This Rye Bread, Made with 66 Percent Rye Flour, has full flavor and good keeping quality. The medium rye makes a loaf somewhat lighter than if whole rye were used. The degree of sour flavor can be adjusted by lowering the percentage of rye flour used in the sourdough phase. In that case, be sure the final dough-ingredient weights are properly adjusted as well. As the percentage of rye flour increases in a dough, rolls become more difficult to make, because the dense texture of the dough makes rolls with too high a proportion of crust. Sixty-six percent rye flour may be at about the upper limit for roll production.