Acorn Bank Watermill Trust

Mill Stones

Millstones are always in pairs – a lower or "bedstone", which is fixed, and an upper "runner" which rotates. Two pairs of stones can be run from each waterwheel. Acorn Bank Watermill has four pairs of stones, only one of which is operational that we use at the moment to grind wheat.

From the north Midlands northwards, milling had traditionally used stones cut from millstone grit, a hard rock found in many parts of the Pennines. Stones could be cut from a single block, but they tended to shred the bran and husks of wheat very finely; this meant that the bread made from the flour tended to be darker. The stones also wear quickly which means the flour contains more grit and also that they need to be redressed frequently to maintain the grinding surface.

Originally all of the at Acorn Bank stones would have been made of gritstone and were used for milling oats. One of each pair is a pair of shelling stones to remove the husk from the oats; the output from these stones was then sieved and the resulting "groats" were then milled in the second pair of stones to make oatmeal.

Millstone grit stone

Millstone grit stone showing the dressing of the face of the stone

French burr stones are made from a river quartzite which is particularly hard. It came in smaller blocks and had to be built, jigsaw-like, to form a complete millstone. The stone was imported in pieces, often as ballast as this avoided paying import duty. The pieces were cut and assembled in Britain, often at the ports, cemented together and held with one or two iron hoops. The French Burr stones don't shred bran and husks meaning these can be sieved out and allowing 'white' bread, seen as superior, to be made. The burr was also harder and needed less maintenance, perhaps once every few months rather than weekly.

One of the pairs of stones at Acorn Bank is made from French Burr. Our runner stone, which is made from 17 pieces, carried a maker's name plate with the inscription "Cotton & Davies, 22 Cheapside, Liverpool" and we know that partnership was dissolved in early 1853. It is this pair of French Burr stones that we use today to grind wheat to make our flour.

French Burr stone

French Burr stone showing the jigsaw of pieces