Revitalization of the traditional craftsmanship of lime-making in Morón de la Frontera, Seville.

Element included in the UNESCO List since 2011. Nomination file: no. 00511. Registered as Good Safeguarding practices by UNESCO.

Historical notes:

The artisanal production of lime consists of calcining limestone in a traditional kiln, fuelled by firewood, until it is transformed into quicklime. In the region of Morón de la Frontera, a system of open-cast quarries and lime kilns developed, around which, some villages were founded at the end of the 18th century. Families of lime workers settled there, reaching a population of almost three hundred inhabitants in 1960. For several centuries and well into the 20th century, the craftsmen extracted the limestone from the local quarries, that they would later transform into lime. Each craftsman worked his share of the lime, transporting it successively to the kiln for firing, which was favoured in the mid-19th century by the construction of the Morón-Utrera railway

Kiln construction technique

The first phase of the work consists of preparing the continuous fuelling kiln, which comprises two central bodies: the firing vessel, buried two metres below ground level, which can have a diameter of six or seven metres and a height of seven or eight metres, and the gallery, built into the slope of the ground, which allows access from the surface of the kiln to the vessel’s feeding mouth.

The process begins by covering the walls of the vessel, a circular wall of limestone masonry bound with mud, with a subsequent layer of the same material, which can be up to fifty centimetres thick, known as caterfa. The caterfa has an insulating function, preventing heat loss during firing. The next stage of the work consists in ahornar (building the kiln), i.e. placing the stones inside the firing vessel. To this end, the lime burner splits the stones so that they reach the correct size.

The stones are placed dry and concentrically upwards along the walls of the vessel starting from the base, known as the poyo or poyete (stone bench), where the kiln vault will be fixed. The smallest stones are placed first, starting from the kiln mouth, next to which the lime burner must leave a hollow space in which to burn the wood, the caldera (boiler). To this end, a sort of dome is built by tracing decreasing concentric rows, which is closed with a large stone. To do this, the lime burner gets inside the kiln. Once the surface level is reached, the colmo (brim) is built, consisting of a truncated cone-shaped structure that protrudes from the ground level up to a height of two and a half metres, which is the part visible from the outside of the kiln, and in which air inlets are left, to make them serve to increase the air intake of the boiler. Finally, in the lower part of the oven, the pantallón (large screen) is built, a stone wall in which three openings are left.

Firing

Once the loading is complete, the kiln is fired in order to start the process of calcining the stone. The firing time lasts on average between fifteen and twenty days, depending on weather conditions. During the firing process, the kiln must be constantly monitored and fed, introducing wood and removing ash at intervals of approximately half an hour, in order to maintain an internal temperature of 1,000 degrees Celsius. After five or six days, the kiln reaches its maximum temperature, and the lime stones begin to melt into each other. Once the firing is complete, the mouth of the kiln is covered with a sheet of metal and left to cool for about a week.

Emptying

Once the kiln has cooled, the lime burner dismantles it to collect the lime that has formed inside. Normally, the amount of lime produced in each batch corresponds to two thirds of the total weight of the stones placed in the kiln.

Detalle boca del horno encendido. Photo: Antonio Martínez Abril. © Instituto Andaluz del Patrimonio Histórico