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The Automation of Flour Milling in America

The Young Mill-Wright and Miller's Guide, by Oliver Evans, 1795
A Cross Section of a Typical Oliver Evans Mill
The Same Typical Oliver Evans Mill Shown in Side Cross Section
Schematic Layout of a Typical Oliver Evans Mill
The Hopper-boy of Oliver Evans
The Automation of Flour Milling in America, Part 2
Reference Works on Oliver Evans
Illustrations of Oliver Evans, Steam Engine & Dredge

The Automation of Flour Milling in America
Part 1

Theodore R. Hazen

Before the Industrial Revolution, mills traditionally derived their power from wind, tidal and water (stream) power. The wind, sea and streams supplied the energy that turned wind wheels and water wheels. Inside the mill, the rotating main shaft turned the wooden gears which provided power to operate the grinding machinery of the millstones.

Until the beginning of the 1700's, the sifting of ground flour was often done by hand. Either the baker or a separate milling facility, the boulting mill, would do this task. A change came with the addition of boulting (sifting) machines to mill operations. The gearing remained simple and not much extra power was available for these new machines. Water wheels were crudely designed, inefficient structures. To operate just a single pair of millstones might require 3,000 to 5,000 gallons of water per minute, depending upon the diameter of the millstones.

Up until the late 1700's, most mills contained only the millstones and possibly a sack hoist to lift the sacks of grain from level to level within the mill. Eight to ten men and boys had to do all other tasks. With the process improvements and mechanical inventions of American Oliver Evans, milling beccame automated. One or two men could produce three times the amount of grain and at a better quality and consistency.

Traditionally, the millwrights who built the mills learned from their fathers or through the apprentice system. Written technical information was unknown and one simply built what he had learned, adapting his knowledge to suit each mill site. If a millwright learned his craft in Europe and was taught only to build undershot water wheels, that is what he built when he came to America. So it was not uncommon to find an undershot water wheel being powered by a 40 foot fall of water. Not until much later did millwrights have available tables and studies telling that an overshot water wheel would make more efficent use of the fall. Little was known about the comparative efficency of the various types of water wheels until 1829 when the Franklin Institure made their studies of various water wheel types.

Whether the milling operation was small or large, the process would be the same. Most small mills had only one pair of millstones. Perhaps in rare cases a mill might have two pairs of millstones. Because water wheels were simple and not very efficient, to operate an additional pair of millstones, another water wheel was usually required. The small mills with one pair of millstones often did custom grinding, where the miller ground each batch of grain individually for each person who brought it to the mill. In custom grinding the method of payment was for the miller to collect a toll or portion of the grain for his services.

Since milling was a craft that was learned through the apprenticeship method, the millers and the millwrights safe guarded their knowledge and secrets. Often when a farmer brought his grain to the mill, he would never see the mill operating. The miller, upon seeing someone coming, would turn off the mill and ask the person to leave their grain and come back later to pick up the ground flour. A dishonest miller could easily steal a portion of the ground grain, sometimes replacing the loss with sawdust. So hundreds of years ago people got away from brown flour. Because it was more expensive to adulterate white flour than to adulterate brown flour, customers requested white flour to make it less likely that the miller would cheat them.

Back in Europe millers had been looked upon with great suspicion and distrust. Millers were considered so dishonest that harsh laws were passed to regulate them. They were forbidden to own mills. The miller's tolls were set by law. Millers could not form guilds or determine what they would grind, nor could they sell their products in open air markets like their compeers the bakers. The millers were forced to rent their mills from the Lord of the land. If the Lord thought the peasants were not paying him his just due, he would make the miller steal from the poor peasants.

In American things were different, free of the restraints imposed by European feudalism. The farmers were free to go to whatever mill they wished. The word of a dishonest miller would spread and soon he would lose all of his business. Commercial milling operations were still few and they were simply larger sized carbon copies of smaller mills. Early mills relied upon the miller and his helpers to hoist sacks of grain and move ground flour within the mill. The milling process was very labor intensive. Yhe majority of mills did not have a means of cleaning grain. The farmer brought his grain to the mill and the mixture of grain,dirt, seeds, chaff and filth were all together. The miller simply sifted out the flour after it was ground, sifting the brown from the white, and hopefully with the brown parts of the wheat also went the brown dirt.

