Flour-Water Ratio in the Starter

Some sourdough starters are stiff doughs, similar to the type of pre-ferment called a biga. A stiff starter is sometimes referred to by its French name, levain. Others are looser batters, with the same consistency as a poolish. Thin starters are sometimes called barms. The two types are handled somewhat differently and yield slightly different results.

A thick, doughlike starter is relatively stable and does not need to be refreshed as often. It can be refrigerated without being refreshed for several days or even a week. Stiff starters favor the production of both lactic acid and acetic acid. Furthermore, the starter will produce more acetic acid under refrigeration than at room temperature. Often a baker will retard a stiff starter with the goal of increasing the ratio of acetic to lactic acid.