The main ingredient in traditional bread is flour, typically made from wheat. Flour provides the essential starches and proteins necessary for bread-making. The proteins in flour, particularly gluten, play a crucial role in giving bread its structure, elasticity, and chewiness. Water is also necessary to activate the gluten and hydrate the flour, while yeast is often added to facilitate fermentation, causing the dough to rise. Other ingredients, like salt and sugar, can enhance flavor and texture, but the fundamental building block remains the flour.