In a bowl, combine 5 cups flour, sugar, dry milk powder, yeast and salt. In a saucepan, heat water and butter to 120°-130° (butter does not need to melt). Add to flour mixture. Beat on low speed until moistened; beat on medium for 3 minutes. Add enough remaining flour to form a soft dough. Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour. Punch dough down. Divide into thirds; shape into loaves. Place in a greased 8x4-in. loaf pans. Cover and let rise until doubled, about 45 minutes. Bake at 350° for 25-30 minutes or until golden brown. Remove from pans to wire racks.