Keston Windmill is a preserved post mill in complete mechanical and structural condition. As such, it is arguably the finest surviving example of its kind in the south east of the country. The mill is a Grade1 listed building. It ceased work almost a century ago; nearly all its machinery and fittings have survived from this lost era.

Important survivals include the two pairs of millstones; the internal timber binning; the flour dressing machine (or “bolter”) and the cleaning machine or “jog scry”. This last item is likely to be unique in the region. Several working parts have been carefully dismantled from their original positions and stored in the mill.

The top of the mill is over 450 feet above sea level. The structure is a Post Mill based on a roundhouse (brick built with a timber roof) and dates from around 1716. The whole of the upper part of the mill rests on a massive oak centre post rising out of the roundhouse and was rotated by the miller in order to ensure that the sails faced the wind.
A severe wind hit the mill in 1878 and damaged the sails. Re-starting the business was uneconomic but the mill has been restored twice since then. However, the sails were not replaced on the stocks as they would cause undue strain on the structure.
The body comprises three floors; the top for grain and the other two for milling machinery. A pair of stones can be seen at second floor level – the bedstone and the runnerstone. The latter was driven from below by the great spur wheel in the ceiling of the first floor. This had wooden teeth to avoid the risk of sparks being produced by contact between moving metal parts.
Corn was taken by sack hoist to the top of the mill and placed in the grain bin.
The grain then went through a chute to the hopper above the millstone.
Grain trickled from the hopper to the feed shoe which fed the particles onto the centre of the runnerstone.
Only this stone revolved and there was no contact with the bedstone below although the gap was minute and was controlled to vary the production of meal.
As the grain was ground it was expelled around the edge of the stone.
Meal fell into the meal spout and finally to the bin on the floor below.
We hope you enjoyed your visit.