In a large bowl, dissolve yeast in 1/4 cup warm water. Add sugar; let stand for 5 minutes. Add the honey, oil, milk powder, salt, 3 cups whole wheat flour and remaining water; beat for 3 minutes. Stir in enough remaining whole wheat flour to form a soft dough.
Turn onto a surface dusted with all-purpose flour; knead until smooth and elastic, about 8-10 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 2 hours.
Punch dough down. Turn onto a lightly floured surface; divide into six portions. Shape each into a 15-in. rope. Braid three ropes; pinch ends to seal and tuck under. Repeat with remaining dough. Place in two greased 8x4-in. loaf pans. Cover and let rise until doubled, about 1 hour.
Bake at 350° for 30-35 minutes or until golden brown. Remove from pans to wire racks. Brush with melted butter. Cool.