MAKE THE SPONGE: In a large bowl, mix the whole wheat flour with the water and yeast until blended. Cover and let stand overnight at room temperature.
MAKE THE BREAD: In a medium saucepan, cover the rye berries with the water, add a large pinch of salt and bring to a boil. Cover and simmer over low heat until the rye berries are tender, about 45 minutes.
Drain and let cool to room temperature.
Add the rye berries to the sponge. Using a wooden spoon, stir in the rye flour, whole wheat flour, caraway seeds and 1 tablespoon plus 1 teaspoon of salt. When the dough becomes too stiff to mix, scrape it out onto a floured work surface. Using a dough scraper, lightly knead the dough, adding any leftover flour, until the dough forms a cohesive but sticky mass.
Transfer the dough to a clean bowl. Cover and let stand in a cool place until the dough increases in volume by two-thirds and holds an impression when lightly pressed, about 2 hours.
Scrape the dough out onto a lightly floured surface. Using floured hands, briefly knead the dough.
Cut it in half and shape each half into a 7-inch round.
Sprinkle a large peel or rimless baking sheet generously with cornmeal.
Transfer the loaves to the peel, leaving about 3 inches between them.
Let stand in a cool place until the dough is well risen and holds a slight impression when lightly pressed, about 1 hour.
Set a pizza stone or baking tiles in the bottom shelf of the oven. Preheat the oven to 350 for 30 minutes. Slide the loaves onto the preheated stone or bake on the baking sheet for 30 minutes. Reduce the oven temperature to 325 and continue baking for about 45 minutes, or until the loaves are nicely risen and browned; they should sound hollow when tapped on the bottom.
Transfer the loaves to a rack to cool for at least 4 hours before slicing.
Make Ahead: The bread can be refrigerated for up to 10 days.
