8 percent bran , the five outer coats of the wheat kernel are strong in woody fiber, mineral ingredients, and coloring matter. It is very indigestible in the human stomach and is excluded in the process of manufacture except where graham or whole wheat flour is desired. The proportions in which the several ingredients appear vary considerably in different wheat's. For example, Oregon white winter wheat contains about 9 percent gluten, Minnesota hard spring wheat about 14 percent, Oklahoma hard winter wheat about 15 percent. All wheat raised in low, damp districts contains more moisture, generally less gluten, and gluten of inferior quality than that raised in higher and dryer climates.
Soft wheat contains less gluten and more starch and water than hard wheat.
I Army Bibliography Deitrck, Capt. Manual for Army Bakers. This material is taken from pages 5-8.