Transforming Chewy Dough into Crisp Bread

In principle, baking bread involves gelatinizing the starch in the dough. When it is heated, the tough, gelatinized structure of the crumbs in the dough change to the texture that is the hallmark of fresh-baked bread. The nature of the crumbs has changed from being tough to being spongy and solid. How closely they are packed together depends on the leavening agent used, how long the dough is allowed to rise, and the gluten content of the flour. At the same time, the crust has become crisp and crunchy.