In a large bowl, whisk together the flours, salt, and baking soda, and then set aside.
In a separate bowl, whisk together the buttermilk, eggs, and molasses. Add that into the dry ingredients, and stir everything together until a rough dough forms.
Then add in the stout a little bit at a time until a wet dough forms. You want the dough to be wet but not liquidy like pancake batter. You may add the full amount of stout or only part of it. It just depends on how much liquid your flour absorbs.
Pour the dough into a loaf pan that has been greased and floured. Using a spatula, smooth the dough in the pan, so no large air pockets form while baking. You can leave the bread as is or sprinkle rolled oats on top for an attractive added touch. Gently press the oats into the top of the bread so that they adhere to the loaf during baking.
Bake the bread in a 265℉ / 130℃ pre-heated oven for 1 hour and 30 minutes to 1 hour and 45 minutes. The internal temperature of your bread should be at least 185℉ / 85℃ before removing it from the oven.
Let the loaf cool in the pan for 10 minutes, and then pop it out of the pan and let it cool on a rack completely before slicing into it.
