Hydration percentage was the first piece of sourdough maths I learned to use properly. Before that, I was following recipes by feel and wondering why results varied loaf to loaf. Once I started weighing water as a percentage of flour weight, the variables became controllable.

Higher hydration is not inherently better — it produces a different loaf, with a different crumb structure and different handling requirements. The 80% open-crumb loaves you see on baking accounts require confident technique. Starting at 70% and building upwards is a more sensible path.

One thing the panel does not capture: whole-grain flours absorb significantly more water than white flour. If substituting 20% rye or wholemeal into a recipe, add 3–5% extra water and observe the difference in dough feel before adding more.