Stiffly beaten egg whites add lightness to baked goods such as angel food cake or waffles. Stiff egg whites can also be sweetened to make meringue. Unfortunately, several factors can prevent egg whites from attaining the necessary stiffness.
In order to whip into stiff peaks, egg whites must be free of yolk. Even a speck of yolk will keep egg whites from stiffening. In "The Gourmet Cookbook," authors Ruth Reichl, Zanne Early Stewart and John Willoughby advise separating eggs when they are cold, but beating them at room temperature.
Grease or Oil Contamination
The detrimental effect of egg yolks also holds for any other type of fat, including grease, oil or butter. These types of fat can contaminate your egg whites if your bowl or utensils are not immaculately clean. In "The Complete Idiot's Guide to Light Desserts," author Rose Reisman writes, "Avoid plastic bowls when beating egg whites because they can never be cleaned completely of grease residue."
Egg whites may take longer to beat up when they are wet and may lose stiffness too quickly. This can happen if there is water contaminating your bowl or utensils or simply because the day is humid or rainy.
Sugar Added Too Early
If making meringue, beat the egg whites to stiff peaks before adding the sugar. Introduce the sugar gradually only after the whites are beaten. If you add the sugar too early, the whites will stiffen very slowly.
Eggs Not Fresh
Older eggs start to stiffen more quickly than fresh eggs do, but they have trouble holding their peaks.