Originally Posted by Alvina
I was told that cake flour = 20% corn starch + 80% plain flour.
So far I have tried this formula for a cake recipe and it turns out great.
Hope it helps!
For me, cake flour is a white/brown or wholemeal flour with raising agent added in the mill - otherwise known as Self-rising/Raising flour. The added rising/raising agent will be baking powder - a chemical reagent activated by moisture and heat to produce carbon dioxide.
As the gas (CO2) expands, due to heat it "raises" the mixture, and the cake is fixed in shape when the proteins of the flour and egg coagulate (or set) due to the applied heat. Other gases may be present, and in particular air, incorporated during the creaming of fat and sugar or whisking of egg yolks and sugar of egg whites. Air will expand on the application of heat in the same way as carbon dioxide.
A 20% corn starch + 80% plain flour will need to be raised either by egg whites, a very well whipped combination of eggs and powdered sugar or a chemical reagent like baking powder, added to the flours, to produce a cake. So what cake are you making - what is your recipe with this combination of flours?
Quite frankly, I cannot concieve of a cake which can be baked without some form of leavening - egg whites, egg yolk and sugar mousse or a chemical reagent. Do let us know how you do it!