4 BULLETIN 215, U. S. DEPARTMENT OF AGRICULTURE. 



supply the local demand. While the southern corn is used as far as 

 it goes, and is usually preferred, the larger part of the meal is either 

 ground by southern mills from western corn or is milled in the 

 North, usually in or near the region where the corn is grown. 



THE STONE PROCESS. 



With few exceptions the southern mills grind the corn by stones. 

 The chief difference between the process of the small country mill 

 with a single "run of stone," which grinds the grist that the farmer 

 brings in on his back, and that of the large mill, with several to 40 

 or 50 "run of stone," is in the perfection of the grain-cleaning and 

 the bolting systems. In many of the mills native stones, notably 

 the so-called Esopus stones from New York quarries, are preferred to 

 French buhrs for the reason that they produce a soft, smooth meal, 

 which is highly esteemed by southern cooks. 



The term "water meal" has been applied indiscriminately to old- 

 fashioned, stone-ground meal regardless of the fact that at the pres- 

 ent time steam or even electricity is often the motive power. Natu- 

 rally the nature of the milling machinery and not the power deter- 

 mines the character of the meal. Stone-ground meal is either milled 

 from corn without bolting, and consequently does not differ in com- 

 position from the whole grain, except for the removal of a small 

 amount of chaff by a simple fan device, or is bolted to remove the 

 coarse bran and germ. It is stated that when unbolted meal is 

 used the cook is accustomed to put it through a sifter, thus removing 

 the greater part of the coarse, branny tissues, so that the final result 

 attained is the same as if bolted meal had been used. Stone-ground 

 meal, owing to the incomplete removal of the fatty matter of the 

 germ, is characterized by its rich oily flavor, the taste for which when 

 once acquired is not satisfied by degerminated meal in which the fat 

 content is reduced to the minimum. 



In the small stone mills no attempt is made to dry either the corn 

 or the meal, although it is well known that the corn must be moder- 

 ately dry in order to prevent gumming in the mill and to insure 

 keeping for a reasonable length of time. The friction of grinding, 

 especially when the stones are set for producing a very fine, soft meal, 

 develops considerable heat, which serves to drive off much of the 

 moisture. In certain of the large mills drying apparatus is used to 

 some extent for removing the excess of moisture from either the 

 corn or the meal. In many of the mills, however, dependence is 

 placed on the heat developed during grinding as well as on the expo- 

 sure of the hot meal to the air in open conveyors. 



THE ROLLER PROCESS. 



In northern mills rolls have largely replaced stones, the process 

 being one of gradual reduction similar to that employed in wheat 

 milling. Preliminary to grinding, the corn is put through the 



