1Preheat oven to 350 degrees F. Grease and flour a 9x5 inch loaf pan, knocking out excess flour.
In a large bowl, whisk together whole wheat flour, all-purpose flour, baking soda, and brown sugar. Mix in molasses and buttermilk until just combined. Stir in raisins. Pour batter into prepared pan.
Bake for one hour, or until done. Cool on a wire rack for 5 minutes, and then remove from pan. Cool completely before slicing.