More on how to make biochar

Step 2. Fill the barrel. I started out with a pile of sticks Val had collected in the woods, but realized that sticks take up a lot of space, so I broke them up into pieces. I hunted through our recycling bins and pulled out all the newspaper I could find. Then I remembered the pile of weed chips from our chipper up on the septic mound, and I gathered the long decorative grass we had trimmed away too. I think this was a mistake—some of this material was damp, and the need to boil off the water delayed some of the pyrolysis. This is how the pieces of sticks looked:

I filled up the barrel with stuff, shaking the chips down among the grass stalks and sticks. I laid the paper along the holes in the side, figuring they would hinder the entrance of air later.

Step 3. The fireplace. I used the BBQ pit where we had cooked a goat a couple years back. (Digression: We stopped having those BBQs while we waited for our addition to be finished, so we wouldn't have a mob of guests and a construction site together. Go to http://inferiorbuilding.blogspot.com for an update on that fiasco.)
I dug out all the old ashes, scraped the old unburned wood to the side, and arranged some fire brick to support the barrel on its side, holes down, where they would be in the fire. When the gases started to come out, they would ignite and contribute to the heating.

The technical term for fire brick is refractory brick

You can see the goat shed in the background

Step 4. The fire. You already know how to build a fire, right? (Actually, I'm planning a post that teaches how to build two types of bonfires.) We have a large number or cut-up pallets, not to mention more piles of sticks from the woods. My total fuel for the evening was two cartloads of pallet pieces and a cartload of sticks. Here's how the fire looked at the start and how it looked after I got things going. It took pretty much constant supervision, mainly because it was light wood that burned down fairly rapidly.

There's plenty of fire below and along the sides, too

Horizontal sticks weren't as good as vertical ones

This evening was the Civil Air Patrol Cadet Ball at the Dover AFB, so I lost use of the camera for the later stages, when you could see gases streaming out the holes into the fire under the barrel and along the band that held the lid in place. Eerie blue flame. It was pyrolyzing!

Total burning time was about five hours, then I let it burn out and cool down overnight. Next post: the results!