Catharine Fiedler, age 12, of Portland, Ore., for her question:
WHEN WAS FLOUR FIRST MADE?
Grain was most likely one of man's earliest foods. The pounding of grain into flour may well have been the world's first industry. Prehistoric man must have discovered that wheat could be chewed more easily if crushed first. He was quick to learn that grain placed on a large flat stone could be pounded into meal with a smaller stone.
In time, historians tell us, the lower stone was worn away by the pounding of the smaller stone. A hollow in the surface of the stone suggested a crushing or grinding method of milling flower.
It was found that a movable round stone could be rocked back and forth on the grain placed in the hollow stone. This crude method of flour making served for a long time. Even today some American Indians pound their maize between two stones.
Grinding grain by a rotating motion was the next step in the milling process. About the year 200 B.C. the first complete milling machine, called the quern, was invented.
The quern brought about an important change in the grinding of grain into flour. In the center of the upper stone was a hole through which the grain could be poured without stopping the grinding. The grinding stone was turned by a handle which was fastened to its side.
The first quern was small and could be operated by a single person. Each family had its own quern. The milling was done by women and slaves of the household.
When the querns became larger, convicts or animals furnished the power to turn them.
The invention of the water mill, about the year 100 B.C., was a step forward in the milling process. This method used water power instead of labor of men and beasts. The water mill was based on the same principle as the quern, but was revolved by power gained from the current of a stream.
Wind as a power for turning millstones was first used by the Dutch in the Middle Ages.
The final step in the development of the flour mill was the substitution of power engines for the water mills and the windmills.
The modern process of milling is complex, requiring elaborate machinery. The operation can be divided into five main processes: cleaning, grinding, bolting, purifying and bleaching.
During cleaning, the husks are removed and impurities are separated and removed. Individual particles are sifted to suitable size. The largest flour particle which is permitted must pass through the meshes of woven silk having about 10,000 openings to each square inch.
In the manufacture of white flour it is necessary to separate the bran and germ from the inner cells. These cells are reduced to the soft, white product used mostly for bread making.
In milling brown flour either all or part of the bran is kept. In "whole wheat" flour a portion of the bran has been removed.
The hull has no food value and is always discarded. When the entire wheat kernel is ground into meal, it is called graham flour.