The craft of charcoal burning is very ancient and one with its roots firmly planted in our local area. Due to the abundance of woodland and easy access to water, the Weald, along with parts of the Lake District and the west coast of Scotland, was significant in the iron industry, dating back as far as the Bronze Age, and therefore also home to many charcoal burning operations.
The iron industry relied heavily on charcoal for smelting iron ore due to charcoal’s high burn heat and high carbon content. Wood in its original state cannot burn to the temperatures needed for iron smelting due to the amount of water in its make up, and substances like coal release impurities, for example sulphur, which affect the composition of the metalbeing heated. Therefore, until Abraham Darby created coke in 1709, charcoal production was an integral part of the iron industry.
If you were a visitor to our Museum over the Bank Holiday Weekend, you may have been lucky enough to see Jon Roberts and our Interpretation Team, creating a charcoal burn. The fascinating process of charcoal making is one which remained more or less the same from the Bronze Age right through to the 1900s and a tradition we are keen to preserve here at at the Museum.
The process begins with the building of a kiln. Historically these kilns would have been 30 foot high and burn for more than a week, however Jon and the team used around three tons of wood to create theirs – just enough to support the Museum’s charcoal requirements for the year.
The kiln itself is a more organised version of a bonfire, with a hole down the middle which is filled with kindling and then covered in hay to control the flow of oxygen. Embers – often the ‘brown ends’ which didn’t make the cut during previous charcoal production – are then dropped down the middle to ignite the fire. This is done until the furnace is the right temperature to cook, but not burn, the wood – typically around 400’. Once going, the top of the kiln is capped with green sticks and turf to keep oxygen to a minimum and ensure the wood bakes instead of turning to ash.
Jon and the team watched their kiln burn constantly for around 24 hours, monitoring the colour and intensity of the smoke and keeping an eye on shrinkage. The wood does not burn evenly so they also needed to cover any holes which formed in the sides and create holes to allow more oxygen to areas which were not burning properly. Once satisfied the charcoal was cooked, they covered the kiln with earth to stifle the oxygen and put out the fire, the kiln was then left for a further 24 hours to cool down enough to be opened. Once opened the team worked quickly to spread the contents into one single layer to allow further cooling, dabbing out any fires which reignited. The charcoal they created will be used around the Museum including in the forge, bronze working classes and also herbal classes.
Because it was essential to watch burning kilns both night and day, historic charcoal burners lived on site in groups with their families. However, charcoal burning was a well-paid occupation and workers often had nice houses they lived in when not working. The camp at the Museum was originally built by Mr and Mrs Langridge, two retired charcoal burners from Kingsfold, near Horsham. The simple structure of the huts, with turf sacking over a pole frame, follows a very old tradition.
In addition to iron smelting, over the years charcoal has had many uses, with different woods good for different things. For instance, a dense wood like oak or hornbeam creates charcoal which burns for a long time and so is good for use in furnaces, whereas willow has a beautifully consistent texture and therefore is frequently used as a drawing charcoal. Traditionally only the very wealthy would have been able to use charcoal for cooking, however more recently – due to its smokeless burning – it was used to cook on the front line during the First World War. Today the biggest use for charcoal is in filters for anything from water purifiers to cooker hoods.
Jon and the team worked with the wood available to them at the Museum and so created charcoal made from hazel, ash and sycamore. These medium density hardwoods are good allrounders which give strong, consistent heat when burned – perfect for our needs here at Weald & Downland Living Museum.