Quern-stone

The upper stones were usually concave while the lower ones were convex. Quern-stones are frequently identifiable by their grooved working surfaces which enabled the movement of flour. Sometimes a millrind was present as a piece of wood (or other material), which 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.[4] 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.[5] 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.[6]

Revolving beehive quern-stones and [lower] a saddlestone on display at Cliffe Castle Museum, in Keighley, West Yorkshire.

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.

The use of grinding stones for vegetal food processing, and possibly the production of flour, was widespread across Europe from at least 30,000 years ago.[7]

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).[8]

Quern stones were used in China at least 10,000 years ago to grind wheat into flour. The production of flour by rubbing wheat by hand took several hours.[9] Due to their form, dimensions, and the nature of the treatment of the surfaces, they reproduce precisely the most ancient implements used for grinding cereal grain into flour. Saddle querns were known in China during the Neolithic Age but rotary stone mills did not appear until the Warring States Period.[10] A prehistoric quern dating back to 23,000 BCE was found at the Longwangchan archaeological site, in Hukou, Shaanxi in 2007. The site is located in the heartland of the northern Chinese loess plateau near the Yellow River.[11]

As well as grain, ethnographic evidence and Mesopotamian texts show that a wide range of foodstuffs and inorganic materials were processed using stone querns or mortars, including nuts, seeds, fruit, vegetables, herbs, spices, meat, bark, pigments, temper and clay.[12] Moreover, one study analysing quern-stones noted that a number of querns had traces of arsenic and bismuth, unlike their source rocks, and had levels of antimony which were ten times higher than those of the rocks. The authors concluded that this was probably due to the use of these querns in the preparation of medicines, cosmetics, dyes or even in the manufacture of alloys.[13]

Querns were widely used in grinding metals ores after mining extraction. The aim was to liberate fine ore particles which could then be separated by washing for example, prior to smelting. They were thus widely used in gold mining in antiquity.

In Shetland, tobacco was not smoked when first introduced, but instead was ground up into snuff, and inhaled up the nose. Snuff-querns consisted of an upper and lower stone, fixed together by a central iron pivot. The quern was held on the user's lap, the eye of the quern was filled with dried tobacco leaves, and then the upper-stone was turned using the handle. The friction caused by the turning ground the leaves into a fine powder that built up around the edge of the lower-stone. Many snuff-querns had a small hole or cut made near the edge of the upper-stone, into which a pointed end of a lamb's horn was placed in order to turn the stone; an alternative to using a handle.[14]

Youth grinding coffee on quern (Yemen, 1934)

A stack of quern-stones for sale in a market in Haikou, Hainan, China. These quern-stones are only about 30 cm wide.

There are, however, more surprising recorded uses of quern-stones. For example, DeBoer, in his review of the traditional gambling games of North American tribes, reports that one of the games involved bouncing a group of split canes off a quern.[15]

Violence is recorded thus in the Old Testament in the Book of Judges (9:53; NRSV): “But a certain woman threw an upper-millstone on Abimelech’s head, and crushed his skull.”

The saddle quern is produced by rocking or rolling the muller using parallel motions (i.e., pushing and pulling the handstone), which forms a shape looking like a saddle. These are the most ancient and widely used type of quern-stone and were superseded around the 5th to the 4th century BC by the more efficient rotary quern.[18] The handstones for saddle querns are generally either roughly cylindrical (not unlike a rolling pin) and used with both hands, or rough hemispheres and used with one hand. This provides a crushing motion, not a grinding action and is more suitable for crushing malted grain. It is not easy to produce flour from a saddle quern with unmalted grain. The muller is also referred to as a 'rubber' or 'mouler'.[19] Some pictorial examples may be found in the metate article.

As the name implies, the rotary quern used circular motions to grind the material, meaning both the quern and the handstone were generally circular. The handstone of a rotary quern is much heavier than that of saddle quern and provides the necessary weight for the grinding of unmalted grain into flour. In some cases the grinding surfaces of the stones fit into each other, the upper stone being slightly concave and the lower one convex.

Rotary Hand Quern at the Estonian Open Air Museum

Querns from the Whithorn Museum

In this type, the upper stone is hemispherical, or bun-shaped, with a central conical hopper to hold the grain that falls down a hole to the grinding surface. It is held in position with a pivot that fits into a central hole in the bottom stone. The upper stone also has a deep horizontal socket in its steep side in which to place the wooden peg used as a handle to rotate or oscillate the upper stone. This was the earliest type of rotary quern to appear in the British Isles. It arrived in Britain in the middle of the Iron Age (about 400-300 BC) and spread into the northern half of Ireland, probably from Scotland, some time after the 2nd century BC.[20]

A hand quern being operated[21]

The adjustable, discoid rotary quern has larger, flatter and more discoid stones than the beehive type. The lower stone was completely perforated. The long handle rotated in a shallow socket in the upper surface of the upper stone. They are thought to have originated in Spain 2,500 years ago[22] and appear to have arrived in maritime Scotland from about 200 BC with people who built the defensive homes known as brochs. This Iron Age type closely resembles the adjustable Highland quern still in use in historic times.[23]

The quern rests on the earasaid of the woman on the right, possibly to catch grain; she feeds the stone with grain from the bowl at her left. Woodcut from Thomas Pennant's 1772 book A Tour in Scotland.

Garnett in his 1800 tour of Scotland describes the use of a hand quern as follows: "The quern consists of two circular pieces of stone, generally grit or granite, about twenty inches in diameter. In the lower stone is a wooden peg, rounded at the top; on this the upper stone is nicely balanced, so as just to touch the lower one, by means of a piece of wood fixed in a large hole in this upper piece, but which does not fill the hole, room for feeding the mill being left on each side: it is so nicely balanced, that though there is some friction from the contact of the two stones, yet a very small momentum will make it revolve several times, when it has no corn in it. The corn being dried, two women sit down on the ground, having the quern between them; the one feeds it, while the other turns it round, relieving each other occasionally, and singing some Celtic songs all the time."[21]

Under 200 mm (7.9 in) in diameter and varying from roughly dressed to carefully worked, often with vertical handle sockets, a new class of querns has been identified having been overlooked in the past as weights, etc. In all respects they are like full sized quern stones and they show the typical wear signs that indicate that they were used for grinding small amounts of seeds, minerals or herbs. A suggestion that they may have been made as toys is thought to be unlikely.[24]

Other forms of quern-stone include hopper-rubbers and Pompeian mills, both used by the Romans. The larger rotary mills were usually worked by a donkey or horse via an extension arm of wood attached to the upper stone.

Querns utilizing crank-and-connecting rods were used in the Western Han Dynasty.[25]