Over the past three weeks, we have walked the path together on the journey to hard-boiled egg enlightenment. So far, I've discovered that the method of making hard-boiled eggs that I've been using for the last two decades can definitely be improved upon. With the conclusion of this fourth week of testing, not only will I be able to draw conclusions about the three experimental methods I've selected, but I will also be able to look at the results over time, thus adding a fourth dimension to the experiment. If you remember from the original post, I was led to believe that older eggs made easier-to-peel eggs once they were hard-boiled. We'll finally get to put that premise to rest.
Two interesting items I've picked up on over the last four weeks are this: the shells feel more fragile, the older the egg, and the airspace at the wider end of the egg gets larger, the older the egg. Now, you may very well already know this, but for the sake of creating pleasant looking eggs for dishes such as Deviled Eggs, it's good to keep this in mind if you're looking for the perfectly shaped hard-boiled egg, too. Hopefully, as a result of my experiment, you'll be able to get perfectly peel-able and visually perfect eggs, no matter how old they are.
Without further ado, here are the results of week number four:
Control Group
6 cups of cold tap water
Time to come to boil: 11 minutes, 58 seconds
Time boiling: 1 min
Time sitting off heat: 11 minutes
Time cooled under cold water: 3 minutes
Control group ratings:
* Ease of peeling: 8
* Outer appearance: 8
* Texture: 10
* Taste: 10
Two of the eggs peeled like a complete dream, but the third one, which also brought down the appearance score, was a touch difficult, but not nearly as difficult as any of the other week's control groups. I should also mention that one of today's control group eggs actually cracked during the boiling process. While the gentle boil for one minute did nothing to make it any worse, this is significant to note since the eggshells over the four week test period have seemed to get thinner over time. This might pricking the end of the egg (no matter which method you use) make sense as it would relieve the air pressure and not cause the egg's shell to crack further.
Commercial Egg Cooker
Time in the egg cooker: ~17 minutes
Time cooled under cold water: 3 minutes
Water adjustment: - 1/2 tablespoon
Commercial Egg Cooker ratings:
* Ease of peeling: 10
* Outer appearance: 10
* Texture: 9
* Taste: 10
What can I say about the peeling and appearance of the Cuisinart Egg Cooker? It has been nearly flawless over the past four weeks. As impressive as that it, it isn't surprising. Cuisinart is a pretty solid brand and I would hope they wouldn't put out a uni-tasker device without it doing its one job nearly perfectly. The only two downsides I see to the egg cooker are the fact that you can only do seven eggs at once and I can get a slightly more tender egg when I do them using one of the other methods (in fact, ALL of the other methods) that I've been trying these past four weeks. That being said, the "set it and forget it" mentality certainly makes this device hugely desirable in many peoples' eyes.
Baking Soda In The Water
6 cups of cold tap water
1 teaspoon Arm & Hammer baking soda (sodium bicarbonate)
Time to come to boil: 11 minutes, 35 seconds
Time boiling: 1 min
Time sitting off heat: 11 minutes
Time cooled under cold water: 3 minutes
Baking Soda In The Water group ratings:
* Ease of peeling: 9
* Outer appearance: 9
* Texture: 10
* Taste: 10
The baking soda eggs this week were just shy of being a perfect peel and a perfect appearance. Overall, this method has done quite well, but other than the first week, has never achieved a consistently perfect score. That being said, the technique of adding a level teaspoon of baking soda to six cups of cold water drastically improves (at least when the eggs are fresher) the likelihood of easy-to-peel and easy-on-the-eyes hard-boiled eggs.
Salt In The Water and Egg Pricked
6 cups of cold tap water
2 tablespoons kosher salt (sodium chloride)
Time to come to boil: 11 minutes, 40 seconds
Time boiling: 1 min
Time sitting off heat: 11 minutes
Time cooled under cold water: 3 minutes
Salt In The Water and Egg Pricked group ratings:
* Ease of peeling: 10
* Outer appearance: 10
* Texture: 10
* Taste: 10
Interestingly, the "Salt & Prick" method has proven to be easy to peel from the beginning and nothing has changed this week. For the past three weeks, it has also yielded perfect-appearance eggs as well. This week, while I did give the appearance a 10, there was a notable blemish on one of the eggs; however, after checking the egg shell for signs of cooked egg white and discovering none, I determined that the blemish was caused by the age of the egg, rather than the white being peeled away with the egg shell. While I expected the air gap at the larger end of the egg to grow over time, I hadn't expected other areas of the egg to also show this feature.
So what is the great conclusion to all of this? If you want consistent results without having to worry about how they are cooked or for how long, go out and buy yourself a Cuisinart Egg Cooker. While you may have to tweak the amount of distilled water you add in order to get perfectly peel-able and delectable eggs, in the end, it does take all the guesswork out of the equation. If you don't want to waste $30 and wish to get great results out of the pan you already own, might I suggest the "salt & prick" method? I consulted with my friend and high school science teacher, Amy Waldfogle, who suggested this technique. Upon asking her why this method would work so well, she responded:
"what the salt does is it makes the water you're boiling in hypertonic to the solution in the eggs, which causes some of the water inside the egg membrane to leave - that shrinks the egg a little bit, separating it from the inside of the shell ... same thing that happens when the egg is older - it dehydrates a little"
and
"the inner shell membrane is 'selectively permeable' - that means some things (small molecules, things that are neutral) can pass through but others (big things, things with charges) can't. Salt (sodium chloride) and baking soda (sodium bicarbonate) are ionic compounds that dissociate when they dissolve in water - that means they become a bunch of ions floating around - they won't pass through the membrane"
and as a result
"water will move out of the egg into the pot because the natural order of things (entropy) favors equilibrium - everything having the same concentration - so since water is the only thing involved that can travel across the membrane, the egg will dehydrate"
So why prick the egg, too? In addition to allowing the air pressure to equalize inside and outside the egg (which prevents the egg from cracking during cooking), this also allows water to move into the egg during the cooking process and further separate the membrane from the shell. It's the same reason that the egg cooker (via steam) works so well, if slightly less effective.
So, there you have it. If you don't want to go out and buy yourself a dedicated egg cooker, simply prick the larger end of your eggs and add two tablespoons of kosher salt for every six cups of water in your pot. Interestingly, since the membrane in the egg only allows water to move back and forth, the salt in the water does not make the eggs salty, like it would with cooking pasta. Thus, if concerns about sodium intake are an issue, you can put those aside. In terms of the age of the eggs and how that affected the peeling results, generally, as the got older, they did become easier to peel (the control group at least). The second week was definitely a real pain to peel, and based on the original dozen that gave me such a hard time, I don't think that age is a definite indicator of success.
I hope this experiment has been as fun for you as it has been for me. Here's to many successful, easy-to-peel hard-boiled eggs!
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