Directions

1. In a large bowl, stir together the warm water and sugar. Sprinkle the yeast over the top and let stand until foamy, about 5 minutes.
2. Stir in the salt, whole wheat flour and rye flour. Mix in the bread flour 1 cup at a time until the dough is not sticky. Knead on a floured surface until smooth and elastic, about 10 minutes. Place in an oiled bowl, turning to coat. Set aside to rise until doubled in size, about 1 hour.
3. Punch down the dough and divide into 4 or 5 portions. Form each one into a ball, and let rise again until doubled, about 20 minutes.
4. Place each ball onto a baking sheet and flatten out into an oval 1/2 to 3/4 inch thick. Poke holes all over using the tines of a fork. Let rise again until doubled, 20 to 30 minutes. Preheat the oven to 350 degrees F (175 degrees C).
5. Bake for 20 minutes in the preheated oven, or until browned on the top and bottom. Brush the tops with butter while still warm.