Q: Dear Chef,
My sister eats egg whites and throws away the yolks. She says it’s the low-fat, low-cholesterol way to go. Personally, I’m astounded at this, as the yolk seems, to me, the only thing in the egg worth eating. Is my sister crazy, or is she onto something?
Also, sometimes when I eat eggs I get the sulfur burps. What’s up with that? And what’s your advice on the best way to hard-boil an egg?
A: I agree with you, YF, your sister’s egg white habit is odd, although she’s hardly alone. I used to work with a weightlifter guy who peeled eggs on coffee break and ate the whites. When I asked for his yolks he looked at me funny.
But as you point out, all of the flavor is in the yolk. The whites have interesting culinary properties—you can beat them stiff, for example. But beyond adding body, the whites don’t have much more to offer other than sulfur burps. Those decadently satisfying yolks, on the other hand, are why we like eggs. If you don’t want to eat yolk, leave the egg intact and eat something else.
As for the sulfur, according to Exploratorium.com (the website of a really cool science museum in San Francisco), “When eggs are subjected to excessive heat, the sulfur and hydrogen in the egg white combine to form hydrogen-sulfide gas." Further, "When the gas reacts with iron present in the egg yolk, a gray-green film forms where the white and the yolk contact each other.”
As for boiling eggs, I’ve had the best luck by putting them in cold water in a pot, bringing the pot to a boil, and turning off the heat. You can either let them sit until the water has cooled, or wait 20 minutes and then plunge the eggs in cold water, which will make them easier to peel.