
Pour lukewarm water in a bowl and sprinkle yeast on top; set aside for 5 min. In a small saucepan add buttermilk and shortening. Heat till shortening is melted. Do not over heat. Set aside till lukewarm. In a large bowl add white flour, 1 cup of whole wheat flour, brown sugar, baking soda and salt. Pour in yeast mixture and buttermilk mixture. Mix for a few minutes. Add remaining whole wheat flour, 1/2 cup at a time. You may want to put dough on a floured surface and knead in the whole wheat flour. Knead for about 8 min. until smooth and elastic. Place into a greased bowl turning dough to coat all sides. Cover with plastic wrap, till double. Punch down dough. Cut dough into two loaves and place in loaf pans. Cover and allow to double in size. Place in oven at 425 F for 35-40 min. Cool on wire rack.