Making Charcoal and Biochar

Ben Law
Friday, 16th May 2014

Woodsman Ben Law explains how he turns part of his coppiced chestnut into charcoal, biochar for the veg patch and artists charcoal.

Walking along the woodland rides with waves of bluebells each side of me, the wet and stormy winter is disappearing into the background.

Longer days and thoughts of summer barbeques means the charcoal burning season has arrived for me. I did two burns last week, one of which formed part of a training course for those wishing to pursue this ancient craft. The other was the first burn for my apprentices and was also enjoyed by a couple of friends from the village who dropped by the woods to see the midnight antics us charcoal burners get up to.

It was a warm night and as I waited to shut down the lid and bring the burn under control, we were serenaded by the beautiful sounds of nightingales. It is moments like these that remind me how lucky I am to have chosen the path of being a woodsman.

I burn charcoal in ring kilns. The ring kiln follows the principals of a traditional earthburn but removes the need for constant supervision as the fire cannot break out through a steel kiln as it can through mud and turf. There is a more efficient charcoal kiln, the ‘retort’, of which mobile versions are available. The difficulty for a woodsman is justifying the high cost of the mobile retort against the cheaper ring kiln. If like me charcoal is just one of many products, then the ring kiln is likely to be the economic choice. If you are planning a charcoal based enterprise then the mobile retort could be the best choice.

Although most of my charcoal goes for the barbeque market, I also make artists charcoal and biochar (small grade charcoal unsuitable for barbeques which is then crushed to a powder). 

For artists' charcoal, I peel sticks of chestnut, oak, spindle or willow and pack them into a biscuit tin with lots of sawdust, which I then place near the top of the ring kiln. I have had a lot of positive feedback from artists who enjoy the different texture and shades they get from the different woods, as it is difficult for them to find alternatives to willow charcoal. 

Currently most of the biochar I have processed is going on my own garden. I don’t like to sell a product unless I can give first hand experience of using it and its results.

This takes time. So far the results are encouraging and the garden is flourishing. Charcoal is inert, so it does not add nutrients to the garden, but its make up helps root penetration and moisture retention and, when combined with manure as in my vegetable garden, the results seem very positive. 

It’s been a good start to spring for butterflies in the woods. Brimstones and peacocks have been abundant and orange tips have started to appear, I am looking out for pearl bordered fritillaries as their survival in West Sussex woodlands is very localized and I hope that Prickly Nut Wood may be able to help.

Further resources

Want to make your own charcoal? Check out our Kadai charcoal makers on our Green Shopping site

Check our our Green Shopping site for books by Ben Law:

Biochar: how to build soil, lock up carbon and build fertility


azisurrehman |
Fri, 09/02/2018 - 10:33