Foaming Egg Whites
To foam egg whites, you must first ensure that they are pure egg whites, with no bits of yolk in them. The yolks contain fat, and fat will inhibit the foaming, and do nothing to help you.
If possible, use a copper bowl to whip the egg whites. Copper produces a reaction in the egg whites, which allows them to foam to a greater volume and stability. Copper bowls are also very expensive, and a pain to take care of, so if you don’t have one, it’s not a big deal.
For greatest volume, the egg whites should be at room temperature when foaming, not cold.
If whipping by hand, rest the bowl on a damp, folded towel, to keep it in place. If using a mixer, run the machine at medium speed to start, to allow the whites to foam smoothly.
There are three stages of doneness for foamed egg whites: soft peak, medium peak, and stiff peak. To test, scoop up some of the foam with a whisk, and see how the whites hang from the whisk.
At soft peak, you will see a droopy, rounded peak, that slowly slides off the whisk.
At medium peak, you will have a rounded peak that is more stable than soft peak, and will not slide as much. Now is the time to add sugar or other flavorings, if using them.
At stiff peak, the egg whites will hang from the whisk in a stiff, stable peak. At this point, the surface of the foam should still be moist and glossy. Do not overbeat, as doing so will cause the whites to turn dry and lose elasticity.
