How does the bread become spongy?

Bread becomes spongy through a process called fermentation, which is driven by yeast or other leavening agents. Here's a simplified explanation of how it works:

Mixing: The process begins with mixing together flour, water, yeast, and sometimes other ingredients like salt and sugar. This forms a dough.

Kneading: Kneading the dough develops its gluten structure. Gluten is a network of proteins that gives bread its elasticity and helps it trap gas bubbles produced during fermentation.

Fermentation: Once the dough is mixed and kneaded, it is left to ferment. During fermentation, the yeast consumes sugars in the dough and produces carbon dioxide gas and alcohol as byproducts. This gas gets trapped in the gluten network, causing the dough to rise and become airy.

Proofing: After fermentation, the dough is shaped into loaves or other desired forms and allowed to undergo a second rise, known as proofing. During proofing, the yeast continues to produce gas, further expanding the dough and giving it a spongy texture.

Baking: Finally, the proofed dough is baked in an oven. The heat causes the yeast to die and the alcohol to evaporate, leaving behind the spongy structure created by the gas bubbles trapped in the gluten network. The crust of the bread forms as the exterior dries and browns due to Maillard reactions.

The precise texture of the bread can be influenced by factors such as the type of flour used, the hydration level of the dough, the fermentation time, and the baking temperature.