Food Science: Why Are Hard-Boiled Eggs So Hard to Peel?

There are a million and one tips out there for how to make a hard-boiled egg easier to peel, but far fewer on why eggs are so hard to peel in the first place. Let's take a look, shall we?

One of the most frequently quoted peeling tips is that old eggs are easier to peel than fresh ones. It turns out this particular tip has some truth!

Harold McGee in On Food and Cooking explains that the white albumen in a fresh eggs has a low relatively low (ie, acidic) pH level. When cooked, these fresh egg whites bond more strongly to the inner shell membrane than it does to itself. As an egg sits in refrigeration for several days, the pH of the white albumen increases and the hard cooked eggs become much easier to peel.

If you get a sudden craving for egg salad and only have fresh eggs in the fridge, McGee suggests adding a half teaspoon of baking soda to the water to raise its pH and also cooking the eggs slightly longer to give the whites time to set firmly. The only downside is that this can make the eggs taste more sulfuric.

Do you have a tried and true method for peeling hard-boiled eggs?

Related: Look! Hard Boiled Peeled Eggs at Trader Joe's

(Image: Flickr member RatRanch licensed under Creative Commons)