Easy Egg Separation

Follow these simple steps for separating whites and yolks.

Most of the time when we’re separating eggs, if a stray bit of yolk finds its way into the whites, we scoop it out with the eggshell. We’ve always wondered why that works so well, so we phoned our trusty science editor. He explained that the shell membrane is coated with the protein keratin, which has an affinity for the protein that is in yolks. When you try the same trick with a metal spoon, he continued, the yolk usually skitters to the other side of the bowl. The yolk contains water and lipoproteins that, in nonscientific terms, just don’t like metal. Some experts caution against using the eggshell to “de-yolk,” as it could contaminate the whites with salmonella. But if the whites will be heated to more than 165 degrees, don’t worry about the bacteria. Some recipes depends entirely on whipped egg whites for lift, and here even the barest trace of yolk spells ruin, so we are extra careful. When we make cakes or meringues, we separate the eggs with a three-bowl method. Should a yolk break, it won’t spoil the entire bowl of whites.