The amount of water in your starter does not just change its viscosity; it fundamentally alters its metabolism. By adjusting the water content, you steer the bacterial population to produce two distinct chemical profiles: the sharp, protective power of Acetic Acid, or the calming, enzymatic potential of Lactic Acid.

The true clock of sourdough is not measured in minutes, but in pH. The transformation of dough from a simple mixture of flour and water into a complex, digestible, and flavorful loaf is driven by acidification. Understanding the curve of this drop is the difference between a loaf that is bland and gummy, and one that sings.