In a small bowl combine the yeast and ½ cup of water; stir and set aside for 5 mins.
In a large bowl add 2 cups of the Arrowhead Mills Unbleached Bread Flour and pour in the yeast. Mix and combine, slowly adding in 1 cup of water.
Sprinkle 1 cup of the flour over the top. Cover and set aside to rise for 6 to 8 hours (or overnight).
Add Arrowhead Mills Whole Wheat Flour, 1 cup of warm water and 1 cup of the Arrowhead Mills Unbleached Bread Flour to the bowl. Knead slightly.
Cover and set aside to rise for 6 to 8 hours or overnight.
Stir in the remaining 1 1/2 cups of water and flour.
Turn the dough onto the floured surface and knead it for 10 to 15 minutes.
Place the dough in an oil bowl. Cover and allow to rise for 2 to 3 hours.
Preheat the oven to 350 F.
Deflate the dough, pour into floured surface, and knead it briefly.
Form two oval loaves. Cover with a clean towel and allow to rise for 45 minutes.
Transfer the loaves to a baking sheet or baking stone.
Bake 10 minutes at 350 F then at 450 F 40 to 45 minutes.
Cool the bread on a rack before slicing.