Combine coffee and stout in a large bowl. Dissolve yeast in coffee mixture; let stand 5 minutes. Lightly spoon whole wheat flour into a dry measuring cup; level with a knife. Add whole wheat flour and wheat germ to yeast mixture; stir well to combine. Cover and let stand at room temperature 30 minutes to create a sponge (mixture will rise slightly and bubbles will form across the surface).
Lightly spoon the bread flour into dry measuring cups; level with a knife. Stir 1 1/4 cups bread flour and salt into sponge; stir until a soft dough forms. Turn the dough out onto a floured surface. Knead until smooth and elastic (about 8 minutes); add enough of remaining bread flour, 1 tablespoon at a time, to prevent dough from sticking to hands (dough will feel tacky).
Place dough in a large bowl coated with cooking spray, turning to coat top. Cover and let rise a second time in a warm place (85°), free from drafts, 1 hour or until doubled in size. (Gently press two fingers into dough. If indentation remains, dough has risen enough.) Punch dough down. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until doubled in size. Punch dough down; cover and let rest for 5 minutes. Shape dough into an 8-inch oval; place on a baking sheet sprinkled with 1 tablespoon cornmeal. Lightly coat the surface of dough with cooking spray. Cover and let rise in a warm place (85°), free from drafts, for 30 minutes or until doubled in size.
Preheat oven to 400°.
Cut a shallow 1/4-inch slash down center of loaf. Bake at 400° for 20 minutes or until loaf is browned on bottom and sounds hollow when tapped. Cool on wire rack.