Charcoal has been made by various methods. The traditional method in Britain used a clamp. This is essentially a pile of wooden logs (e.g. seasoned oak) leaning against a chimney (logs are placed in a circle). The chimney consists of 4 wooden stakes held up by some rope. The logs are completely covered with soil and straw allowing no air to enter. It has to be lit by introducing some burning fuel into the chimney; the logs burn very slowly (cold fire) and transform into charcoal in a period of 5 days' burning. If the soil covering gets torn (cracked) by the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air from entering.
We use a custom built retort kiln , all the materials were recycled. A retort kiln is a far more efficient means of making charcoal than either a clamp or ring kiln. There's less waste, less CO2 and more charcoal is produced.
Our Charcoal is produced from hardwood thinnings. These would otherwise be left on the ground to rot giving out CH4 , by charring it we are saving the output of greenhouse gases and that's taking into account the minimal CO2 released from the kiln.
The kiln is fuelled from waste softwoods. Those that are too small or not straight enough for the mill.
It is all processed on site and therefore no transportation is involved.