Poolish

Developed in Poland in the 1840s and later adapted for use by the French and Viennese, a poolish uses equal parts water and flour (that is 100 percent flour and 100 percent water) and no salt. It can be fermented for as little as 4 hours or for long as 18 hours, depending on the amount of yeast (a small amount of yeast requires a longer period of fermentation than a large amount). Poolish is now used worldwide.