Poolish (or sponges) is made from equal parts flour and water, along with variable amount of either yeast or sourdough. Lately I've started using it for breads and pizza. It's worked particularly well for pizza. I took cues from Salvatore Kosta at Foorn. I also tried a Nancy Silverton formula. With a vast array of pre-ferments at hand, let them get into your world of mixes and bake!