The big change in the milling industry came in the 1780's with the ingenious ideas of Oliver Evans (1755-1819)from Delaware. Oliver Evans' two brothers bought some land from their father on the Red Clay Creek in New Castle County, Delaware, and wanted to build a mill. Since Oliver was mechanically inclined, they asked him to design and install the milling machinery. Oliver Evans was not trained as a miller or millwright. He had been apprenticed to a wheelwright at the age of 14. Yet Oliver Evans when he was 22 developed machines for the manufacture of wool carding teeth and hand carders.

Oliver Evans
September 13,1755 - April 15, 1819

He had recently moved to Tuckahoe, near Nine Bridge on Maryland's Eastern Shore. There he and his younger brother Joseph had opened a village store to supply various staples to the local farming community. While there Oliver traveled 10 miles in all direction to look at mills. The mills he visited were usually small stone or wood structures where a single water wheel operated a single pair of millstones. The bolting of ground grains was often done by hand with a sieve in the mill's basement were it was dark, cold and damp. Sometimes a simple bolter was turned by water, sifting the coarse brown meal from the white flour. Evans was of course aware that people do not like to eat dirt if they could see it. If the flour fell onto the floor, people walked in it until eventually it all went into the flour barrel. The storage time for grain and especially ground flour was too long. Flour was stored to age and to whiten, which created a problem with additional contamination and insects.

Evans concluded that there was a great deal wrong with the milling industry. Grain was often contaminated before it came into the mill and was futher contaminated within the mill, because of storage on the floors as both grain and flour. Mill operation required too many men to make a product that was of very poor quality.

While Evans operated his store with his brother Joseph, he had the leisure to reflect on the distasteful, inadequate and antiquated methods he found employed in grist mills. After his marriage to Sarah Tomlinson on April 22, 1783, at Old Swedes Church in Wilmington, Delaware, they returned to Tuckahoe. There in the summer of 1783 he began working in his ideas for a mill elevator. First he built a paper model. The elevator was an endless band with wooden or sheet metal buckets or cups spaced about 12 inches apart on a belt moving over two pulleys. The top pulley was fixed to the upper floor and the lower one to the basement floor. It was all enclosed to protect the moving belt and ground grain. This elevator could elevate continouously, and thus lift three hundred bushels of grain or flour per hour. The old method was to hoist it up a tub full at a time, which was the sole work of two men.

By the end of September 1783, he had perfected the princlple for his hopper-boy. The hoppper-boy was a large revolving rake some twenty feet long, adjustable on a vertical shaft by means of a cord and a balance weight. It spead the ground flour after it was ground evenly on the upper floor (called the meal loft), gradually drying it of its mosture so it could be properly sifted. As the rake revolved in a circle on the floor, flour was delivered from a chute at the outer curcumference. Because of the angle of the sweeps on the bottom of the rake, the flour was gradually turned over and over as it moved towards the center. The hopper-boy guided it to a chute leading to the bolting hopper. The old method was for a boy (called the hopper-boy) to dump the flour on the floor and rake it back and forth with a rake to reduce its heat and moisture so it would not clog in the bolting screens. Then the cooled flour would have to be gathered up and carried to the bolter. Evans' new mechanical hopper-boy fit into his idea to construct a flour mill which could manufacture flour without intensive use of manual labor. The problem was no one paid any serious attention to his claims.

The advantages of Evans' elevator and hopper-boy were only aparent to himself. A year before his marriage, his two elder brothers, John and Theophilus, engaged him to build and equip a grist mill with his improved machinery, on the Faulkland Road where it crossed over Red Clay Creek about two miles from Newport Delaware. This mill was completed in September of 1785. At this time Evans also completed his invention of the conveyor, the drill and the descender. These five original inventions of Oliver Evans were applied to his idea of an automated milling process. Evans had patented his inventions, then two years later undertook to charge fees on installation of one or all his inventions in mills. The amount or charge depended on the number of millstones in a mill.

