Fermentation and Punching Down

Once dough is kneaded, it is usually allowed to rise until doubled or tripled in volume. The rising is caused by the fermentation of the yeast, which creates carbon dioxide. The gas is caught by the strands of gluten in the dough, which causes the dough to expand and gives the bread its pattern of air holes in the crumb. Most breads have only one rising before the dough is shaped, but some have as many as three. More risings result in a finer crumb. Most of the flavor of the eventual bread is formed during this first fermentation, not the fermentation that occurs after shaping, which is usually called “proofing”. Because most of the bread’s flavor develops during the first fermentation, it’s best to allow as much time as is practical. To keep the dough from rising too quickly, you can use very little yeast or increase the time. Of course if you’re using a starter, a long rising is less important because the starter provides flavor. If you’re making dough with sourdough starter, the dough can be allowed to rise at room temperature and it will still have plenty of time to develop flavor. Dough that is properly fermented will hold an indentation made with a fingertip.