Many velvety, light textured recipes such as souffle, meringues, or chocolate mousse call for whipped egg whites. Egg whites must be completely uncontaminated by yolk in order to whip up properly. It can be very frustrating to work with contaminated whites when after many minutes of work you still have liquid, and must start all over again separating the eggs.
To efficiently bring egg whites to soft or firm peak stage, it is important to follow some basic rules. First, make sure your eggs are at room temperature. If you are in a hurry, you can speed the process by immersing them in tepid water for about 10 minutes. Use a clean, dry bowl to whip the eggs in, as any specks of dust, grease, or lint might prevent thickening. Finally, wash and dry your whipping instrument as well, for the same reason.
When separating your eggs, be very careful not to break any yolk into the egg whites. The easiest way to forego contamination and waste is to practice the isolation method by following these simple steps:
Collect three bowls, and arrange them close to each other. These are your yolk bowl, white bowl, and crack bowl. Hold your eggs separately in another container.
Crack your first egg on a flat surface and pry the shell in two with your thumbs. Pour the contents of the egg into your hand and let the white slip through your fingers, keeping hold of the yolk. Place the yolk into the yolk bowl. Put down the shell and then pour the white from the crack bowl into the white bowl. Repeat this with all of the eggs.
The advantage to doing this is if you do happen to break a yolk, you have only wasted one egg into the crack bowl, and not into the entire pool of whites you so carefully separated out before.
Whip your eggs with a whisk, egg beater, or in a mixer with a whisk attachment. It takes quite a while to do it by hand, but you do not risk over whipping as much. Test for firmness by dipping the top of your mixing tool into the eggs, and then lift it out and turn it right side up. Soft peaks will form a curl and slump over.
Firm peaks will stand up stiffly and have a nearly chalky texture.
If you over whip your eggs, they will revert to liquid stage. Sometimes this can be saved by adding another white and whisking some more.
Separating and whipping eggs successfully is a useful skill in the kitchen, and greatly expands the range of recipes you can experiment with.