What is a "sponge" in bread making?

In bread making, a "sponge" is a type of preferment that is typically made with flour, water, and yeast. This mixture is allowed to ferment for a certain period before being incorporated into the final dough. The purpose of using a sponge is to develop flavor and improve the dough's structure by allowing the yeast to become active and produce gas, which creates a light and airy texture in the final bread. By incorporating a sponge, bakers enhance the fermentation process, leading to a better rise and ultimately a more flavorful bread.

Using a sponge helps in achieving a more complex flavor profile compared to using straight dough methods. This technique also often improves the dough's extensibility and strength.