I have been baking whole grain bread for years, and when living in Denmark in the 70s, I fell in love with Struer brød, which was basically whole-grain rye kernels held together with sourdough and whole-grain rye flour and a bit of salt. The sourdough was usually produced with potato water and flour, I poured boiling water over the rye kernels as previously described, and assembling the bread was generally quite a sticky heavy mess. One thing that they did in Danish recipes was suggest weighting down the top of the bread and placing a pan of hot water at the bottom of the oven. I would wrap the bread in a tea towel after removing it from the pan if I wanted a softer crust. Since that time I have modified my standard recipe because I have only myself to bake for, so I have combined different breads. I generally use rye or spelt whole kernels, soaked as described, sourdough or yeast, whole-grain flours whether rye or spelt or both, and sometimes sunflower seeds, flax seeds and sometimes anise for a lovely aroma when toasted. Fulkornbrot there's always heavier, more nutrient-dense, and can be a meal in itself with some cheese, boiled egg, or pickled herring. It is the foundation of Danish smørbrød. I have enjoyed experimenting over the years, and always appreciated heavier bread after a childhood eating German or Lithuanian breads. Have fun with it.