In a large bowl mix the warm water with the yeast together, using a wooden spoon.
Add 2 1/2 cups of flour, 1 cup at a time to the water yeast mixture, mixing in one direction after ever cup is added until there are no lumps.
After the 2 1/2 cups of whole wheat flour has been added, cover the dough and let it rest for about 3 to 4 hours.
Sprinkle a tbsp of salt over the dough and stir in with the wooden spoon.
Add a tbsp of olive oil to the dough and mix.
Continue adding the remaining flour to the dough, one cup at a time. When you can no longer mix the flour in, turn the dough over onto a floured surface and continue kneading the flour in. Shape the dough into a ball.
Place the dough into an oiled bowl and rub some oil on the dough as well, cover the bowl and let the dough rise for another 2 to 3 hours.
Cut the dough into 16 equal pieces. Roll out each piece so that it is about 6 to 8 inches in diameter.
Grill the pita breads, until they are golden on each side.