Sponge can be refrigerated for 1 week or frozen for up to 3 months. Use it to make Ciabatta, Peasant Bread, and Olive-Filled Rolls.
In the bowl of an electric mixer, combine 1/4 cup warm water and yeast. Let stand until yeast is creamy, about 10 minutes. Add remaining water and flour; mix on low speed, 2 minutes. It will be the consistency of a wet dough.
Place the dough in a lightly oiled bowl. Cover; let stand at room temperature for 24 hours. Bring to room temperature before using.