Well, we all know that — off the shelf in the supermarket. But “picking” your flour isn’t that simple, once you start reading the bags. They no longer say just White and Brown, and you may have to stop and think about what you really need. Even all-purpose flour may come in bleached and unbleached, enriched, presifted, self-rising . . . Let’s look at what all this means.
First off, all-purpose white flour is the handiest kind to have around. (Whole wheat is healthier, but you can’t just substitute it for white, especially in pastry. If you want to bake healthier breads and biscuits, you might want to start by using whole wheat flour to replace half the white flour.) Bleached flour has been whitened, sometimes with actual chlorine — this and other bleaching processes can affect the gluten. “Enriched” flour has added nutrients, but they’re only replacements for the ones lost during the processing — and not even all the nutrients get replaced.
Some recipes may call for cake flour, which is specially treated to hold sugar and liquid. The Joy of Cooking says “in emergencies” you can use a cup of all-purpose, less two tablespoons, for every cup of cake flour. You may not get the results you wanted — and if you do it the other way around, substituting cake flour for all-purpose, you probably won’t.
Another kind of flour you probably don’t need — unless you use flour only for biscuits, cookies, and quick breads — is self-rising. This already contains leavening (ingredients, like baking powder, to make the dough rise). Though of course you wouldn’t know that to look at it. I don’t think I could ever bring myself to trust self-rising flour, and would probably end up adding baking powder anyway. Besides, it’s pointless if you’re making yeast bread, or just using your flour to thicken a sauce or coat some meat.
Speaking of thickening, a specialty flour you probably should keep on hand is instant or quick-blending flour. This is formulated to blend more easily with liquid, and you can use it in place of cornstarch to thicken sauces, soups, and gravies. It also lets you make white sauce without having to melt fat first and blending the flour with it. Stir a little of this into milk or clear broth, add seasoning, and you no longer have any need for canned cream of mushroom soup.
All-purpose, blending, whole wheat if you want, and cake if the recipe calls for it — and your flours are all picked.