Bread crust is the outer layer of a loaf of bread that forms during the baking process. It is typically firmer and darker than the soft interior, known as the crumb. The crust develops through the Maillard reaction, which occurs when sugars and proteins in the dough react to heat, creating flavor and texture. The thickness and texture of the crust can vary depending on the type of bread, such as sourdough, baguette, or whole wheat. A well-baked crust can enhance the overall taste and experience of eating bread, providing a satisfying contrast to the soft inside.