Boil the cracked rye kernels and 470 g water in a pot for 10 minutes until all water is absorbed. Remove from the heat and let them cool off.
Put 900 g water in a bowl (I use the bowl from the mixer as the dough has to be kneaded for a long time). Dissolve the yeast in the water and add salt and sourdough. Mix it all together and add the rest of the ingredients as well as the kernels from the pot. Knead for 15 minutes.
Let the dough rest in the bowl for 15 minutes.
Butter up two loaf pans (30×10x10 cm) and divide the dough into the pans. Use a wet spatula to even out the top. Sprinkle with sesame seeds.
Let the bread rise to double size on the kitchen counter. It should take about an hour. Longer if you only use sourdough.
Preheat the oven to 250 degrees Celcius. Put a baking tray in the bottom of the oven.
Put the bread pans in the hot oven. Turn down the heat to 220 degrees Celsius and pour 2 dl of water into the baking tray to make steam in the oven. Bake the bread for approx. 1 hour and 15 minutes. Measure the temperature in the middle of the loaves, they should be 96 degrees Celcius in the middle in order to be done.
Let the bread rest in the pan for 5 minutes before turning them out on a wire rack to let them cool completely before cutting them.