EXPERIMENTAL MILLING AND BAKING. d 
Some of the factors which serve as the basis for the grades were 
chosen because of the existence of a definite relationship to milling 
quality, some for their relationship to baking quality, others for their 
relationship to keeping quality in storage and transportation, and 
still others for their relationship to intrinsic worth. In regard to 
factors affecting milling and baking quality, the test weight per 
bushel of a wheat of any given class or subclass is a good index to its 
flour-yielding capacity; the presence of damaged kernels affects the 
quality of the flour; and the presence of foreign material may affect 
either or both flour yield and baking quality. The extent to which 
milling and baking qualities are affected by damaged kernels or foreign 
material depends upon the amount present and the type. In the 
case of damaged wheat the quality is also influenced by the degree 
or extent to which the individual kernels are damaged. 
The basis for the present wheat standards is explained in the 
preceding paragraphs to show the importance of milling and baking 
experiments, but it should be remembered that milling and baking 
tests are necessary not only that proper grain standards may be 
established for commercial inspection purposes but also that the 
most suitable kinds of grain may be bred, introduced, and grown. 
This bulletin contains descriptions of: (1) The method of handling 
and analyzing the samples received for milling and baking tests, 
(2) the experimental mill and its operation, (3) the baking labora- 
tory and the method used in baking, and (4) the equipment and 
methods of analysis used in determining the chemical constituents of 
grain and mill products. 
METHOD OF HANDLING SAMPLES. 
Each sample of grain received for a milling and baking test is 
assigned a laboratory number which, with certain information 
furnished with the sample, is recorded in a book kept for that purpose. 
The character of information recorded is indicated on the record 
sheet shown in Figure 1. This information is later transferred to a 
laboratory card (see figs. 2 and 3) , which follows the sample through 
the various tests applied and forms the final record of the results of 
all these tests. The size of the samples obtained usually ranges 
from 4 to 8 pounds. 
After the sample has been recorded, it is placed in a tin can, if of 
the usual size, and in a metal-lined bin if larger. The tin cans are of 
the baking-powder type, shown in Figure 4, and are of two sizes 
capable of holding approximately 6 to 8 pounds of grain. The bins 
are lined with galvanized iron and have a capacity of about 4 bushels. 
The use of tin cans and metal-lined bins prevents mice and rats, and 
to some extent insects, from destroying the samples. 
In the storeroom, the tin containers are filed or arranged on shelves 
in numerical order. At frequent intervals the storeroom is fumigated 
with carbon disulphid to destroy ants, weevils, moths, and other 
insects which may be present. 
MECHANICAL ANALYSIS OF SAMPLES. 
As the wheat samples are needed for milling purposes they are 
analyzed for all the factors indicated on the face side of the laboratory 
card (fig. 2), and their grade determined. In making this analysis, 
