Gristmill

Source: Wikipedia, the free encyclopedia.
Several terms redirect here. For other uses, see Cornmill (disambiguation) and Flour Mill (disambiguation).
Allied Mills flour mill on the banks of the Manchester Ship Canal in North West England

A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and middlings. The term can refer to either the grinding mechanism or the building that holds it. Grist is grain that has been separated from its chaff in preparation for grinding.

History

Early history

Main article: Watermill
See also: List of ancient watermills and List of early medieval watermills
Senenu Grinding Grain, c. 1352–1336 BC. The royal scribe Senenu appears here bent over a large grinding stone. This unusual sculpture seems to be an elaborate version of a shabti, a funerary figurine placed in the tomb to work in place of the deceased. Brooklyn Museum.
The basic anatomy of a millstone; this diagram depicts a runner stone.
Grinding mechanism in an old Sweden-based flour mill
The old water mill at Decew Falls in St. Catharines in Southern Ontario

The Greek geographer

Asia Minor, before 71 BC.[1]

The early mills had horizontal paddle wheels, an arrangement which later became known as the "

bed", a stone of a similar size and shape.[2] This simple arrangement required no gears, but had the disadvantage that the speed of rotation of the stone was dependent on the volume and flow of water available and was, therefore, only suitable for use in mountainous regions with fast-flowing streams.[2] This dependence on the volume and speed of flow of the water also meant that the speed of rotation of the stone was highly variable and the optimum grinding speed could not always be maintained.[2]

Barbegal aqueduct and mill where water with a 19-metre fall drove sixteen water wheels, giving a grinding capacity estimated at 28 tons per day.[7]
Water mills seem to have remained in use during the post-Roman period.

Manually operated mills utilizing a crank-and-connecting rod were used in the

Western Han dynasty.[8]

There was an expansion of grist-milling in the

Bilbays had a grain-processing factory that produced an estimated 300 tons of flour and grain per day.[12]

From the late 10th century onwards, there was an expansion of grist-milling in Northern Europe.[9] In England, the Domesday survey of 1086 gives a precise count of England's water-powered flour mills: there were 5,624, or about one for every 300 inhabitants, and this was probably typical throughout western and southern Europe. From this time onward, water wheels began to be used for purposes other than grist milling. In England, the number of mills in operation followed population growth, and peaked at around 17,000 by 1300.[13]

Limited extant examples of gristmills can be found in Europe from the

Cistercian monks
in 1202. The Cistercians were known for their use of this technology in Western Europe in the period 1100 to 1350.

Classical British and American mills

Wayside Inn Grist Mill in Massachusetts
Stretton Watermill, a 17th-century operational mill in Cheshire, England

Although the terms "gristmill" or "corn mill" can refer to any mill that grinds grain, the terms were used historically for a local mill where farmers brought their own grain and received ground meal or flour, minus a percentage called the "miller's toll."[14] Early mills were almost always built and supported by farming communities and the miller received the "miller's toll" in lieu of wages. Most towns and villages had their own mill so that local farmers could easily transport their grain there to be milled. These communities were dependent on their local mill as bread was a staple part of the diet.

Classical mill designs are usually

turbines
and these were sometimes refitted into the old wheel mills.

In most wheel-driven mills, a large gear-wheel called the

driveshaft running vertically from the bottom to the top of the building. This system of gearing ensures that the main shaft turns faster than the water wheel, which typically rotates at around 10 rpm
.

The millstones themselves turn at around 120

stone nut connects the runner's spindle to the main shaft, and this can be moved out of the way to disconnect the stone and stop it turning, leaving the main shaft turning to drive other machinery. This might include driving a mechanical sieve
to refine the flour, or turning a wooden drum to wind up a chain used to hoist sacks of grain to the top of the mill house. The distance between the stones can be varied to produce the grade of flour required; moving the stones closer together produces finer flour.

The grain is lifted in sacks onto the sack floor at the top of the mill on the

corn meal
.

In order to prevent vibrations from the millstones shaking the building apart, they were usually placed on a separate timber foundation, not attached to the mill walls, known as a husk. This foundation isolated the building from vibrations coming from the stones and main gearing and also allowed for the easy re-leveling of the foundation to keep the millstones perfectly horizontal. The lower bedstone was placed in an inset in the husk with the upper runner stone above the level of the husk.

