1. Preheat oven to 350°.
2. Weigh or lightly spoon flours into dry measuring cups; level with a knife. Combine flours, cornmeal, raisins, baking soda, and salt in a large bowl; stir with a whisk. Combine buttermilk, molasses, butter, and rind. Add to dry ingredients; stir just until moistened. Divide batter evenly between 2 (8-inch) loaf pans coated with cooking spray. Tightly cover each pan with foil. Place pans in a 13 x 9–inch baking pan. Add boiling water to a depth of 1 inch. Cover larger pan with foil.
3. Bake at 350° for 1 hour and 10 minutes or until a knife inserted in center comes out clean. (Top of bread will feel slightly sticky.) Remove pans from water. Cool 10 minutes on a wire rack. Remove from pans; cool completely.