This week we attempted to make charcoal at the Falls of Clyde.
We have two small kilns and one handmade retort kiln made by Steve, (this one is apparently design 7). When we arrived up early on Thursday morning all we had to do was light the kilns as they had already been packed by Tuesday volunteers. For the two kilns they have fires set at the bottom of them and to light them you have a small metal tube to go down to reach it. Luckily we had a handy weed burner that reached right down and started the fires, and was also very good fun to play with. The mark 7 retort kiln is made from an old oil barrel on its side with metal piping all the way down to the bottom and then turns 90 degrees and the chimney goes out the top. The retort kiln differs in that the fire is contained within the metal pipe so none of the wood you are turning into charcoal inside the barrel gets burned in the process. Theoretically this should make it far more efficient than the others.
Once lit the kilns then have to get up to temperature with the lids open (apart from the retort kiln). This makes a huge amount of smoke billow out of them in the same way you would imagine smoke to rise out of a witch’s cauldron in a movie. The retort kiln had a small fire lit inside the pipe which was dutifully fed, kindling size pieces of wood by yours truly. Chopping wood that small with an axe is no mean feat. Once the kilns are hot enough, according to our instructions you should just know by experience, very helpful on your first attempt, we had to block out all the air. We tested it by splashing a little water on the lid of the kiln, if it bounced back it was hot enough.
To do this we covered the edge of the lids in soil and added the chimneys to the kilns. Any gaps leaking smoke where covered in soil. All the kilns then slowly burned off wood vapour pushing all the water out of the wood. This took different amounts of time for each kiln.
Once the smoke was blue/clear the wood vapour had all been removed and all chimneys were removed and everything was sealed up to allow it to slowly cool overnight.
The next afternoon we went back anxious to see if we had actually made any charcoal! Much to our delight and surprise we had three kilns full of great lump wood charcoal perfect for BBQ’s. We bagged it all up and it is now for sale on site. If you are interested in buying a bag come down and ask a member of the team.
Cait McCauley, Falls of Clyde Assistant Ranger Intern
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