In large bowl, sift together all the dry ingredients. Mix well. Cut in shortening until evenly mixed. Mixture will look like cornmeal. Put in a large airtight container. Make 13 cups of mix. Use within 10 - 12 weeks. Whole Wheat Mix: 4 1/4 c all purpose flour and 4 1/4 c. Whole wheat flour instead of 8 1/2 c ap flour. Increase baking powder to 5 tablespoons.