Crust

Crust is the exterior surface of a baked loaf, formed as the dough's surface dries out and browns under oven heat. Its color, thickness and texture come from a mix of factors, including how much steam was present early in the bake, how hot the oven was, and how long the loaf baked once uncovered.

A well-developed crust is more than a wrapper for the crumb: it provides most of the loaf's structural support right out of the oven, and the deep, sometimes almost burnished color that comes from sugars and proteins browning under high heat also contributes a lot of the flavor associated with a good sourdough loaf. Crust thickness and crispness are often adjusted by baking uncovered for longer, or at a slightly lower temperature, once the initial steamed phase is done.

A reliable oven thermometer helps confirm the oven is actually reaching the temperature a recipe assumes, since crust development depends heavily on real heat, not just the dial setting. A common mistake is pulling a loaf as soon as it looks done on the outside, when extending the bake by several more minutes without steam often deepens color and crispness without drying out the crumb underneath.