A charcoal experiment

We've decided to try to make charcoal for medicinal uses. Since we've never done this before, I knew it would be an interesting experiment. We researched to find out what would be the best wood to use and ultimately chose willow. After we found the willow that was the right size, we stripped the leaves off and the boys cut it up into the proper lengths.

From what we read, we needed an airtight container to put the willow sticks in. The best thing we could come up with was one of my canners. I figured we would put the lid on and then secure it with C clamps.


So far, so good. The boys had a fire going so I tightened the C clamps - any tighter and I would've cracked the enamel. Then...onto the fire.


They cooked and cooked. THEN, I noticed that some smoke was escaping from under the lid. So it wasn't airtight after all. :( We were supposed to let it cook for 1 1/2 hours and then remove from the fire to cool entirely. If we were to take the lid off while it was still hot, the oxygen would cause the charcoal sticks to burst into flame and turn to ash. So, after determining that it was indeed leaking, we took it off the fire. When it was almost cool, the lid was removed. Curiosity was getting the best of a particular boy. ;) It didn't burst into flames-it had apparently cooled enough- and we discovered that we had made charcoal pencils! Those sticks were in the pencil sharpener in NO time. lol. So...that was our first attempt at making charcoal. It was fun and we ended up with something usable. Now, I just need to come up with something airtight that can go over the fire. Any ideas?