I will be referring to wheat flour only in this post, although “flour” can be used to describe a multitude of ground grains, nuts, etc.
Its a vital ingredient in bread. And cookies. And cakes, and…well you get the picture. Flour, especially from wheat, is a major component in many, many baked goods. But what many people do not realize is that all flours, unlike all men, are not created equal!
First of all, flour as we know it is made from the ground portion of the wheat kernel called the endosperm. It contains starch and gluten forming proteins that are activated upon hydration (adding water and other liquids) and physical manipulation (kneading, mixing, etc). The wheat kernel also contains two other components called the germ and the bran, but these two have been removed unless you are using “Whole Wheat” flour–get it? It’s the whole wheat kernel!
So since wheat is a crop, and it grown in the ground–dependent on soil and growing conditions, etc–it can vary greatly depending on what type of wheat was used to make the flour. Flours can even vary from brand to brand. Below is a list of a few of the commonly used flours and a description of each:
All Purpose Flour: This is a blend of hard spring wheat and soft winter wheat made to be used for just that–all purposes. It can be successfully used in cookies, cakes and breads. The protein content can vary from 10-12%
Bread Flour: These flours are typically made of hard wheat and their high protein content makes them suitable for yeasted products where a strong gluten complex is desirable. The protein can range from 12-13%
Cake and Pastry Flour: These are the lowest protein flours, made from a soft winter wheat. They are used in cakes and pastries where the lower protein keeps them tender. The protein usually ranges from 6-10%. **a side note: Cake flours are typically bleached and appear to be snow white. The bleaching lowers the pH of batters which improves texture by setting the proteins in the mix faster which results in a finer crumb.
Although they may all look alike, the properties of flours are very different with a majority of the difference lying in the protein content. All wheat flour contains gluten forming proteins that are formed when the flour is hydrated and manipulated, as stated above. Protein provides a structure for a baked good, but there are certain times when it is your friend or your foe. Higher protein flours are used in breads and other strong doughs where lots of gluten (protein) formation is good. Think of a strong balloon that needs to inflate. Where as lower protein flours are used in delicate pastries where a lot of protein would make the final product tough.
In addition, high protein flours absorb more liquid than low protein flours. Just remember, High Pro(tein)=High H2O. If you want to see this in action, take a cup of cake flour, a cup of all purpose, and a cup of bread flour and add about a cup of water to each. You will see how much less water the cake flour can take versus the bread flour with the all purpose right in between. It is for this reason, that if you make bread with all purpose flour, you may need to scale back on the liquid if the recipe had called for bread flour. Conversely, if you make a cake with all purpose flour, you may need more liquid if the recipe had called for cake flour. And that, my friends, is flour power.
Easy, right? It’s a piece of cake (flour)!!! Pun completely intended.