Place white flour, cocoa, yeast, caraway seed and salt in a large bowl. Stir to mix. Place 2 cups water, honey and butter in a saucepan and heat until liquids are very warm. Add to dry ingredients and mix until moistened then beat very hard for 3 minutes. Stir in rye flour enough to make a soft dough.
Knead 8-10 minutes. Cover and let rest 20 minutes. Roll out and shape to fit 2 greased loaf pans. Brush tops lightly with oil, cover and let rise for 1 hour. Bake at 400 degrees for 25 minutes.