How sourdough hydration works
Hydration is water as a percentage of flour. Water and flour contained in the starter must also be included in the calculation in order to obtain an accurate number.
Actual hydration = (water + starter water) ÷ (flour + starter flour) × 100
What hydration should I use?
65 to 70% is ideal for beginners. 75 to 80% needs strong flour, optimal bulk fermentation, and excellent shaping skills. Whole wheat and rye absorb more water, and must be added carefully while re-optimizing hydration and gluten development.
Does the starter count?
Yes. A 100% hydration starter is half flour, half water. 125 g of starter adds 62.5 g flour and 62.5 g water to your dough.
How much salt and starter?
Salt is usually 2 to 2.5% of total flour. Starter is commonly 15 to 25%; more starter ferments faster, less gives a longer but more flavourful rise.