Cake flour contains less protein about 8% and more starch than all purpose flour and holds less water. It is low in gluten forming potential, is highly bleached and finely milled. It is made with soft wheat.
The low content of gluten help hold the evenly distributed air bubbles in the batter, makes light textured, tender cakes and biscuits.
Without cake flour, the cakes would not rise, or more likely they would rise and then collapse during baking and cooling.
By using cake flour, during late stages of baking, starch granules gelatinizes to set structure. The starch granules absorb water and swell then thicken batters, even as large amount of water and sugar added.
Rice flour is the most common substitute for wheat flour in cake recipes. If it is used alone in a recipe, however, rice flour will make for a gritty cake texture.
Grittiness can be eliminated by combining the rice flour with other flours.
Cake flour
