Mix the flours, salt, and yeast together until mixed.
Put the molasses in the warm water, and stir so that it's incorporated.
Add the beer and the molasses water to the flour mixture and stir well.
Knead the dough for 5-10 minutes. It should be just a tiny bit sticky. By this I mean that the dough won't stuck all over your hands, but it will still feel a bit moist.
Let rise 1 hour in a bowl covered with plastic wrap.
Form into a ball, place on a lined baking sheet, and let rise for another hour.
Cut several slashes in the bread and dust with whole wheat flour. Bake 400°F. for 30 minutes. Cool on a wire rack.