In a large mixing bowl thoroughly stir together 3 cups of whole wheat flour, salt, and undissolved yeast.
Into a small sauce pan turn the milk, water and butter over low heat, heat until liquids are very warm (120 to 130 degrees); butter does not need to melt.
Gradually stir into flour mixture and beat for 2 minutes on medium speed with electric mixer, scraping bowl occasionally. Add 1 cup of flour, beat at high speed for 2 minutes, scraping bowl occasionally. Stir in enough additional flour to make a stiff dough.
Turn out onto lightly floured smooth surface. Cover and let rest for 10 minutes. Knead dough until smooth and elastic (about 10 minutes). Place in a greased bowl, turning to grease top. Cover and let rise in a warm place until doubled (about 50 minutes).
Punch down dough and divide in half. Shape each half into a loaf and place in greased loaf pans. Cover and let rise again.
Bake in preheated 375 degree oven until loaves sound hollow when tapped (about 35 minutes). Turn out of pans onto wire rack and cool. Makes 2 loaves.