6 HANDLING WHEAT FROM FIELD TO MILL. 



will not produce good, sound flour. Furthermore, the indications 

 are that this excess moisture acquired by exposure in the field after 

 harvest continues to be a source of injury to the quality until the 

 wheat is dried either artificially or by natural means. 



"SWEAT" IN WHEAT. 



Millers, as well as operators of country and terminal elevators, 

 prefer wheat that has gone through the " sweat." The millers invari- 

 ably hold that sweating in the stack improves weathered grain and is 

 much to be desired. Comparatively little is known as to what the 

 process commonly referred to as " sweat of wheat" consists of. Very 

 little information concerning it can be gleaned from scientific litera- 

 ture. The following has been advanced as a possible explanation of the 

 change that takes place during the process. It is known that even 

 after wheat is cut the straw contains sufficient plant food to keep the 

 kernels in a growing condition for some time, and a chemical or 

 enzymic action within the plant by means of which this nutriment is 

 transferred to the grain and stored as starch may continue for a 

 considerable period. When wheat has been thrashed before going 

 through the sweat, it is probable that a rearrangement of the chemical 

 constituents of the kernels still takes place, and this will account for 

 the sweating of shock-thrashed grain in the bin. 



As chemical action is generally accompanied by the evolution of 

 heat, this may account for the heat usually generated during the 

 sweating process. The amount of heat generated appears to be in- 

 fluenced by the percentage of moisture present. Grain that has been 

 sufficiently ripened and is also very dry will give little evidence 

 through change in temperature that it is going through the sweating 

 process. On the other hand, wheat cut in the hard-dough stage, or 

 containing considerable moisture, goes into the sweat much more 

 quickly when stacked ; the straw becomes very tough and a great deal 

 of heat is evolved. Care should be exercised not to stack wheat of this 

 character before it is allowed to cure out in the shock for a few days ; 

 otherwise sufficient heat may be evolved, even in the stack, to injure 

 the grain, in which case " stack-burnt " wheat will result. 



Cutting the grain seems to act as a sort of check upon this biological 

 action, and it appears to remain in a dormant state until the assem- 

 bling of the grain in large bulk brings on a condition favorable to 

 activity. When the grain is stacked the straw permits to a limited 

 extent- the circulation of air through the stack, and this circulation 

 affords a means of conducting away considerable of the heat gen- 

 erated in stacked grain. 



HEAT-DAMAGED OR " BIN-BURNT " WHEAT. 



If wheat with a rather high moisture content is placed, before going 

 through the sweat, in a large bulk in a bin there is very little chance 



[Cir. C8] 



