On 16 June, the charcoal kiln at the Warburg Reserve, Oxfordshire was unloaded and its charcoal removed. The firing had included the wooden chair and sections of wood which were part of my artistic research into charcoal making and its possibilities.
I’d photographed the loading of the charcoal kiln on 26 May. Now was the unloading.
When I arrived at the kiln, its lid had been removed and people dressed in paper suits, eye protection and respirators were busy empting it. The scene looked apocalyptic! Quite different to the stacking of cut wood in the kiln along with my research items prior to firing. The dust from the charcoal and ash in the kiln presented a hazard to the people working there and hence the protective equipment.
Making charcoal fuel
Beside the open charcoal kiln, there were two ‘workstations’. The charcoal was lifted out of the kiln with a fork and put onto a workbench where the large lumps of charcoal where broken in small ones.
Then it was transferred to a trommel which graded out the smaller pieces of charcoal. The smaller graded out charcoal know as ‘pea’, is retained for the next firing.
The lump wood charcoal was then bagged up, and weighed – making it ready to be distributed and sold. A neat line of bags was the end of the ‘production line’.
The result of the charcoal finishing, is a uniform lump wood charcoal for use as a fuel for barbecues, cooking and heating.
There are also industrial uses for charcoal. Charcoal burns at very high temperatures (up to 1,760°C) when air is blown through it, and this is sufficient to smelt iron ore. Prior to mineral ores like coal being used for smelting – like today – then charcoal was used.
There was some wood in the kiln post firing which was not completely burned (pyrolysed) and this was set aside into baskets for the next time. Unburnt wood is known as ‘browns’ if they have brown tars on their surface. The inside of the kiln was also coated with these tars too.
My research items
My research items – the flat-pack chair and sections of wooden log were wrapped in foil and chicken wire. This helped in identifying them amongst the heap of charcoal and ash. Even if the items are very fragmented, at least I will have all the fragments for the next part of my research.
Thank-you to BBOWT for allowing me to photograph their kiln at Warburg.