Flour–the key ingredient to any baked good. Learn the difference between bleached and unbleached and discover the importance of protein content.
Flour is classified by its protein content, which is determined by the type of wheat. For instance, a hard winter wheat is about 10 to 13 percent protein and has a slight granular texture. Wheat with a smaller protein content is softer and finer.
High protein flours, like bread flour, are recommended for yeasted products because they require a lot of structural support. The high protein content provides a greater potential for the formation of gluten. “Gluten forms elastic sheets in dough that expand with the gas released by the yeast yet are sturdy enough to prevent that gas form escaping, so the dough doesn’t deflate.”
Low protein flours are used for baked goods that are chemically leavened with baking soda or baking powder. While yeast is strong enough to force the naturally resistant gluten sheets to expand, chemical leaveners are weaker causing the baked good to fall flat.
Other factors affecting the behavior and taste of flour include milling, processing, and bleaching, which I will discuss.
All-Purpose Flour: Bleached vs. Unbleached
This is the baker’s go-to flour–always in the pantry and ready to use. This flour has a protein content of about 10 to 12 percent. The two types of all-purpose flour are unbleached and bleached. So what is the difference?
In short, unbleached all-purpose flour is less processed and aged naturally while bleached flour uses either benzoyl peroxide or some type of chlorine to accelerate the flour’s aging process. Because there is a growing popularity in less processed foods, unbleached flour is making a comeback.
Is there a taste difference? Unless you have a very sensitive palette, there is no difference in taste. In fact, most of the difference are visual…
Unbleached flour is off white resulting in a beige cookie. It also has a slightly higher protein content which can provide a denser texture. Bleached flour is bright white resulting in a light colored cookie. It’s protein content is slightly smaller which can cause spreading in cookies and muffins, but no difference in taste.
I prefer unbleached flour, the difference in color does not bother me and I feel better knowing my ingredients aren’t filled with harsh chemicals. Remember that not all flours are made the same, the chart below provides the protein content for various brands of unbleached all-purpose flour. This is helpful if your recipe calls for a specific level of protein.
Protein Content of Unbleached All-Purpose Flour
As I previously mentioned, bread flour has a high protein content–above 12 percent. The protein provides structural support for the formation of gluten. This allows for a sturdy dough with “good flavor, chewy texture, and a crisp crust.” If you have a bread machine, bread flour is highly recommended. However, there are recipes that do not require bread flour, like my no-knead artisan bread.
Cake flour has a very low protein content, about 6 to 8 percent. This is why it has a superfine texture. It “guarantees delicate, fine-crumbed cakes and light, airy biscuits.” If you are in a bind, using a low protein all purpose flour makes only a subtle change in the cake’s texture.
Whole Wheat Flour
Made from the entire wheat berry, this flour is more perishable because it contains the wheat germ. (White flours ground only the endosperm, the heart of the berry.) If you are not planning on using the whole bag within a month, store it in the freezer.
This diagram of a kernel of wheat describes its three parts–the outer bran layer, the germ, and the endosperm.
Source: Baking Illustrated