Mix the sourdough, yeast and 700-1000 ml of beer at room temperature. Mix whole wheat and rye flour with coriander, caraway seeds, nutmeg, anise and salt. Knead the yeast mixture, flour mixture, sunflower seeds and sesame seeds thoroughly (you can tell whether 700 ml of beer is enough or more). Cover and let rise in a warm place for 2 hours. Then shape 2 loaves of bread, brush with water and sprinkle with the oat flakes. Cut bread across or long. Preheat the oven to 230 degrees (no convection, preferably top and bottom heat), insert the bread and bake for 10 minutes, then reduce the temperature to 200 degrees and finish baking in 60-70 minutes. The bread is well baked if it sounds hollow when you knock on the loaf. Take out the bread and let it cool down.