In a large bowl, combine the yeast and warm water; let stand until softened, about 5 minutes. Add rye and whole-wheat flours, molasses, cocoa, caraway seeds, and salt. With an electric mixer, or heavy spoon, beat dough until it is mixed very well.
If using a dough hook, mix in 1 cup of flour. Knead until the dough is elastic and pulls cleanly from the bowl, about 5 minutes.(If needed,add more flour, ! Tblsp. at a time.).
If mixing by hand, stir in 1 cup flour with a heavy spoon. Scape the dough onto a floured board. Knead, adding as little flour as possible, until the dough is smooth and elastic, about 5 minutes.Place the dough on a plastic counter and cover with a large stain-less steel bowl. Allow the dough to rise until double in bulk, about 1 hour.
Sprinkle the cornmeal in the center of a baking sheet; set aside. Punch down the dough. On a lightly floured board, knead the dough to shape into a ball. Place the dough on the cornmeal and press to form a 6-inch round. Let the dough rise in a warm place until almost double, about 30 minutes.
Sprinle a bit of additional flour on top of the loaf. Bake in a 350* oven until the loaf is a rich, dark brown, about 30 minutes, or until the bottom sounds hollow when tapped. Transfer to a cooling rack. Serve warm or at room temperature.
Hint: For a Crunchy Bread Crust use a water sprayer while baking. Your plant sprayer will do fine, as long as it is clean. Simply spray a bit of water into the oven now and then as the bread bakes. Works great!