Mix bread flour, whole wheat flour, and salt in a bowl.
Dissolve the yeast in lukewarm water.
Add the yeast water and additional water to the flour mixture and knead into a dough.
Let the dough rise for the first fermentation.
Shape the dough and let it ferment again.
Bake in a preheated oven at 180°C for 35 minutes.
Cool on a wire rack.