Sourdough baking is part science, part intuition. Most baking apps treat it like a checklist — set a timer, follow the steps, done. But anyone who has baked sourdough knows it doesn’t work that way.

Bulk fermentation time depends on your starter’s activity, your dough temperature, your kitchen’s ambient temperature, and a dozen other factors. A 4-hour bulk at 78°F is a completely different beast from a 4-hour bulk at 68°F.