A couple of years ago, I wrote about how we like our fried eggs. We have different preferences about how well done the white or yolk should be so that frying eggs in this household can be a risky business — do it wrong and you’ll have uneaten eggs.
We have different preferences with our boiled eggs too. Sam likes fully hard-boiled eggs. Speedy prefers the white to be firm and the yolk barely wet at the center. I like my egg white to be barely firm and the yolk completely runny, and I like to sprinkle spices (salt, pepper and cayenne are favorites) on my egg. Alex is not fond of boiled eggs.
While boiling eggs is perceived to be the second simplest thing to do in the kitchen (next to boiling water), there is actually a more-or-less scientific way to achieve the balance of rawness and doneness even though you can’t see the egg through the shell while you’re boiling it — you measure the time beginning on the moment that the water starts to boil. So, there is a one-minute egg (barely set white and totally runny yolk), a three-minute egg, a five-minute egg and a seven-minute egg (fully hard-boiled). If you boil the eggs for too long, a sulfuric-smelling greenish-grayish layer forms between the yolk and the white. Some say it’s not a health hazard but who likes gray-green eggs?
But how you count the time depends on a lot of factors. Eggs vary in sizes from small to extra-large. A small egg boiled for one minute will be more cooked than a large egg boiled for the same length of time. And that’s just one factor. There are more.
Do you turn off the heat after the water boils? Do you use an electric stove with coils (switching off the heat won’t immediately “turn off” the heat as the coils take time to cool)? Does your pan retain heat longer (for instance, ceramic pots) after it is taken off the stove? Lots of variables in other words. But if you’re familiar with how your stove works and the pan that you normally use for boiling eggs, counting the time is not such a hit-and-miss thing.
Some cooks add their eggs to already simmering water. I like to start with cold water. I put the eggs in a pan, pour in enough water to cover the eggs by an inch, then I set the pan on the stove. When the water boils, I set the stove to its lowest setting and cover than pan. Then I start counting the minutes.
What about dousing the boiled eggs in cold water? Is that necessary? For me, that makes sense. Inside the shell, the egg is still very, very hot and the white and yolk will continue to cook in the residual heat unless the cooking process is stopped by either dumping the eggs in a bowl of cold water or giving them a bath under the tap.
What about peeling the eggs? Why do the egg white sometimes stick to the shell? It has to do with the age and acidity of the egg. A very fresh egg is more acidic and… here’s a scientific explanation from Wired.
“The best guarantee of easy peeling is to use old eggs!” wrote Harold McGee, in his monster 800-page tome, On Food and Cooking: The Science and Lore of the Kitchen. “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.”
The USDA provides a complementary explanation more focused on the air cell, which you can see in the schematic, sitting between the outer and inner shell membranes.
“As the contents of the egg contracts and the air cell enlarges, the shell becomes easier to peel,” the USDA Shell Eggs from Farm to Table fact sheet states. “For this reason, older eggs make better candidates for hard cooking…”
So, next time you cook something that calls for boiled eggs, consider all of the above before putting your eggs into the pan. All of that can make a difference on how your boiled eggs turn out.