We've found a method to make perfect hard-boiled eggs, but how do you peel the suckers? There are a lot of different theories out there, but one that is especially intriguing involves adding a little baking soda to the cooking water. Could this small step produce pretty eggs that peeled smoothly from their shells every time? I had to test it and find out.
The Original Tip
This tip pops up all over the place, but the most reliable source is Harold McGee, who discusses the science behind why this works in his definitive food science book, On Food and Cooking:
Difficult peeling is characteristic of fresh eggs with a relatively low albumen pH, which somehow causes the albumen to adhere to the inner shell membrane more strongly than it coheres to itself. At the pH typical after several days of refrigeration, around 9.2, the shell peels easily. If you end up with a carton of very fresh eggs and need to cook them right away, you can add a half teaspoon of baking soda to a quart of water to make the cooking water alkaline (though this intensifies the sulfury flavor).
He points out that cooking the eggs a little longer and allowing them to chill in the refrigerator after cooking will also make fresh eggs easier to peel.
The Testing Method
I tried this technique twice, the first time with eggs that had been in my refrigerator for a little under a week, and the second time with eggs I had purchased two days before.
Both times I boiled four eggs at a time, two in a pot with a quart of plain water and two in a pot with a quart of water plus a half teaspoon of baking soda. I started the eggs in cold water, brought them to a rolling boil, took them off the heat and let them sit, covered, for 10 minutes. I transferred them to separate ice baths until they were fully cooled, and then the real fun began: peeling!
My results were very mixed.
In the first batch, the two eggs cooked in plain water were fairly easy to peel. There were a couple spots where the shell stuck firmly to the white, but overall both eggs were pretty enough to turn into party-worthy deviled eggs. The first baking soda egg that I peeled was noticeably easier, with the shell coming off in smooth, satisfying sheets. But the second baking soda egg was much worse, sticking all over the place and ultimately looking sad and chewed up.
What happened? I tried the test again with a batch of slightly fresher eggs.
This time, all four eggs peeled fairly easily with just a few sticky spots. The prettiest, most perfectly peeled egg of the bunch was one cooked in plain water; both of the baking soda eggs had some sticking that caused minor imperfections.
Overall, the baking soda did not make a consistent, noticeable difference in how easily I could peel the eggs.
- Plain water eggs: 2 fairly easy to peel
- Baking soda eggs: 1 very easy to peel, 1 very difficult to peel
- Plain water eggs: 1 very easy to peel, 1 fairly easy to peel
- Baking soda eggs: 2 fairly easy to peel
Verdict: This is not a mind-blowing tip
I am not the only one to find that this trick doesn't make a huge difference. Russ Parsons of the Los Angeles Times wrote about his adventures in finding the best method for easy-to-peel hard-boiled eggs, and concluded that adding baking soda to the water imparted a sulfury smell, but not much else. Instead, he found that cracking the cooked eggs slightly before putting them in an ice water bath made them easier to peel — and letting the eggs sit in the water for about 45 minutes was even better.
Adding more than a half teaspoon of baking soda to the water might give you better results, but I wonder if the sulfur smell might be more noticeable. (I actually didn't detect much of a difference in the smelliness of the baking soda eggs.)