Malt Kilns and Malthouses

How Malt is made

To understand the buildings which make up a maltings, it is necessary to understand how malt was produced.

Malt is artificially germinated grain, usually but not exclusively barley, and is a main ingredient in the production of beer. The process starts with the cleaning of the grain of any rubbish such as small stones. The grain is then soaked (‘steeped’) in water which encourages germination to begin. This first stage is sometimes referred to as ‘growing’, to produce a rootlet (but not a shoot), at which point the starches in the grain will be turning to sugars. It is at this critical stage that further germination, which takes place on an unheated open floor, is arrested by drying the grains in kilns. Once kilning is complete the malt is cleaned of its rootlets and is ready for use in brewing.

In Britain, for much of the last 2000 years, kilning has taken place in specially designed structures, the designs of which have changed over that time.

From malt kilns as excavated structures to standing buildings

Remains of kilns have been found dating from the prehistoric and Roman periods. As few examples remain in situ, understanding them is best done from excavation reports. These early kilns are often referred to as corn driers, but probably they would have been primarily used for kilning malt. Certainly, they could have been used for drying corn, but if so, then it is more likely, they were used just prior to milling, in the same way that some corn mills in Scotland and western England had kilns attached to them. Evidence from experiments has shown drying grain for storage was not practical.

There are variations in design in these early kilns, with some kilns having solid floors over flues whereas in others the flue leads to a pit. The more common type, the solid floor kiln, had T-shaped flues, and examples of this have been found at Beck Row, Mildenhall, Suffolk, and Frocester, Gloucestershire. It would appear that pit kilns became more common in the medieval period , although some solid floor kilns were still used. Pit kilns took the form of either an inverted pyramid or cone. In these the combustion gases from the fire went through a non-solid floor. Good examples of medieval pit kilns were found at Kimberley, Nottinghamshire, and at Barrow in Rutland.

Documentary sources for early malt kilns and malthouses rarely give much detail on the structures in which malt was produced. The change over from pit kilns to the type with a fixed spark plate probably occurred in the later 16th century. Evidence for this comes from the physician, John Caius. In 1556 he published an account of brewing and malting which included a description of the kiln as a vaulted furnace which had vents on all sides so that the heat could circulate to an upper level where the grain was dried. A good example is at Mansfield Woodhouse, Nottinghamshire, dating from the eighteenth century. This type of furnace continued in use well into the 19th century.

It is also from the 16th century that recognisable malthouse buildings survive. The earliest securely dated example is Boyes Croft, Great Dunmow, Essex, although it is only the middle section which is of that date (from 1512 onwards).

From then on maltings as buildings become more recognisable, often by their kilns but also by small regularly-spaced windows, often in every other bay: good light was not a requirement for a malthouse. Good examples of the type can be found at Chipping Campden, Gloucestershire (of stone), and at Cropwell Butler, Nottinghamshire (of brick). This latter building does not have an evident kiln but the characteristic windows indicate its original use as a malthouse.

An 18th century example with kilns is at Stowmarket, Suffolk.

Malthouses and kilns from the 18th century onwards

The layout of malthouses changed little after the 18th century. The malthouse included separate barley and malt storage areas and a rectangular steeping cistern of stone or brick, usually on the bottom floor, although as the 19th century progressed it might be found on a middle floor of a three-floor maltings. The germination section of the building was still a large open space, the barley being spread over the floor and regularly turned by hand to encourage germination. The kiln still had a furnace on the ground floor and a drying floor above, the floor being often of perforated ceramic tiles but sometimes of woven wire. Later in the 19th century wedge wire gained prevalence.

Externally the fenestration generally remained as in earlier periods: regularly-spaced small windows for the germination areas, and limited or no windows for storage areas. Kilns increasingly had distinctive pyramidal or cone-shaped roofs surmounted by a cowl, and are often prominent features of urban and rural landscapes.

Later in the 19th century there were also further changes. It became more common for a specialist architect to design a maltings, especially large ones. There was an increasing use of power, not primarily steam but more often gas and later oil engines. This enabled the greater use of machinery to move the bulky materials from stage to stage in production. Generally, equipment became more mechanised instead of being hand-operated. Kiln furnaces in newly built maltings were more likely to be supplied by specialist manufacturers such as Robert Boby of Bury St Edmunds, Suffolk, or H. J. H. King of Nailsworth, Gloucestershire.

The most important change came in 1880 with the repeal of the malt tax. Before the repeal of the malt tax, steeps had to be flat bottomed to comply with the legislation. Repeal enabled the use of hopper-bottomed steeps placed on upper floors as opposed to flat-bottomed ones on lower floors.

Floor malting continued to be the dominant means of producing malt until the second half of the twentieth century. However, increasingly a new method of production was introduced. Pneumatic malting, first developed in the late nineteenth century, enabled the more precise control of temperature and moisture in the germination stage of the process and reduced labour costs. Initially pneumatic malthouses retained the distinctive features of a maltings, most notably a kiln, but this method of malting eventually led to fewer identifying features in the exteriors of the buildings, with perhaps just a flat kiln cowl. Pneumatic malting ultimately led to the abandonment of floor malting, and many earlier malthouses were either demolished or turned to new uses.

The Future is Reuse

Malthouses are usually not easy to reuse, generally having low floor heights and poor lighting. Reusing large malthouses for residences can mean the loss of a floor to increase head heights, the subdivision of the malting floors and the insertion of windows in otherwise blank bays. Steeps and kiln furnaces are usually lost, as neither fit easily within converted buildings. A kiln furnace can, however, form a feature in a small residential conversion, for example at Malthouse No 4 in Weymouth , where a kiln has been retained.

Commercial reuses may be less intrusive because they can retain large undivided spaces, but are rarely secure in the long-term. Cultural reuses may work better, but again internal features may be lost although exterior features can more easily be retained. The Maltings Theatre at Ely, Cambridgeshire, for example, fits comfortably inside the late-19th century building, largely unaltered externally.

Given that the majority of people will only be seeing the exterior of maltings, it is perhaps more important that exterior features such as fenestration and kilns are retained. Nevertheless to understand what might be lost it is important to fully understand malthouses and their kilns from all periods, and retain internal features where possible.

Further information

Patrick, A. ‘Establish a Typology for the Buildings of the Floor Malting Industry’ (Industrial Archaeology Review, Volume XVIII Number 2 1996) 180-200.

Patrick, A et al, 2004: Strategy for the Historic Industrial Environment Report No 1 –Maltings in England. 

Reynolds, P J, and Langley, J K ‘Romano-British Corn-Drying Oven: An
Experiment’. (Archaeological Journal No 136, 1979) 27–42.

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