Mix 300 g whole wheat flour, oat flakes, pumpkin seeds, flax seeds, wheat grains and wheat sourdough with the 500 ml water in a large bowl for about 10 minutes. Let rest covered for 24 hours at room temperature.
The next day:
Add the remaining ingredients and stir well for about 10 minutes.
Now you can take away 175 g of dough as a new item and store it in a glass with a screw cap in the refrigerator for up to 2 months.
Put the dough in a loaf pan lined with baking paper or greased (approx. 25 x 14.5 x7 cm) and let rise until the dough has reached the edge of the pan. This can take 1 - 1.5 hours.
Bake in the preheated oven on the 2nd rack from the bottom at 200 ° C top and bottom heat for about 90 minutes (varies by 10 - 15 minutes, depending on the oven).
Steam when pushed in and let off steam after 10 minutes.
The bread is ready if it sounds hollow when you tap the underside of the loaf with your knuckles, but it should definitely be juicy.