I found myself making charcoal last week. It’s a bit strange but I do sell a small amount of charcoal around Christmas and the New Year. Perhaps its global warming?
This year I didn’t have enough left over so I needed to make a few bags more. I make my charcoal in old 40 gallon oil drums using birch cleared from the commons as a part of the heathland management. So it’s local and quite environmentally friendly in comparison to the vast quantities that are shipped into the UK each year (it also burns hotter, faster and is cleaner without being impregnated with chemicals) .
To make a few bags I only needed to burn a couple of bins but despite my best attempts to start earlier in the day I ended up doing the whole burn in the dark.
There was something quite satisfying about burning so close to the winter solstice. The tawny owl that lives in the woods came to keep me company.
In the dark I could not fill in the time with other jobs and unaccustomed to doing nothing during a burn I ended up trying to take photos of the bins.
I make charcoal in old 40 gallon oil drums. I choose to do this for a couple of reasons It doesn’t require any investment (buying a purpose built kiln can be expensive) and I can make the charcoal at the end of my working day, the burn taking only a
couple of hours.
It is quite easy to do demonstrations for visitors and encourage others to do the same with waste wood. Unlike a big (8 foot) kiln which takes over a day to burn you can seal the oil drum after a couple of hours and then safely leave it to cool and come back the next morning to unload the bins.
While the bin is lit the aim is to burn off all of the moisture and volatile chemicals until you are left with pure carbon which is then sealed up to cook in an oxygen free environment using the retained heat of the fire.
If you don’t seal the bin in time you will just be left with ash as the wood burns away entirely, and if you stop too early not all of the wood will be carbonised completely and large ‘brown end’ will be left.
During the latter stages of the burn as the vents on the bin are slowly shut down volatile chemicals can be trapped and if the lid is lifted without care they can literally explode out of the bin (don’t try this at home!).
Being bored I kept looking to see how the burn was progressing and tried to capture this effect on camera whilst waiting for the burn to finish.
Several attempts to take a photo as I lifted the lid failed. Partly due to the ferocity of the flame and partly due to slightly singing my hand having taken my gloves off to work the camera. But you can see from the shape of the flame in this final photo taken after the initial explosion of flame from the bin that it’s actually the volatile gases burning outside the bin.