Fermentation, or Rising

Fermentation is the stage during which the dough is set aside for the yeast cells to produce carbon dioxide, which diffuses into the air pockets, slowly inflates them, and thus raises the dough. This gentle stretching action continues the process of gluten orientation and development, as does the oxidizing effect of other yeast by-products, which continue to help the glutenin molecules to link up end-to-end. As a result, even initially wet, barely cohesive doughs become more manageable after fermentation.