the addition of vinegar to the boiling water.
Other methods were explored, such as whether it's better to add an egg to already-boiling water — or should you put it in the cold water first before firing up the stove? Is an ice bath after boiling necessary for great-peeling eggs, or is it a waste of time?
After extensive testing, using both fresh eggs as well as eggs that had been hanging out in the fridge for a week, it was discovered that adding a bit of vinegar (around 1 tablespoon for every 4 cups of water) helped break down the shell no matter what method was used to actually cook the eggs. Science tells us that the egg's shell is made of calcium carbonate, and the vinegar dissolves some of it, which makes peeling way easier (via Chowhound).
It was also discovered that dunking the egg(s) into an ice bath immediately after cooking helped some, but even the eggs that didn't receive the ice bath treatment were still pretty easy to peel.
So, the next time you set out to hard-boil eggs, add some vinegar to the boiling water, gently boil them for around 14 minutes (or to your desired doneness), and give them an ice-cold bath immediately after the timer beeps. You won't have to curse at your eggshells ever again.