Earthburn at Elterwater
Making charcoal at Cylinders Wood July 2011
contributed by Brian Crawley November 2011
Charcoal has been made for centuries in the Furness (old Lancashire) area of Cumbria in particular for the smelting of the abundant iron ore found in the district. It was made in the woodlands that were managed by coppicing to produce the enormous quantities of wood demanded by the process. The smelting furnace at Backbarrow was still using charcoal up to 1926 when all other iron making in the country had changed to coke as a fuel. The main use for charcoal these days is barbecueing.
Traditionally the broadleaf wood was stacked vertically around the central 'motty peg' on a levelled platform in the wood, the 'pitstead'. The 'clamp' was covered with bracken and earth to allow only a minimum amount of air into the 'burn'. The motty peg was then removed and burning embers poured down the hole. When it was sure that it was lit the top was also sealed with bracken and earth. As an alternative to the motty peg we used a south of England vertical triangular column of sticks to form the 'flue'.
The 'earth-clamp' continued to burn - or smoulder, with its limited oxygen supply - through the next two nights, reducing to about half its original volume, giving off all its moisture and volatile materials but not getting hot enough to burn the residual charcoal. The process is technically called the destructive distillation of wood. Some patching of holes with turf or soil was necessary to maintain the integrity of the cover; nightshifts were organised to provide 24 hour surveillance.
After injecting with about forty gallons of water to cool the clamp by its conversion to steam and final exclusion of oxygen, the turf covering was removed and the resultant charcoal spread across the ground. Any product found to be still burning were sprayed with water to extinguish them. A few only partially burnt pieces of wood, 'brown-ends', were extracted. When it was all cool enough the product was loaded into plastic bags or the 'swill' (basket made from thin strips of oak). The dust and particles less than 10mm were sieved from the final scrapings, the British Standard for BBQ charcoal specifies that there must not be more than 7% of this size. The small sievings are known to have very beneficial horticultural properties 'Biochar'.
(The final stage before sale to the customer would be to bag into British Barbecue Charcoal bags with information about its source and how to best use it. Information on the bags outlines the environmental benefits of coppicing and the almost 'carbon-neutral' property of charcoal made from coppice woods when the newly growing 'springs' are re-absorbing the carbon dioxide released during the barbecueing. This contrasts strongly with the currently popular gas barbecues that are burning fossil fuel.)
We had placed a few tin cans filled with kindling sticks cut from a piece of willow trunk towards the outside of the clamp and these were retrieved at the end of the burn to provide a small quantity of artist's drawing charcoal.
Charcoal was also made by a 'more modern' process by burning wood in a horizontal oil drum with a slot along its length. The product from this burn was all sieved to more than 10mm and although it is much smaller than the earth-clamp charcoal it is still excellent for barbecues and much easier to make!
The charcoal that would have been made at that site in the past for the gunpowder factory across the road was made in cylinders, something like our artist's charcoal but bigger containers, with a big fire around the outside to provide the heat. The wood is named Cylinders Wood after that process. An original cylinder, although imported from Gatebeck, near Kendal, con be seen in the Langdale Estate timeshare opposite Cylinders Wood.