UNITED STATES DEPARTMENT OF AGRICULTURE 
s^S-'^ru 
BULLETIN No. 328 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
December 30, 1915 
MILLING AND BAKING TESTS OF WHEAT CON- 
TAINING ADMIXTURES OF RYE, CORN COCKLE, 
KINGHEAD, AND VETCH. 
By R. C. Miller, Assistant in Charge of Dockage Investigations, Office of Grain 
Standardization. 
CONTENTS. 
Page. 
Introduction 1 
Frequency ol occurrence of impurities in 
wheat 2 
Comparison of the specific gravity of wheat 
and of its impurities 2 
Methods of preparation and milling 3 
Descriptions of the different impurities 5 
Comparative milling yields of wheat and of 
its impurities 10 
Milling and baking tests of wheat contain- 
ing impurities 10 
Page. 
Tests with flour blends 17 
Tests with wheat containing kinghead seed. . 18 
Tests with wheat containing wild- vetch seed, 
as grown 19 
Analyses of wheat, of the impurities, and of 
flour containing admixtures 20 
Special cleaning devices 22 
Mechanical an alyses of corn-cockle screenings . 22 
Summary 23 
INTRODUCTION. 
Wheat as grown and as marketed frequently contains various kinds 
of so-called inseparable impurities, such as rye (Secale cereale), corn 
cockle (Agrostemma githago), kinghead, or great ragweed (Ambrosia 
trifida), and wild vetch (Vicia angustifolia) . These impurities are 
considered inseparable, inasmuch as they are not readily removed 
from wheat by the grain-cleaning machinery in general use in grain 
elevators and flour mills, because of their similarity in size, shape,, 
and specific gravity to the wheat in which they occur. 
Millers claim that the presence of these impurities in wheat in 
appreciable amounts injures the milling and baking qualities of the 
flour. The result is that wheat which contains a noticeable amount 
of these ingredients when marketed is generally penalized by being 
— % — 
Note.— The data presented in this bulletin are applicable to the, wheat-producing sections of the 
"United States and are of interest to farmers, grain dealers, flour millers, and bakers. 
10373°— Bull. 328—15 1 
