All Purpose Flour vs Cake Flour
If you are just a beginner in baking, you are bound to be muddled when you come across recipes that call specifically for cake flour for most of us generally believe that the all purpose flour can be used for most baking. However, the kind of flour you use for baking cakes, pastries and bread does make a huge difference to the end results.
The most significant difference between cake and all purpose flour is the amount of protein content in it. The protein content in the flour influences the amount of gluten created while kneading and leavening the flour. Glutens are nothing but amino acid strands that make the flour more elastic or less elastic when flour is mixed with water and kneaded since they are responsible for holding the air or gas that is created within the dough while kneading and leavening the flour. In other words, gluten is the element responsible for making the end result either tough as in breads or airy and crumbly as in cakes or pastries. Typically, cake flour consists of 7-8% of protein content while general all purpose flour consists of 11-12% of protein content.
Climate also influence the amount of protein content in wheat and typically, in the United States, all purpose flour made from wheat grown in Southern states have a protein content of just 7.5-9.5% while all purpose flour made from wheat grown in Northern states have a protein content of 11-12%.
Another difference is that cake flour is called ‘weak’ flour as its chief ingredient is soft wheat whereas all purpose flour is a combination of both hard and soft wheat. All purpose flour cannot be called ‘strong’ flour but falls somewhere between strong and weak as it requires something like bread flour that contains more hard wheat to be called strong flour.
Also, all purpose flour is not as finely ground as cake flour due to which there is a difference in the texture of both the flours. Some chefs and bakers say that cake flour is chlorinated to make it more acidic and absorb water quickly in order to make the cake rise and set well.
If a recipe asks for cake flour specifically, it is better not to substitute with any other flour but general substitution formula for 1 cup of cake flour is equivalent to 1 cup of all purpose flour minus two tablespoons. Some also say you can add about 2 tablespoons of cornstarch to the all purpose flour.
Summary:
1.The major difference between the both flours is the amount of protein present in them that influences the gluten or elastic quality of the flour. Cake flour has low protein content, around 7-8% while all purpose flour has around 11-12%.
2.Cake flour is made from soft wheat whereas all purpose flour is a combination of both hard and soft wheat.
3.Cake flour is finely ground and chlorinated sometimes as against all purpose flour.