Pre-ferment: Put the wholemeal spelt flour, seeds, crumbled yeast and lukewarm buttermilk, into a mixing bowl and mix into a dough using a wooden spoon. Cover and leave to rise for 20 minutes.
Yeast dough: Knead the pre-ferment and the remaining ingredients with a handheld mixer (dough hook) slowly for four minutes and then quickly for 30 seconds until a smooth dough forms.
Cover and leave to rest for another 45 minutes.
Form the yeast dough into a round bread loaf, sprinkle the top with wholemeal rye flour and place on a baking tray lined with baking paper. Cut crosswise and leave covered for another 20 minutes in a warm place.
Preheat oven to 250 °C (top/bottom heat).
Place a heat-resistant tray holding hot water on the bottom of the oven.
Bake on the second rack from the bottom for 10 minutes, reduce the baking temperature to 190 °C, and bake for another 45 – 50 minutes.