In a medium bowl, combine the water and molasses. Add the yeast and let stand until dissolved, about 10 minutes.
In a large bowl, sift 5 cups of the bread flour with the cornmeal, semolina and salt. Add the raisins and butter, then add the yeast mixture and blend well. Transfer the dough to a lightly floured surface and knead, adding up to 1 more cup of the bread flour to make a moist but not sticky dough. Continue kneading for a few minutes until smooth and elastic. Transfer the dough to a lightly buttered bowl, cover with plastic wrap and let rise until doubled in bulk, about 1 1/4 hours.
Punch the dough down and divide it in half. Form into 2 loose rectangular loaves and transfer to 2 buttered 8 1/2 -by-4 1/2 -inch loaf pans. Let rise until doubled in bulk, about 1 hour.
Preheat the oven to 375°. Bake the loaves for about 40 minutes, or until golden brown on top. Let cool in the pans for 5 minutes, then turn out onto a rack to cool completely.
The bread can tightly wrapped and frozen for up to 1 month.