In a medium saucepan, combine the cornmeal and 3½ cups water.
Bring to a boil over medium heat, stirring constantly, until the mixture thickens.
Let it cool.
In a large bowl, mix the barley flour, 4½ cups of whole wheat flour, and the cooled cornmeal mixture.
Knead on a lightly floured surface for about 10 minutes until the dough starts to come together.
Let it rest for 5 minutes, then knead for an additional 5 minutes, adding more whole wheat flour if needed.
Form the dough into a ball, dust with flour, and place it in a large bowl.
Cover it with foil and let it sit in a warm, draft-free spot, such as a kitchen cabinet, for 24 hours.
In a small cup, sprinkle the yeast over ¼ cup warm water.
Let it sit until the yeast becomes creamy, about 2 minutes.
Stir until the yeast dissolves.
Mix in the remaining ¼ cup whole wheat flour.
Add the yeast mixture and salt to the bowl with the dough and knead for about 5 minutes, adding more whole wheat flour if necessary.
Let it rest for 2 minutes, then knead for an additional 3 minutes.
Grease a large bowl with oil, place the dough in it, and turn it to coat.
Cover with a towel and let it rise in a warm place (such as an off oven) for 3 hours.
It may not double in size completely.
Punch down the dough and knead for another 5 minutes.
Shape it into a ball.
Sprinkle a cookie sheet with cornmeal or bread crumbs and place the dough on it.
Make two slits on the top.
Let it rise in a warm place for 1 more hour; it may not quite double in size.
Preheat the oven to 425°F with an oven rack in the upper-middle position.
Place a pan of water on the oven floor.
Bake the bread for 10 minutes.
Remove the water pan and bake for an additional 25 to 30 minutes or until the bread is well browned and sounds hollow when tapped on the bottom.