Pour approx. 40 ° C warm water over the grains and meal or cereal flakes for the source piece, mix the mixture and let it steep for 12 hours.
The next day, mix the remaining ingredients with the source piece and mix slowly in the food processor (or by hand). In the machine this takes about 7–8 minutes, with the hand a little longer. Then knead for another 2 minutes until the dough comes off the bowl (or from the hand).
Shape into a ball and leave covered for 60 minutes on a board or in a Weidling.
Work the dough into an elongated loaf, place in an oiled loaf pan and let rest for another 60 minutes at room temperature.
Preheat the oven to 250 ° C, slide the loaf pan into the oven and bake at 250 ° C for 10–15 minutes. Then reduce the temperature to 230 ° C and bake for another 45 minutes. The finished bread should have a core temperature of 95–97 ° C.