In one sentence, describe what the following article is about:

Pay attention to the wording in the recipe when sifting your flour. The wording in a recipe affects how the flour is sifted. There is a difference between "1 cup flour, sifted" and "1 cup sifted flour."  If the recipe calls for "1 cup flour, sifted," measure the flour first. Then, transfer it to a bowl and sift. If the recipe calls for "1 cup sifted flour," sift a good portion of flour. Then, measure out however much you need for the recipe. You do not always need to sift flour. If flour has not been sitting in a bag too long, it may be light enough to simply use in a recipe. When flour is in a bag for awhile, however, it gets compact and needs to be sifted. If your bag of flour was squeezed into a cabinet, or had another item sitting on top of it, it's especially important to sift your flour. If your flour is not tightly compact, you may be able to skip the sifting process for some recipes. However, if you're making something that is meant to have a delicate texture, always sift your flour first. Recipes like angel food cake, for example, will require sifted flour. If you're going to roll out dough, or knead it, flour can help prevent the dough from sticking to a work surface. Sifted flour generally works better in this case, as it will have less clumps and spread more evenly. You should also sift flour if you're dusting flour over wax paper to roll out dough for sugar cookies.

Summary:
Figure out when to sift your flour. Sift flour that has been sitting in a bag for awhile. Make sure to sift flour for recipes with delicate textures. Sift flour over a work surface before you roll or knead dough.