The automatic mill

A grist mill, c. 1880

American inventor Oliver Evans revolutionized the labor-intensive process of early mills at the end of the eighteenth century when he automated the process of making flour. His inventions included the Elevator, wood or tin buckets on a vertical endless leather belt, used to move grain and flour vertically upward; the Conveyor, a wooden auger to move material horizontally; the Hopper Boy, a device for stirring and cooling the newly ground flour; the Drill, a horizontal elevator with flaps instead of buckets (similar to the use of a conveyor but easier to build); and the Descender, an endless strap (leather or flannel) in a trough that is angled downward, the strap helps to move the ground flour in the trough. Most importantly, he integrated these into a single continuous process, the overall design later becoming known as the Automatic (or Automated) mill. In 1790 he received the third Federal patent for his process. In 1795 he published "The Young Mill-Wright and Miller’s Guide" which fully described the process.[15]

Evans himself did not use the term gristmill to describe his automatic flour mill, which was purpose designed as a merchant mill (he used the more general term "water-mill"). In his book his only reference to "grist" (or "grists") is to the small batches of grain a farmer would bring in to have ground for himself (what would be generally called barter or custom milling). In his book, Evans describes a system that allows the sequential milling of these grists, noting that "a mill, thus constructed, might grind grists in the day time, and do merchant-work at night."[16] Over time, any small, older style flour mill became generally known as a gristmill (as a distinction from large factory flour mills).

Modern mills

Interior in Tartu Mill, the largest grain milling company in the Baltic states
Pilgrim's Pride feed mill in Pittsburg, Texas, August 2015

Modern mills typically use electricity or

fossil fuels to spin heavy steel, or cast iron, serrated and flat rollers to separate the bran and germ from the endosperm. The endosperm is ground to create white flour, which may be recombined with the bran and germ to create whole grain or graham flour. The different milling techniques produce visibly different results, but can be made to produce nutritionally and functionally equivalent output. Stone-ground flour is preferred by many bakers and natural food advocates because of its texture, nutty flavour, and the belief that it is nutritionally superior and has a better baking quality than steel-roller-milled flour.[17] It is claimed that, as the stones grind relatively slowly, the wheat germ is not exposed to the sort of excessive temperatures that could cause the fat from the germ portion to oxidize and become rancid, which would destroy some of the vitamin content.[17] Stone-milled flour has been found to be relatively high in thiamin, compared to roller-milled flour, especially when milled from hard wheat.[17]

Gristmills only grind "clean" grains from which stalks and chaff have previously been removed, but historically some mills also housed equipment for threshing, sorting, and cleaning prior to grinding.

Modern mills are usually "merchant mills" that are either privately owned and accept money or trade for milling grains or are owned by corporations that buy unmilled grain and then own the flour produced.

Pests

One common pest found in flour mills is the Mediterranean flour moth. Moth larvae produce a web-like material that clogs machinery, sometimes causing grain mills to shut down.[18]

Gallery

See also

References

  1. ^ Wikander 1985, p. 160; Wikander 2000, p. 396
  2. ^
    ISBN 978-0-8018-8586-0
    . Retrieved 15 December 2009. norse wheel.
  3. ISBN 90-277-1693-5. ASIN 9027716935
    .
  4. ^ Bradley, Keith R. Apuleius and Antonine Rome: Historical Essays. p. 68.
  5. ^ Welborn, L.L. Paul, the Fool of Christ. Bloomsbury. p. 75.
  6. ISBN 9781118451366
    .
  7. ISBN 9781317761570
    .
  8. ISBN 978-1-4020-9484-2
    .
  9. ^
    ISBN 9781317761570
    .
  10. ISBN 978-0-415-12410-2
    . : 781 
  11. ISBN 90-04-14649-0
  12. ISBN 9781317761570
    .
  13. ^ Gimpel, J., The Medieval Machine, Gollanz, 1976, Chapter 1.
  14. ^ "ARTFL Project: Webster Dictionary, 1913". The University of Chicago - Department of Romance Languages and Literature. Archived from the original on 2007-03-13. Retrieved 2006-09-28.
  15. ^ "Old Stone Mill - History of the Old Stone Mill".
  16. ^ Evans, Oliver, The Young Mill-Wright and Miller’s Guide, Oliver Evans, Philadelphia, 1795, Chapter II, pp.88-90
  17. ^ a b c Campbell, Judy; Mechtild Hauser; Stuart Hill (1991). "NUTRITIONAL CHARACTERISTICS of ORGANIC, FRESHLY STONE-GROUND, SOURDOUGH & - CONVENTIONAL BREADS". Ecological Agriculture Projects Publications. Ecological Agriculture Projects. Archived from the original on 18 February 2003. Retrieved 15 December 2009.
  18. ^ "Mediterranean Flour Moth (Department of Entomology)". Department of Entomology (Penn State University). Retrieved 2017-11-14.
  19. ^ "Mingus Mill in the Smokies - Grist Mill Near Cherokee NC".
  • Wikander, Örjan (1985). "Archaeological Evidence for Early Water-Mills. An Interim Report". History of Technology. Vol. 10. pp. 151–79.
  • Wikander, Örjan (2000). "The Water-Mill". In Wikander, Örjan (ed.). Handbook of Ancient Water Technology. Technology and Change in History. Vol. 2. Leiden: Brill. pp. 371–400.
    ISBN 90-04-11123-9
    .

Further reading

  • Richard Bennett & John Elton. History of corn milling (London, Simpkin, Marshall and company, 1898).

External links

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