Discover how Winchester City Mill works

Exterior of Winchester City Mill, Hampshire, with the river running underneath. — Exterior of Winchester City Mill | © National Trust Images/Oskar Proctor

Discover a milling tradition hundreds of years old which can produce English wheat flour at a rate of 20-30kg per hour. This happens when wholegrain seed is passed between millstones and ground down before being sifted into bags.

The hopper

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

The damsel

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

The bell and horse

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.

Volunteer wearing a cap and apron works with wooden machinery, overseeing the flour-making processes at Winchester City Mill, Hampshire — Volunteer overseeing the flour-making processes at Winchester City Mill, Hampshire | © National Trust Images/William Shaw

The runnerstone and bedstone

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

Bagging up the flour

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

Freshly ground flour falling from a chute at Winchester City Mill, Hampshire — Freshly ground flour falling from a chute at Winchester City Mill | © National Trust Images/William Shaw

The waterwheel

Winchester City Mill houses one undershot waterwheel, 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 seven or eight revolutions per minute.

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

Controlling the water

The waterwheel 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 millstones on the stone floor. Raising the gate allows water to pass under the waterwheel. The height of the sluice gate determines how much water hits the wheel and consequently the speed of the mill.