Flour is a powder made by grinding grain, most commonly wheat. When wheat kernels are crushed into a fine, soft powder, you get the white or tan flour used to make bread, cakes, cookies, and pasta. Without flour, you couldn't have pizza crust, birthday cake, or fresh-baked cookies.

For thousands of years, people have ground grain between heavy stones to make flour. Today, machines do this work in huge mills, but the basic idea remains the same: crush the grain until it becomes powder. Different grains produce different types of flour. Wheat flour is most common, but you can also find rice flour, corn flour, rye flour, and others.

When you mix flour with water, something interesting happens: proteins in the flour can form gluten, which creates a stretchy, elastic texture. That's why bread dough can be kneaded and shaped. It's also why bakers measure flour carefully: too much makes baked goods tough and dry, while too little can make them fall apart.