Differing Methods

• Every method of combining ingredients serves a specific purpose. "Creaming" means vigorously beating a fat such as butter, usually combining it with sugar for cakes and cookies. "Whipping" uses a lightweight whisk or beater to introduce air into eggs or cream, to make a foam. "Beating" or "mixing" usually means combining the ingredients at medium speed to ensure they're well incorporated. "Folding" is the least forceful mixing method, usually used with fragile foams of cream or egg whites.

Basic Technique

• The point of folding is to preserve as much air as possible when combining light, frothy whipped cream or beaten egg whites with denser ingredients. The basic technique requires the baker to gently reach to the bottom of the bowl, scooping up the wet batter and folding it over the new addition. If it's done correctly, while turning the bowl and scraping the sides, the ingredients should mix thoroughly without excessive loss of air. That's important, because recipes that employ a folding technique usually rely on the trapped air for their lightness.

Adding a Foam

• In most cases, folding is called for when you're adding a foam of whipped cream or beaten egg whites to a relatively stiff batter. For example, it's common for chilled mousses, souffles and many cakes. Most bakers start by adding a quarter to a third of the foam to the mixing bowl, and simply stirring it in. This loosens the batter and makes it easier to work with. The remaining foam is usually added in thirds, gently folded into the batter until there are no visible streaks remaining.

Adding Dry Ingredients

• One exception to that rule is angel's food cake. For these, use a sweetened meringue as the base, and then fold in the flour and other dry ingredients. The basic folding motion is the same, though the technique is slightly different. Sprinkle about one-quarter of the dry ingredients lightly over the top of the egg whites, and fold them carefully until they're just incorporated. Repeat with the remaining three portions of the dry ingredients. There might still be some visible traces of dry flour in the batter, but they'll absorb moisture from the eggs as the cake bakes. It's more harmful to over-mix the cake, which prevents it from reaching its full height.