and1/2 cups of flour

Flour is a powder produced by grinding cereal grains, legumes, or other starchy plant material. The most common flour is derived from wheat (Triticum aestivum), though flour can also be milled from rye, barley, corn, rice, oats, and numerous other sources. The grinding process separates the grain into its constituent parts: the bran (outer husk), germ (embryo), and endosperm (starchy center). All-purpose wheat flour, the most widely used variety, typically contains 10–12% protein and is milled from a blend of hard and soft wheat varieties. The fineness of the grind and protein content determine the flour's functional properties in baking and cooking—finer particles hydrate more readily, while higher protein content develops stronger gluten networks essential for bread-making.

Different flour types are classified by their protein content and extraction rate (the percentage of the grain retained after milling). Bread flour (12–14% protein) produces chewy, structured crumbs; cake flour (7–9% protein) yields tender, delicate textures; whole wheat flour retains all grain components and has a nutty flavor and coarser texture. Specialty flours include self-rising flour (with added leavening agents), pastry flour, and alternative grain flours like spelt, kamut, and einkorn.

Flour serves as the foundational ingredient in baked goods including bread, pastries, cakes, cookies, and biscuits, where its protein content and starch structure determine gluten development and final texture. It is also used as a thickening agent in sauces, gravies, and soups (via a roux—a flour-fat base), as a coating for fried foods, and as a binding component in batters and doughs. Different flour types are chosen based on the desired outcome: bread flour for yeast-risen loaves, cake flour for tender cakes, and whole wheat flour for added nutrition and earthy flavor. The hydration ratio, mixing method, and fermentation time all interact with flour's properties to determine the final product's structure, crumb, and flavor.