Flour for Cakes

The two flours that I use most often for cakes are bleached cake flour and bleached all-purpose flour. Bleaching is critical for cakes made with unmelted butter because bleaching roughens the surface of the flour granules, helping them to keep the butter in suspension and improving gelatinization. When unbleached flour is used, cakes without center tubes will dip in the center soon after removal from the oven and some of the butter will have settled on the bottom of the cake, resulting in an unpleasant flavor and texture.