In a large bowl, dissolve yeast in water. Add the flours, and salt. Stir until well blended. The dough should be shaggy and sticky. Let rise overnight, at least 12-18 hours, for best results.
Flour a work surface. Fold dough over itself once or twice. Place the dough, seam side down, on a floured kitchen towel. Cover with another floured kitchen towel.Let the dough rise at room temperature for 1-2 hours.
Preheat the oven 20 minutes before the dough is ready to 475 degrees. Put the dutch oven into the oven. When dough is ready, take out the dutch oven, and then using the kitchen towels, flip the dough into the pot, seam side up. Shake the pot if the dough loses it's shape.
Cover and bake for 30 minutes. Uncover and bake for 15-20 minutes, or until the dough is turned golden brown. Cool on a wire rack, and enjoy!