EXERCISE 45 



Fig. 54. Sieves for determining dockage of 

 wheat 



THE COMMERCIAL GRADING OF WHEAT 



Statement. The most important factors in determining the commercial grades of wheat are class, 

 soundness, purity, moisture, content, dockage, and test weight. In grading wheat, official standards 

 have been prepared by the United States Department of Agriculture, under which wheat of any class 

 may be classified and graded. 1 



Object. To study the factors which affect the quality of wheat. 



Materials. Samples of wheat from at least ten different homes or that number of samples from a 

 local mill or elevator. 



Directions. Grade the samples obtained, and in the following blank form record the grades. In 

 grading wheat the region in which it is grown largely indicates the class to which it belongs. Most of 



the wheat grown east of the Mississippi River is classed as " Red 

 Winter " ; in eastern Kansas, Missouri, and in the south, it is 

 Red Winter; Kansas and Nebraska produce Hard Red Winter, 

 and Minnesota and the Dakotas, Hard Red Spring wheat; Durum 

 wheat is grown chiefly in western North and South Dakota and 

 Minnesota. Wheat of the Pacific coast states is Pacific Coast 

 White or Pacific Coast Red, according to color. 



If there is a flour mill or a grain elevator in the town, invite 

 the grain buyer to give one or two illustrated lessons to the 

 students, on grading wheat, oats, corn, etc., and then secure 

 the privilege of taking the class to the mill or elevator and using 

 the equipment and material in one or more laboratory exercises. 

 Perform these exercises at the mill or elevator and have the 

 students do the grading under the supervision of the teacher and the manager. 



In testing the sample of wheat first determine the dockage. All other determinations are based on 

 grain free from dockage. The materials removed from dockage include sand, dirt, weed seeds, stems, straw, 

 chaff, grains other than wheat, shriv- 

 eled or undeveloped wheat, wheat 

 grains, small pieces of wheat kernels, 

 and any other material which may 

 be readily removed from wheat by 

 means of the sieves shown in Fig. 54. 



Commercial wheats are divided 

 first into classes, of which there are 

 five : (1) Hard Red Spring, with three 

 subclasses : Dark Northern, Northern 

 Spring, and Red Spring ; (2) Durum, 

 divided into three subclasses : Amber 

 Durum, Durum, and Red Durum; 

 (3) Hard Red Winter, divided into three subclasses : Dark Hard Winter, Hard Winter, and Yellow Hard 

 Winter; (4) Soft Red Winter, divided into two subclasses: Red Winter and Red Walla; (5) Common 

 White, divided into two subclasses : Hard White and Soft White. 



The classes and subclasses are again divided into grades, of which there are six, designated as 

 1-, 2-, 3-, 4-, 5-, and 6-sample respectively. The specifications for the numerical grades are given in 

 the table on the opposite page. Sample grade comprises all wheats which do not fall into one of the 

 numbered grades of the class by reason of unsoundness, excessive moisture, garlicky odor, etc. Such 

 wheats are sold by sample instead of by grade. 



1 For complete regulations in reference to grading commercial grains write the Bureau of Markets, United States Department of 

 Agriculture, Washington, D. C. 



[90] 



Fig. 55. Showing the perforations of the wheat dockage sieves 



The one on the left is the scalper sieve, with circular perforations -fg inch in diameter; 

 next is the buckwheat sieve, with triangular perforations £ of an inch ; the next is the 

 fine-seed sieve, with perforations -fj of an inch in diameter; and the one on the right 

 is the chess sieve, with slot perforations ^X} inch. (Courtesy of the United States 

 Department of Agriculture) 