Oliver Evans wrote the following description on the process of making flour:


"If the grain be brought to the Mill by land carriage, the Miller took it on his back, a sack generally 3 bus., carried it up one story by stair steps, emptied it in a tub holding 4 bus., this tub was hoisted by a jack moved by the power of the Mill which required one man below and another above to attend to it, when up the tub was moved by hand to the granary, and emptied. All this required strong men. From the granary it was moved by hand to the hopper of the rolling screen, from the rolling screen by hand to the millstone hopper, and as ground it fell in a large trough, retaining its moisture, from thence it was with shovels put into the hoist tubs which employed 2 men to attend, one below, the other above, and it was emptied in large heaps on the Meal loft, and spead by shovels, and raked with rakes, to dry and cool it, but this necessary operation could not be done effectually, by all this heavey labour. It was then heaped up over the bolting hopper, which required constant attendance, day and night, and which would be fequently overfed, and passed through the cloth, which with the great quantity of dirt constantly mixing with the meal from the dirty feet of every one who trampled in it, trailing it over the whole Mill and wasting much caused great part to be condemned, for people did not even then like to eat dirt, it they could see it. After it was bolted it required much labour to mix the richest and poorest parts together, to form the standard quality, this lazy millers would always neglect, and great part would be scrapped or condamned, while others was above the standard."

In 1787 Oliver Evans advertised on a broadside his mill in Delaware:

"To the Millers."

"The subscribers have a Merchant-Mill on Red Clay Creek, 3 miles above Newport, New Castle County, Delaware, with Evans's new-invented Elevator and Hopperboys erected in her, which does the principal Part of the Work. One if the Elevators receives the Wheat at the Tail of the Wagon, and carries it up to the Garners, out of which it runs through Spouts into the Screen and Fan, through which it may be turned as often as necessary, till sufficiently cleaned, thence into a Garner over the Hopper which feeds the Stones regularly. Another Elevator receives the Meal when ground and carries it up, and it falls on the Meal-loft, where the Hopperboy receives it and spreads it aboard thin over the floor, and turns it over and over perhaps an hundred Times and cools it compleatly, then conveys it into the Boulting- Hopper, which it attends regularly; said Elevator also carries up the Tail Flour with a Portion of Bran, and mixes it with the ground Meal to be boulted over, by which means the Boulting is done to the greatest Perfection possible, and the Cloths will be keppt open by the Bran in the hottest Weather without Knockeers. All this is done without Labour, with much less Waste, and much better than is possible to be done by Hand, as the Miller has no need to trample in the Meal, nor any way to handle or move it from the Time it leaves the Waggoner's Bag, until it comes into the Superfine Chest ready for Packing. The whole Expence of the Materials and and erecting said Machinery will not exceed from Twenty to Forty Dollars, as the Mills may differ in Construction. One Hand can now do the Work that used to employ two or three, two Hands are able to attend a Mill with two Waterwheels and two Pair of Stones steady running, with very little Assistance, if the Machinery be well applied. They are simple and durable, and not subject to get out of Repair. If Millers will think on this when they are fatigued carrying heavy Bags, or with hoisting their Wheat or Meal, spreading to cool, and attending the Boulting-Hopper, Screean and Fan, and when they see the Meal scatered over the Stairs, & etc., wasting, or when they hoist their tail Flour with the Bran to boult over and when their Flour is scraped for neglect in Boulting, and when the Superfine is let run into the Middlings by over feeding, & etc., and consider that these Machiners will effectuall remedy all this, and save great Experence in Wages, Provisions, Brushes and Candles, and he may conclude that it is not best to continue in the old Way, while such excellent Improvements are extant. Those who chose to adopt them, may have Permission, with full Directions for erecting them, by applying to OLIVER EVANS, the inventor, who has an exclusive Right, or to either of the Subscribers. JOHN, THEOPHILUS, & OLIVER EVANS."

"N. B. Farmers and others may have Wheat ground during the Winter Season at said Mill (on good Burrs and all Things in the best Order) with great Care and Dispatch, at the low Rate of Thirty Shillings per 100 Bushels, or Eighteen Shillings per Load. Red Clay Creek, Dec. 19, 1787."

Part 2 will continue with Oliver Evans and his 1795 publication of The Young Mill-Wright's and Miller's Guide, which details and describes the construction of devices to overcome the heavy labor in the flour trade and reduce the manpower needs. This book is the first practical technical manual for the milling trade. And this in many ways was the first how-to book on any trade subject. As it went through its 15 editions until 1860, other technical manuals written for other trades began to appear.

o The Automation of Flour Milling in America, Part 2

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Copyright 1996 by T. R. Hazen