Time for some math and science!!
As I started delving further into baking, I came across recipes that called for flours other than all-purpose. What? There are other flours besides all-purpose? I thought all-purpose was…well “all purpose”. Apparently not, and since as I stated previously that baking is a science, the type of flour you use really matters.
Types of Flour:
It’s important to understand what the different flours mean and how they’ll affect your end product so that the next time your cupcakes turn out more like hockey pucks, you’ll know why. There are tons of different types of flours from semolina to chickpea flour, however when it comes to cake baking you typically come across these 4 types: all-purpose, cake, pastry and self-rising. What do they all mean? Are they interchangeable?
Pardon me while I go a little Alton Brown on your asses… Flours are typically categorized by their hardness or softness, which refers to how much protein they contain. The harder the flour, the higher the protein, the more gluten they contain. Gluten is essentially like a network of chains that, in combination with other ingredients, creates the structure of your baked good. Additionally, things like kneading causes the formation of gluten strands which lead to a chewier texture. Great for bread, but not so much for cakes and the like, which is why you always read in recipes not to over-mix. On to the definitions…
As the name states, all-purpose (AP) flour can be used for a variety of purposes; from baking cakes and cookies, to pie crusts and breads. AP flour typically contains between 10 – 12% protein, and that amount varies between brands and even the geographic location from which the wheat is sourced. You can find AP flour both bleached and unbleached, and while they are interchangeable it will yield slightly different results.
Cake flour, which can contain anywhere from 6 – 8% protein, is a softer and more silky flour than AP and gives your baked goods a more velvety, fine textured crumb. One cup of cake flour can be substituted with either 1 cup, minus two tablespoons of AP flour OR with 3/4 cup sifted AP flour plus 2 tablespoons of cornstarch.
Pastry flour is similar to cake flour, but with a slightly higher protein content of 8 – 10%. To make two cups of pastry flour combine 1 1/3 cups of AP flour with 2/3 cup cake flour.
Self Rising Flour:
As the name may imply, self rising flour is a flour that contains a leavening agent. In this case that leavening agent is baking powder and some salt as well. It has a protein content of anywhere from 8 – 11%. Since the baking powder in self rising flour weakens over time, you can make your own by adding 1 ½ teaspoons baking powder and 1/4 teaspoon salt to 1 cup all-purpose flour.
Several months ago I took a one day cupcake baking class at the Institute of Culinary Education, and I came away with two very useful tips. The first was about how to properly measure flour, and the second is something I’ll cover in another post.
Over in Europe they weigh their ingredients; something I discovered when discussing baking with one of my best friends who happens to be English. We were exchanging recipes and I think she basically said “Cups? What the hell is that?” The truth of the matter is, we are doing it wrong and for the most accurate measurements you should be weighing your ingredients. However, since most recipes still call for cups (and converting from volume to weight requires too much effort), the best way to measure volume is by using the spoon or sprinkle methods. See, when you just shove your measuring cup into the bag or canister of flour you are essentially “packing” the flour in, and this can throw off your measurement by several ounces. If you’ve ever tried making the same cake recipe multiple times and yielded different results each time, this very well might have been the cause of your inconsistent results. So rather than dig out the flour out with your measuring cup, you want to either gently spoon the flour in and level off the top with a flat edge, or sprinkle it in (Tinkerbelle style) to the measuring cup with your fingers and level off the top with a flat edge.
There is TONS more to know about flour, but honestly do you really care about rates of liquid absorption based on bleaching methods? So while I’ve only just grazed the surface of the subject, this should be enough information to get you started.