Baking is the process of heating gluten proteins within dough until they begin to form strong cross-links. Gas pressure within the dough builds under heat until the gluten strands split to form the familiar open network found when slicing a loaf.
Many ingredients may be used in order to create the dough used for bread and other baked goods. Eggs, oil and other fats are often used to create dough of different consistencies. Most dough recipes consist of a mixture of flour and water, as well as a leavening agent such as yeast or baking soda. Baking yeast break down and metabolize sugars in order to create alcohol and carbon dioxide. While heat from baking burns off the alcohol, the production of carbon dioxide is a necessary part of the rising process.
Dough can be kneaded and folded in order to create a network of stretchy proteins known as gluten. By applying heat, the dough is transformed into a crisp loaf that has many chambers created by trapped gas. A finished bread loaf may consist of as much as 80 percent empty space. Baking also serves to caramelize sugars on the outer portion of the dough, creating a thick hard crust.