2 BULLETIN 1187, U. S. DEPARTMENT OF AGRICULTURE. 
poses in so far as this is possible in practical application. The value 
of wheat is almost entirely dependent upon its milling and baking 
quality, which can be accurately determined only through actual 
milling and baking tests. Such tests, however, are impracticable 
for use in grading, because of the time, technique, and equipment 
required, but are necessary for determining the essential factors in 
fixing equitable standards. Equitable standards should truly reflect 
or indicate, first, relative commercial values including differences 
in quality due to climate or geographical location of production, 
and second, the relationship existing between the various physical 
and chemical properties of wheat and its milling and baking quality. 
Under the present standards wheat is, first, divided into general types 
or classes; second, these classes are subdivided into subclasses on 
the basis of differences in baking strength; and third, the subclasses 
are subdivided into grades based on cleanliness, quality, and condition. 
There are five classes of wheat which take into account botanical 
differences, including color, texture, habit, and difference in use. 
For instance, the hard red spring class is composed of the common 
hard red wheats of spring habit. These are especially well adapted to 
the manufacture of bread flours. The durum class is composed of 
all durum wheats. These are used principally for semolina for the 
manufacture of macaroni and other alimentary pastes. The hard 
red winter wheat class is composed of the hard red varieties of common 
wheats of winter habit and is used primarily for the production of 
bread flours. The soft red winter class is composed of the soft red 
varieties of common wheats of winter habit and the red club wheats. 
This class is best adapted to the production of flour for pastry, hot 
biscuits, and crackers. Some of the wheats of this class also produce 
a very satisfactory bread flour. The white class is composed of the 
common white varieties and the white club wheats. With the 
exception of the white club varieties, which produce a granular, 
creamy flour, this class is adapted to the same uses as the soft red 
winter class, and, in addition, on account of its color, is used exten- 
sively for the manuf activre of those breakfast foods in which the whole 
kernel is utilized. 
Each class of wheat is divided into subclasses which are intended to 
reflect differences in quality within the class. For example, hard red 
spring wheat is divided into three subclasses — dark northern spring; 
northern spring, and red spring. The determining factors are kernel 
texture, variety, and geographic location of production. In the hard 
red spring, durum, and white wheat classes, the subclasses are based 
partly on kernel texture and partly on variety. In the hard red 
winter class, kernel texture alone determines the subclass, while in 
the soft red winter wheat class, variety and geographical location of 
production are the subclass determinants. 
The subdivision of the various subclasses into numerical grades is 
made in accordance with certain definite limitations or requirements 
as to test weight per bushel, moisture content, total percentage of 
damaged kernels, heat-damaged kernels, total percentage of foreign 
material other than dockage, matter other than cereal grains^ total 
amount of wheats of other classes, wheats of special classes , foreign 
odors, temperature, presence of live insects injurious to stored grain, 
distinctly low quality, small inseparable stones and cinders, ..nd 
special varieties. 
