Put the lukewarm beer in a bowl and dissolve the yeast in it. Stir in the rye flour and let stand in the refrigerator overnight.
The next day, except for the oat flakes, knead the remaining ingredients with the yeast mixture into a smooth dough. Divide into approx. 20 portions and shape each into a round shape. Brush the dough pieces with water and roll them in oat flakes. Spread on a greased tray and let rise to about twice the size. After a while preheat the oven to 275 ° C (or other highest temperature).
Put the rolls in the hot oven and at the same time lower it to 200 ° C. Bake for about 20 minutes, then take out the rolls and let them cool down.