On hydration levels

The formulas require the hydration levels of the sourdough culture, the starter, and the final dough, i.e. the water to flour ratios. These rations are converted to absolute amounts of flour and water. This suggests that a certain hydration level results in the same consistency of the final dough irrespective of the type of flour used and other parameters. This is not true.

Different flours have different water absorption characteristics. For example, some flours remain somewhat stiff at a hydration level of say 60%, where other flours become more soft. Even the same type of flour may display a variation in water absorption characteristics over time. For example a bag of flour bought in January may display different water absorption charactertics compared to a bag bought in August, even though the brand may be the same.

Sourdough starters also become wetter the longer they ferment. Thus a starter that was prepared at a hydration of 50% (a 2:1 flour:water ratio), may have a different hydration level after fermentation. When a substantial amount of starter is used in the final dough, it will affect the hydration level of the final dough.

Similarly, the final dough gets wetter the longer it ferments. Thus the hydration of the final dough after fermenting and proofing is different from the hydration level after mixing.

Thus the formulas should be taken as relative formulas. For example, one could start with a hydration level of 60% and see (and feel) how the final dough works out. If the final dough after fermenting and proofing is too stiff, increase the hydration level in the formula. If the final dough is too soft, reduce the hydration levels in the formula.

Similarly, one could adjust other parameters too e.g. ferment the starter shorter or longer or use more or less starter. Obviously, such changes also lead to different fermentation times, different proofing times, and different breads.

Keywords: zuurdeeg, zuurdesem, sourdough, hydration level