Creaming

Creaming, in cooking, is the technique of blending ingredients &mdash; usually granulated sugar &mdash; together with a solid fat like shortening or butter. The technique is most often used in making cake batter or cookie dough. The dry ingredients are mixed or beaten with the fat until it becomes light and fluffy and increased in volume, due to the incorporation of tiny air bubbles. These air bubbles, locked into the semi-solid fat, remain in the final batter and expand as the item is baked, serving as a form of leavening agent.

Butter is the traditional fat for creaming, but vegetable shortening serves as a more effective leavener for a number of reasons. The low melting point of butter means it aerates best at temperatures cooler than most kitchens (18°C/65°F), while shortening works best at higher temperatures. Because of the coarser crystalline structure of its fat, butter allows larger air bubbles to form than shortening; large bubbles can rise in and escape from thin batters. Also, most shortening is made with preformed nitrogen bubbles and bubble-stabilizing emulsifiers, both of which enhance its leavening ability.

Creaming, in the laboratory sense, is the migration of a substance in an emulsion, under the influence of buoyancy, to the top of a sample while the particles of the substance remain separated, as compared to flocculation (where particles clump) or breaking (where particles coalesce).