Everything about Grist Mill totally explained
A
gristmill or
grist mill is a building where
grain is ground into
flour, or the grinding mechanism itself. In many countries these are referred to as
corn mills or
flour mills.
History
Early history
The first
water powered gristmills in
Europe were built toward the end of the first century BC. The first written account is that of
Strabo, describing the mill at
Cabira, in operation in 63 BC. These mills had horizontal wheels. Vertical wheels were in use in the
Roman Empire by the end of the first century BC, and these were described by
Vitruvius. The peak of Roman technology is probably the
Barbegal aqueduct and mill where water with a 19-meter fall drove sixteen water wheels, giving a grinding capacity estimated at 2.4 to 3.2 tonnes per hour. Water mills seem to have remained in use during the post-Roman period, and by 1000 AD, mills in Europe were rarely more than a few miles apart. 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 around 17,000 by 1300.
Limited examples of gristmills can be found in
Europe from the
High Middle Ages. An extant well-preserved
waterwheel and gristmill on the
Ebro River in
Spain is associated with the
Real Monasterio de Nuestra Senora de Rueda, built by the
Cistercian monks in 1202. The Cistercians were known for their use of this technology in Western Europe in the period 1100 to 1350.
The classical British and American mills
Classical mill designs are usually
water powered, though some are
wind mills, or powered by
livestock. A
sluice gate is used to open a channel and so start the water flowing and a
water wheel turning. In most such mills the water wheel was mounted vertically, for example, edge-on, in the water, but in some cases horizontally (the
tub wheel and so-called
Norse wheel). Later designs incorporated horizontal
steel or
cast iron turbines and these were also sometimes refitted into the old wheel mills.
In most wheel-driven mills, a large
gear-wheel called the
pit wheel is mounted on the same axle as the water wheel and this drives a smaller gear-wheel, the
wallower, on a main
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 10
rpm, or so.
The millstones themselves turn at around 120 rpm. They are laid one on top of the other. The bottom stone, called the
bed, is fixed to the floor, while the top stone, the
runner, is mounted on a separate spindle, driven by the main shaft. A wheel called the
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 going 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 grain is lifted in
sacks onto the
sack floor at the top of the mill. The sacks are emptied into bins, where the grain falls down through a hopper to the stones on the
stone floor below. The flow of grain is regulated by shaking it along a gently sloping trough (the
slipper) from which it falls into a hole in the center of the runner stone. The milled grain (flour) is collected as it emerges through the grooves in the runner stone from the outer rim of the stones and it gets fed down a chute to be collected in sacks on the ground or
meal floor. A very similar process is used for grains such as
wheat,
kamut, etc to make flour as well as for
maize to make
corn meal.
In order to prevent the vibrations of the mill machinery from shaking the building apart, a gristmill will often have at least two separate foundations.
American inventor
Oliver Evans revolutionized this labor-intensive process. At the end of the eighteenth century he patented and promoted a fully automated mill design.
The
Boykin Mill, in
Boykin, South Carolina, has an operating grist mill where meal and
grits have been ground by
water power the same way for over 150 years.
Image:Flour mill 20050723 001.jpg|Old fashioned flour mill
Image:Gristmill Hopper 1938.gif|Gristmill hopper, Skyline Drive, VA, 1938. Grain was funneled through the hopper to a grinding stone below.
Image:Grinding Corn Usquepaugh RI 1940.jpg|Corn over the grinding stone in Kenyon's johnnycake flour mill in Usquepaugh, RI, (near Kingston) 1940
Image:Thomas Mill Basement Chester Co PA.jpg|Gristmill drive machinery, Thomas Mill, Chester County, PA
Image:Pedal-wheat-mill.jpg|Pedal powered wheat mill, Shediac Cape, New Brunswick
Image:foundations.jpg|Remnants of some of the scores of flour mills built in Minneapolis between 1850 and 1900. Note the underground Mill race that powered mills on the west side of the Mississippi River at St. Anthony Falls.
Image:Phelpsmill ottertailcounty.jpg|Phelps Mill in Otter Tail County, Minnesota
Image:Sturbridgemill.jpg|Wheel of the 1840s-era Grist Mill at Old Sturbridge Village in Sturbridge, MA.
Image:Mt_Vernon_Gristmill_Slipper.jpg|"Slipper" feeding corn into the grindstones of George Washington's Grist Mill.
Modern mills
Historically, gristmills contained rotating
stones powered by
water or by
wind; later mills used
steam engines for power, and modern mills typically use
electricity or
fossil fuels to spin heavy
steel rollers. These techniques produce visibly different results, but can be made to produce nutritionally and functionally equivalent output.
Gristmills only
grind clean grains, that is, grain from which stalks and
chaff have previously been removed, but some mills also housed equipment for
threshing, sorting, and cleaning prior to grinding. Gristmills also grind corn into meal.
Modern mills are almost certainly "merchant mills", that is, they're privately owned and accept money or trade for milling grains, or the corporations that own the mills buy unmilled grain and then own the flour produced. Early mills were almost always built and supported by farming communities and typically a percentage of each farmer's grain called a "miller's toll" was set aside for the miller in lieu of wages. Although
gristmill can refer to any mill that grinds grain, the term historically was used to refer to a local mill where farmers brought their own grain and received the flour from it, minus the "miller's toll." Modern mills use serrated and flat
cast iron 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 wheat or
graham flour.
List of historic gristmills
United States
Notable functioning gristmills
- Glade Creek Grist Mill in Babcock State Park, West Virginia
- Jenney Grist Mill, Plymouth, Massachusetts
- Kymulga Mill, Childersburg, Alabama
- Grist Mill at Old Sturbridge Village, Sturbridge, Massachusetts
- West Point Mill, Durham, North Carolina
- Mingus Mill, Sevier County, Tennessee
- Cooper Mill, Chester, New Jersey
- Newlin Grist Mill, Glen Mills, Pennsylvania
- War Eagle Mill, Rogers, Arkansas
- Stony Brook Grist Mill, Stony Brook, New York
- Carpenter's Grist Mill, Perryville, RI
- Old Mill at Berry College, Rome, GA
- Dexter Grist Mill, Sandwich, Massachusetts
- Kings Landing Historical Settlement, New Brunswick, Canada
Others (ruins, remnants, partially preserved)
Audra State Park, West Virginia
Causey's Mill, Virginia
Valley Falls State Park, West Virginia
United Kingdom
see Watermills in the United Kingdom (a list).
Further Information
Get more info on 'Grist Mill'.
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