2 cups rolled oats
2 cups bran flakes
1/4 cup molasses
4 teaspoons salt
2/3 cup vegetable oil
3-1/2 cups boiling water
2 envelopes active dry yeast
1/2 cup lukewarm water (105°F)
1 teaspoon sugar
3 cups mashed potatoes
4 cups whole wheat flour
1-1/2 cups rye flour
5 to 6 cups bread flour

Grease a large bowl; set aside. In a large bowl, combine oats, bran flakes, molasses, salt, oil, and boiling water; stir well to blend. Cool to lukewarm (105°F).

In a small bowl, dissolve yeast in water with sugar; let stand until foamy, about 5 minutes. Add dissolved yeast, potatoes, and whole wheat flour to oat mixture; beat until smooth. Add rye flour; beat until smooth. Stir in enough bread flour to make a soft dough.

Turn out onto a well floured board; knead 8 to 10 minutes until smooth and elastic. Place in prepared bowl; grease top lightly. Cover; let rise in a warm, draft-free place until doubled, about 1-1/2 hours.

Spray 3 9x5-inch loaf pans with non-stick vegetable spray.  Punch dough down; knead briefly. Divide dough into 3 equal pieces; shape into loaves. Place in prepared loaf pans; grease tops lightly. Cover; let rise until doubled, about 1 hour.

Preheat oven to 375°F. Bake 45 to 50 minutes or until loaves sound hollow when lightly tapped. Remove from pans; cool completely on a wire rack.