Classes. There are eight classes for wheat: Durum wheat, Hard Red Spring wheat, Hard Red Winter wheat, Soft Red Winter wheat, Hard White wheat, Soft White wheat, Unclassed wheat, and Mixed wheat.

Durum wheat. All varieties of white (amber) durum wheat. This class is divided into the following three subclasses:

Hard Amber Durum wheat. Durum wheat with 75 percent or more of hard and vitreous kernels of amber color.

Amber Durum wheat. Durum wheat with 60 percent or more but less than 75 percent of hard and vitreous kernels of amber color.

Durum wheat. Durum wheat with less than 60 percent of hard vitreous kernels of amber color.

Hard Red Spring wheat. All varieties of Hard Red Spring wheat. This class shall be divided into the following three subclasses.

Dark Northern Spring wheat. Hard Red Spring wheat with 75 percent or more of dark, hard, and vitreous kernels.

Northern Spring wheat. Hard Red Spring wheat with 25 percent or more but less than 75 percent of dark, hard, and vitreous kernels.

Red Spring wheat. Hard Red Spring wheat with less than 25 percent of dark, hard, and vitreous kernels.

Hard Red Winter wheat. All varieties of Hard Red Winter wheat. There are no subclasses in this class.

Soft Red Winter wheat. All varieties of Soft Red Winter wheat. There are no subclasses in this class.

Hard White wheat. All hard endosperm white wheat varieties. There are no subclasses in this class.

Soft White wheat. All soft endosperm white wheat varieties. This class is divided into the following three subclasses:

Soft White wheat. Soft endosperm white wheat varieties which contain not more than 10 percent of white club wheat.

White Club wheat. Soft endosperm white club wheat varieties containing not more than 10 percent of other soft white wheats.

Western White wheat. Soft White wheat containing more than 10 percent of white club wheat and more than 10 percent of other soft white wheats.

Unclassed wheat. Any variety of wheat that is not classifiable under other criteria provided in the wheat standards. There are no subclasses in this class. This class includes any wheat which is other than red or white in color.

Mixed wheat. Any mixture of wheat that consists of less than 90 percent of one class and more than 10 percent of one other class, or a combination of classes that meet the definition of wheat.

Contrasting Classes. Contrasting classes are:

Durum wheat, Soft White wheat, and Unclassed wheat in the classes Hard Red Spring wheat and Hard Red Winter wheat.

Hard Red Spring wheat, Hard Red Winter wheat, Hard White wheat, Soft Red Winter wheat, Soft White wheat, and Unclassed wheat in the class Durum wheat.

Durum wheat and Unclassed wheat in the class Soft Red Winter wheat.

Durum wheat, Hard Red Spring wheat, Hard Red Winter wheat, Soft Red Winter wheat, and Unclassed wheat in the class Soft White wheat.

Durum wheat, Soft Red Winter wheat, and Unclassed wheat in the class Hard White wheat.

Damaged kernels. Kernels, pieces of wheat kernels, and other grains that are badly ground-damaged, badly weather-damaged, diseased, frost-damaged, germ-damaged, heat-damaged, insect-bored, mold-damaged, sprout-damaged, or otherwise materially damaged.

Defects. Damaged kernels, foreign material, and shrunken and broken kernels. The sum of these three factors may not exceed the limit for the factor defects for each numerical grade.

Dockage. All matter other than wheat that can be removed from the original sample by use of an approved device according to procedures prescribed in FGIS instructions. Also, underdeveloped, shriveled, and small pieces of wheat kernels removed in properly separating the material other than wheat and that cannot be recovered by properly rescreening or recleaning.

Foreign material. All matter other than wheat that remains in the sample after the removal of dockage and shrunken and broken kernels.

Heat-damaged kernels. Kernels, pieces of wheat kernels, and other grains that are materially discolored and damaged by heat which remain in the sample after the removal of dockage and shrunken and broken kernels.

Other grains. Barley, corn, cultivated buckwheat, einkorn, emmer, flaxseed, guar, hull-less barley, nongrain sorghum, oats, Polish wheat, popcorn, poulard wheat, rice, rye, safflower, sorghum, soybeans, spelt, sunflower seed, sweet corn, triticale, and wild oats.

Shrunken and broken kernels. All matter that passes through a 0.064 × 3/8 oblong-hole sieve after sieving according to procedures prescribed in the FGIS instructions.

Sieve—0.064 × 3/8 oblong-hole sieve. A metal sieve 0.032 inch thick with oblong perforations 0.064 inch by 0.375 (3/8) inch.