Sponge: Put the water into a large bowl and sprinkle over the yeast. Allow the yeast to rest for about 10 minutes. Stir the three flours together and add them to the yeast mixture, stirring with a wooden spoon.
Cover the bowl and let the sponge rest at room temperature for 6 to 8 hours, or put it in the refrigerator overnight.
Dough: If you've chilled the sponge, pull it out of the refrigerator about one hour before you're ready to continue with the recipe.
Dissolve the yeast in the water and pour it into the bowl with the sponge.
Combine the flours. Gradually add 2 cups of the flour to the sponge, mix well. Sprinkle the salt over the dough and mix in it.
Work in the remaining flour mixture and enough additional white flour to produce a dough that starts to clean the sides of the bowl. Knead for about 10 min (you can use the bread machine or mixer). The dough should be moist, satiny, even a bit sticky.
In a bowl, cover the dough with plastic wrap. Allow to rest at room temperature for 1 1/2 to 2 hours.
Turn the dough out to a floured surface. Pat it onto a flat round, fold the edges, press it down and turn the dough over. Repeat the process of folding four more times. Turn the loaf over and lay it smooth side up in a baking sheet sprinkled with corn meal. Slash the loaf in a pattern that appeals to you. Cover the dough and let it rest for 1 to 1/2 hours.
Oven: 400ºF. Pour some water into a spray bottle and set aside.
Bake the bread for 60 to 70 min (or until the crust is deeply brown), spraying the oven with water every 15 minutes.
Remove the loaf to a rack and allow it to cool before cutting. Store it cup side down on your counter (it's thick crust will be fine exposed to the air .