How do flour, water, and leavening agents affect baked goods?

Flour, water, and leavening agents are the fundamental ingredients that determine the appearance, texture, and flavor of most baked goods.1

• Flour: When mixed with water, the proteins in flour form gluten, an elastic network that provides the structural foundation for dough. The protein content of the flour dictates this structure: high-protein "hard" wheats create strong networks suitable for breads, while low-protein "soft" wheats produce the delicate, crumbly textures found in cakes and cookies.234
• Water: Beyond acting as a medium for mixing, water is essential for hydrating gluten to form the cellular structure of the dough. It enables yeast to metabolize sugars, facilitates the chemical reactions of leavening agents, and allows starch to gelatinize during baking.3
• Leavening Agents: These substances cause doughs and batters to expand by releasing gases—such as air, steam, or carbon dioxide—which are trapped by the gluten network. Whether through biological fermentation (yeast) or chemical reactions (baking powder/soda), these agents create the porous, light structure characteristic of finished bakery products.5