In many recipes, the word "sifted" can cause confusion—should the flour be sifted, then measured or measured, then sifted? Can you even sift ingredients without a sifter? To answer these questions, let's take a deeper look at the sifting process.
Why We Sift Flour
Before milled flour became readily commercially available, bakers and cooks sifted flour to separate the flour from the chaff (corn or seed husk) and debris. Today's refined flour won't contain these unwanted elements, so if a modern recipe calls for sifted flour, it probably means that the recipe requires a more aerated flour without any lumps. For example, delicate treats like angel food cake get their fine, light crumb from sifted cake flour. If the recipe calls for sifting flour with another ingredient—such as cocoa powder—that process both aerates and combines the ingredients.
When to Sift Flour
The most important thing to remember is that unless the recipe specifically tells you to sift flour, don't sift it. Modern flour processors sift flour many times before it leaves the plant, so home bakers rarely need to repeat the process. Flour sold these days is ready to use right from the bag.
If your recipe mentions sifted flour in the ingredient list, then you might wonder whether you should sift or measure first. The answer to this question usually depends on the recipe's grammar: If the recipe calls for "2 cups sifted flour," you should sift the flour into a bowl, then measure it. However, if the recipe calls for "2 cups flour, sifted," you should measure the flour first, then sift it. Before tackling any home cooking, it is important you understand how to read a recipe.
How to Sift Flour
Obviously, a sifter—basically a cup with a strainer at the base—is the ideal tool, but if you don't have one, you can use a strainer. Hold a fine-mesh strainer (or sieve) over a bowl, add the flour to the strainer, and gently tap the side repeatedly until all of the flour has passed through the strainer. You may need to help the last little bit get through the holes—just move it around with a spoon.
Whether or not you sift the flour, you should first ensure that you've measured it correctly. Beautiful, fluffy flour won't help your recipe if you have added too much or too little of it. In the baking world, an inaccurate flour measurement will ruin a recipe.
There are incorrect and correct ways of measuring flour. For reliable results every time, you should spoon the flour directly into the measuring cup, mound it on top, and then level it off with the side of a knife. No scooping, tapping, or packing down.