All-purpose flour, bread flour, cake flour, pastry flour -- there are a ton of different flours out there, and each one serves a very specific purpose. The trick is not only knowing when to use them (fortunately their names are good indications), but also knowing when and why they might be crucial, and when they may be substituted. "Are cakes that much better when they're made with cake flour?" you may be wondering. "Does a yeast bread come out better with bread flour instead of all-purpose?" Allow us to give you the low-down on flour.
First, for the purposes of this post, we're talking about only wheat flour. We're not going into garbanzo flour, nor are we considering rice flour. We're sticking with wheat on this one. With that in mind, there are two different types of wheat used in wheat flour: hard and soft. The difference lies in the protein content, with hard wheat containing a higher level of protein than soft. Also, wheat is milled and processed in slightly varying ways to create the different flours. For example, whole-wheat flour will be darker in color than all-purpose flour because it contains the whole kernel (the bran, germ and endosperm), rather than just the endosperm (the center of the wheat kernel).
Once you've understood the root of the differences, you can start to comprehend the advantages and disadvantages of different flours. Here are eight types of flours, and when you should use them: