Quern-stones

Quern-stones are stone tools for hand-grinding a wide variety of materials. They are used in pairs. The lower, stationary, stone is called a quern, while the upper mobile stone is called a handstone. The central hole is called the hopper and a handle slot enables the handstone to be rotated. They were first used in the Neolithic era to grind cereals into flour.

An old Gaelic proverb is "The quern performs best when the grindstone has been pitted."

The upper stones were usually concave whilst the lower was convex and sometimes a rind was present as a piece of wood etc that allowed the cereal etc to be added but still acted as a centering device. The upper stone sometimes had a cup shaped area around the hopper hole with a raised edge. Most handstones have a handle hole on the upper surface, however one class of quern-stones have a slot handle which indicates that a piece of wood was placed horizontally and protruded out from the edge so that the operator could turn the stone by standing and using a rod vertically. One class of upper quern-stones has from two to three sockets for the rod used to turn them and this is thought to reflect the need to reduce wear and tear by having alternative points of contact when in active use.

Quern-stones have been used by numerous civilizations throughout the world to grind materials, the most important of which was usually grain to make flour for bread-making. They were generally replaced by millstones once mechanised forms of milling appeared, particularly the water mill and the windmill, although animals were also used to operate the millstones. However, in many non-Westernised, non-mechanised cultures they are still manufactured and used regularly and have only been replaced in many parts of the world in the last century or so.

In early Maya civilizations the process of nixtamalization was distinctive in that hard, ripe kernels of maize (corn) were boiled in water and lime, thus producing nixtamal which was then made into unleavened dough for flat cakes by grinding with a handstone on a quern (metate).

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