Also Known As Bleached, Chlorinated Flour, Enriched Cake Flour or Soft Wheat Flour.
What is Cake Flour?
Cake flour is a powder made from grinding soft red winter wheat or soft white wheat. The bran and germ are removed leaving only the starch endosperm. Cake flour has a low protein content of 8% and high carbohydrate content. Cake flour is typically treated with chlorine gas and benzoyl peroxide. White flour is required by the FDA to be enriched with thiamin, riboflavin, niacin, folic acid, and iron.
Wheat is produced globally. Soft Red Winter Wheat is typically grown in the Eastern United States. Soft White Wheat is primarily grown in the Northwest United States. The wheat is harvested and delivered to flour mills to grind into flour.
Cake flour has a lower protein content (6-8%), low ash content and fine particle size which makes it ideal for high-ratio cakes. Low protein is necessary to keep the cake tender, it prevents an over-developed gluten matrix that would make the cake tough and have low volume. Cake flour is chlorinated to alter the starch molecules to allow for greater absorption and strength to carry the heavy sugar load of a cake batter. This will result in higher volume, finer grain, and a more tender cake than if the cake was prepared using a flour that had not been chlorinated. Cake flour is typically also treated with benzoyl peroxide to make the flour bright white in color. Bleached cake flour has a lower pH than untreated flour. Optimum pH of bleached cake flours is in the 4.6 to 5.1 range. Untreated flours typically have a pH of 5.8 to 6.1.
Cake flour is composed of moisture (12%), protein (8%), fat (1%), carbohydrates (75%), and ash (0.4%).
Cake flour should be used as the sole source of flour in high-ratio cake formulations. The flour should be added near the end of mixing to prevent over-development of the gluten matrix. It can be blended with a mid-range protein flour for cookie and brownie-type applications. If used alone in cookies it will reduce the cookie spread.
Wheat flour is very low in saturated fat, cholesterol, and sodium. When it is enriched, as required by law in the U.S., it is a good source of folic acid, iron, B vitamins, as well as complex carbohydrates.