In its broadest modern definition, a “mill” is simply a factory in which products are manufactured. The earliest mills, however, were associated with grain grinding, and evolved from hand methods employed for over 75,000 years. A small upper stone was rubbed back and forth across the grain, which was placed on a lower flat stone. This technique developed over many millennia until rotary motion was applied to the stones. They were turned by hand, in the case of querns or hand mills (Figure 1), by animals (Figure 2), then by water and later wind power. Water powered mills have been known for 2,000 years, and the basic power sources and transmission devices found in those earliest mills may still be seen today in surviving examples throughout the United States and the world.

Figure 1. Hand powered rotary quern

Figure 2. Horse powered corn sheller and grinding mill

Whatever the design for transmitting power to the millstones, the important element of history is the growth of mills as centers of commerce, activity, and community functions. Their immeasurable importance in removing the individual labor of reducing grain by hand methods has led historians to consider mills as one of the primary nuclei about which rural and later major communities evolved. Since the early mills were most commonly associated with a source of water power, their functions were not long limited to simply the milling of grains. They became sawmills, textile mills, and factories for the production of a wide range of goods, including paper, iron, gunpowder, paint, snuff, tanbark, cider, molasses, crushed ore, oil, and mustard.

Figure 3. Monolithic native granite millstone on left; segmented French buhrstone on right. Both stones have trammels in place for checking shaft perpendicularity to bedstone.

Mills of any magnitude had to be located on rivers and streams to provide adequate power until the introduction of steam engines in the late eighteenth century. By the early nineteenth century, these prime movers had become well established, and water power began a steady decline in importance. With the introduction of internal combustion engines and electrical power beginning primarily in the 1880’s and 1890’s, even steam engine use eventually diminished.

Since most surviving mills and mill sites are associated with grain milling, it is important to understand some major advances in this industry between the late eighteenth century and twentieth century. Prior to 1785, virtually all grain mills employed stones powered by water for the reduction of grain, and many also used bolting (sifting) devices for separating the finer flour or meal from the bran or coarser ground product. Most processes other than the actual grinding, from unloading the grain, through moving the milled products from stones to bolters, to bagging, were performed by operatives who were required to lift and carry bulky material with aid of few if any transporting devices (Figure 4). This required several employees in addition to the miller and slowed the entire process dramatically. In fact, most millwrights to that time had not perceived that the power train which drove the millstones could also be harnessed to turn bolters, cleaners, and other machinery within the mill. Those peripheral but integral steps were performed manually.

Figure 4. Typical milling operation prior to automation.

The most significant step in milling since the application of water power was the automation and mechanization of the entire milling process. This was conceived and accomplished by Oliver Evans, a great American inventive genius and practical engineer whose name is little known today. Although Evans did not invent many of the devices he utilized, he applied them for the first time to grain milling. These included the elevator with small cups on a continuous belt to carry grain upward and the screw conveyor that moved products horizontally. His mills, when kept maintained in good running order, could be operated successfully by only one individual. Evans’ most famous written work, now considered a classic by technology historians, is The Young Mill-wright and Miller’s Guide, first published in 1795 and issued through 13 editions, the last in 1850, 31 years after Evans’ death.

During the period when Evans’ improvements began to find favor among millers and millwrights, a process of producing flour known as the American or flat-grind system was in use. In this system, wheat passed between the millstones only once for grinding. The stones were set very close together and were run fast with a heavy feed. The meal exited the stones in a damp and hot state, with the bran broken into fine bits, which would clog the bolting cloths if not cooled first. In the pre-Evans mills, this flour was spread across the mill floor, cooled, and then transported to the bolting hoppers for sifting out the bran and “middlings,” or coarse particles of flour. Young boys were usually employed to move the flour from stones to floor to bolter. Evans’ invention of the “hopper-boy,” a mechanical device for collecting, cooling, and conveying the flour automatically to the bolters, was at the time a great labor-saving innovation.

However, after the mid-nineteenth century, this old process had been for the most part abandoned in favor of what was called the New Process of high grinding. The main purpose was to produce purer flour that could command a higher market price. The basic elements of the New Process were the use of a primary set of millstones set wider apart to accomplish the first reduction, a middlings purifier (perfected in the 1870’s but introduced several years earlier) to separate via sifting and fanning the bran from the middlings, and a second set of millstones to regrind the purified middlings and obtain more flour. This method of high grinding thereby reduced the overheating and destruction of nutrient value in the flour. On the other hand, the separation of the bran and whole grain to produce fine white flour demanded by the public somewhat offset the advantages of reduced heat, nutritionally speaking. The flour from the first grind of the wheat was called the baker’s or clear flour, and the second yield was called “patent” flour. Often these were blended after the second grinding and sold as “straight” flour.

The next major development in grain milling was the introduction of the Hungarian or roller process for flour. Although steel rollers had been employed on a limited basis to crush wheat as early as the 1830’s in Europe, they had not been entirely successful until iron production techniques were improved. By the 1860’s and 1870’s, roller milling developed rapidly in Budapest, Hungary. The process interested Charles Pillsbury and other American mill owners to the extent that they traveled to Hungary to study the methods. Not long after, roller mills were being manufactured in America with a myriad of improved and newly patented designs and materials. They found favor in the larger milling establishments, which had the capital necessary to invest in the dozens of machines needed for the entire flour production process. Millstones for flour grinding gradually lost out in part because they were so laborious to sharpen, or “dress.” During this period, particularly the 1880’s and 1890’s, large three and four-story structures were erected to house the roller equipment. The earlier large merchant mills disposed of their stones and adapted their structures to the new roller process, but many in rural areas kept one set of millstones for custom and corn grinding.

Figure 5. Vertical stone buhr mill of the early twentieth century.

ran faster, and could be powered by a small engine or motor. They appealed to the country stores particularly, and the store owners would buy them to perform custom grinding for the local community. This cut into the markets of the old water mills, and began their more precipitous decline. In addition, with larger power units available in the form of massive steam engines and electric motors, better transportation methods, increased demand, and improved yields and farming techniques, mills became quite large. Because of their size and market command, they could buy cheaper grain in larger quantities than their small competitors, and eventually took over. By the 1950’s small water powered milling operations were all but extinct, and the country stores on which they depended were closing as large grocery chains captured the public’s fascination and business.

Today, a low-key and peculiar trend is developing. A small but growing percentage of the public, chefs, and bakers are becoming aware of the nutritional advantages of whole grain, stone ground mill products. This development has allowed a very few of the traditional water mills to establish niche markets, catering to mail-order customers, specialty bakeries, and health food stores.

Excerpted from Historic Context Evaluation for Mills in Tennessee, by John N. Lovett, Jr., Ph.D., May 2002. John assists with mill restorations throughout the United States, and he and his wife Janie have owned and operated Falls Mill near Belvidere, Tennessee, since 1984.