Milling and making flour at Winchester City Mill

Winchester City Mill Milling once again

Rebuilt in 1743 on a medieval site, Winchester City Mill remained in use until the early 20 Century. After an ambitious restoration project, the Mill resumed grinding flour in March 2004.

The history of making flour

If you want to make bread, biscuits or cakes, you first have to make flour, by grinding grain or cereal.

Early quern stones and Rotary querns

Quern stones, stone tools for hand grinding, were first used during the Stone Age to grind cereal grains (such as barley, oats, rye and wheat) and nuts and other vegetable food products for eating. One of the earliest forms of quern stone was the ‘saddle’ quern. People put the grain on a big flat stone (‘quern’) and rubbed it backwards and forwards will a small stone (‘handstone’)

They had to spend 5 hours every day just grinding grain to make enough flour to feed their families.

The rotary quern was invented during the fifth to third centuries BC. As the name implies, the rotary quern used circular motions to grind materials. The handstone of a rotary quern is much heavier than that of a saddle quern and provided the necessary weight for the grinding of grain into finer flour.

Mills and mill stones

As the demand for flour grew and populations increased, there needed to be a more efficient method of producing flour. But bigger stones meant they were too heavy to turn by hand. Initially, some places used donkeys, horses or slaves. With time, where there was a good river, watermills were built.

These water-powered mills were common by Roman times and used much larger circular-shaped stones; mill stones. These produced a finer flour than that produced by hand-held tools.

Many mill stones in Britain are made with hard-wearing quartz from France and, although expensive, they lasted for 50 years or more. They are not cut from one piece but built up from sections of quartz, cemented together with plaster and bound with iron bands.

Winchester City Mill’s mill stones were made by a specialist manufacturer in Holland in 2007 and contain quartz and basalt to give the same performance as French stones.

Mill stones are not flat underneath. Grains of cereal are very tough and if the stones were flat the grains would just roll between them. So each mill stone has a series of special grooves (‘furrows’) cut in to its surface. When paired with another mill stone, the grooves make a kind of scissoring motion creating the cutting or grinding function of the stones. The grooves are also at an angle so that when the mill stone turns, the flour is pushed towards the outside and is squeezed out.

How Winchester City Mill works - the grinding process

We mill English wheat and produce 20-30kg of flour per hour. Our mill stones only produce wholemeal flour as the whole grain seed passes between the stones. Historically, millers sieved the flour to produce whiter grades for the wealthy.

The stone floor

A diagram of Winchester City Mill's milling equipment on the stone floor
Stone floor milling equipment at Winchester City Mill, National Trust, Hampshire

The grinding process begins when the miller empties the sacks of grain down the wooden chute into the hopper above the mill stones. The shoe under the hopper shakes the grain into the centre of the top ‘runnerstone’

The damsel, which protrudes from the centre of the stone and rotates at the same speed as the mill stone, strikes against the shoe causing it to shake. Thus, the flow of grain increases as the speed of the mill increases.

The bell, fixed to the horse, provides a warning if the hopper becomes empty. Should this happen, the stones would run without grain and flour between them leading to rapid wear and damage.

The grain passes between the runnerstone and the lower ‘bedstone’ and is ground in to flour. The stones rotate at 60 revolutions per minute or above to mill high quality flour.

Finally, the flour passes down a second chute to the lower floor where it is collected in sacks.

The lower floor

This diagram shows how the mill machinery on the lower floor works together to grind the grain to flour
A diagram of Winchester City Mill's water wheel and gearing, Hampshire

Winchester City Mill houses one undershot water wheel, in the left-hand millrace. It is the source of power for the Mill’s flour grinding and is driven by the force of the River Itchen striking the wooden paddles. It makes about 7 or 8 revolutions per minute.

The series of gears connects the water wheel to the millstones and enables the mill stones to turn much faster than the wheel.

The water wheel can only turn, and milling commence, when the sluice gate is raised. You can see the controls for the sluice gate by the wall near the mill stones on the stone floor. Raising the gate allows water to pass under the water wheel. The height of the sluice gate determines how much water hits the wheel and consequently the speed on the mill.