To the yeast mixture, add the oil, salt, and 2 cups flour. Stir in the remaining flour, 1/2 cup at a time, until the dough has pulled away from the sides of the bowl. Turn out onto a lightly floured surface, and knead until smooth and elastic, about 8 minutes. Lightly oil a large bowl, place the dough in the bowl, and turn to coat. Cover with a damp cloth, and let rise in a warm place until double in volume, about an hour.