MOISTURE IlSr WHEAT AND MILL PRODUCTS. 7 



DISTRIBUTION OF MOISTURE IN THE TEMPERED WHEAT KERNEL. 



An examination of the data of part 2 of Table II shows that as the 

 process of miUing progressed from the breaks to the sizings and 

 middhngs reductions, and then to the taihngs and low grade reduc- 

 tions, the moisture content of the streams of stock on the various 

 roUs became less and less. Figure 1, which gives a graphic representa- 

 tion of the relative amounts of moisture present at the successive 

 steps in the milling process indicated in this part of the table, 

 illustrates this fact more clearly. The curves shown in this figure 

 represent, for each mill, the differences in the moisture content of 

 the various streams of roll stock before grinding. 



An interesting point to note in this connection is that the moisture 

 content of the second, third, and fourth break streams in the instance 

 of mills Nos. 2 and 3 was higher than that of the wheat on the first 

 break roU. In the part of the milling process known as the break 

 reductions, there is a gradual reduction of the wheat kernel resulting 

 in a more or less complete separation of the middlings or endosperm 

 particles from the bran. This fact, considered in connection with the 

 point mentioned above, leads to the conclusion that for the cases 

 examined, very little of the v\^ater added in tempering penetrated 

 farther than the outer coatings of the kernel. 



It is a well-known fact that fifth and sixth break streams are 

 composed of a greater percentage of bran than the preceding breaks, 

 and in accordance with the conclusion just stated, should contain a 

 correspondingly higher percentage of moisture. The results shown 

 here, however, are of a contradictory nature. The probable explana- 

 tion of this apparent inconsistency is that the loss of moisture through 

 evaporation at the time of grinding and bolting exceeded any increase 

 in the moisture content of such streams caused by the elimination of 

 drier particles. 



It is observed also that the roll streams containing the lesser 

 amounts of moisture were those known as the low grades, which 

 streams occur at the extreme end of the milling process. This low- 

 grade stock is composed of very small bran and germ particles 

 together with such endosperm particles as are unavoidably removed 

 with them when the former are separated from the various streams of 

 reduced middlings. The probable reason for their lesser moisture 

 content is the fact that the parts of the kernel composing these 

 streams are subjected to the grinding action of the roUs a greater 

 number of times and, consequently, are exposed to the drying effect 

 of the atmosphere much more than those composing the other streams. 



An interesting observation in connection with the data given in 

 parts 1 and 2 of Table II is that, in spite of the relatively great differ- 

 ence among the mills in the moisture content of the wheat at the 



