1st stage: Stir through flour and water, cover well and stand for 24 hours at approx. 20 °C.
2nd stage: Mix into the first batch (stage 1). The 1st batch already smells sour. Cover and stand repeatedly for 24 hours at 20 °C.
Stage 3: Stir this mixture with the previous mixes (Stage 1 and Stage 2) and stand again, covered, at 20 °C for 24 hours.
The sourdough is now ready and should be baked quickly. There are 800 g of sourdough, 2×50 g of which should be taken away and frozen for the next starter. With 700 g sourdough is now baked our rye sourdough bread (-> separate recipe).