Wednesday, May 27, 2009

Crane Hill Bio-Char Kiln

Welcome to Crane Hill Gardens!
Some folks very interested in Bio-Char production invited me to build an earthen kiln on their land.

Making cob adobes with the soil from below the kiln site.

Very heavy clay and silty soil...
Made wonderful bricks!
Oh, the glorious 55 gallon steel drum...
what earthen burning device can do without?

Adobe perimeter walls

Cobbing in the flue pipe
Light Clay-Straw insulation
loading it up for the test-run
Finally found some pure clay at the local gravel pit. It's the last thing they want to find, so they gave it to me for free. Two colors of clay here in easily divisable layers.
Shredding and screening straw
even found some catails to test in the plaster mix
(what an adventure in material acquisition this has been!)
the finished kiln

more on the wood vinegar colleciton system and char results soon to come!


  1. Man I've only been following your blog for a short time now, but i am lovin' it.

    Is there anything you cant cob?

    Ok here is the challenge; an indoor stove with a gridle on top for cooking on, but the waste product is char, oh and the sides are cob for retaining heat.

    Ready, go!

  2. hi, thanks again for following.

    earthen bio-char kilns are where it is at! and thanks to some of my lovely students at this workshop, I am full of new ideas about how to improve the design and make it multi-functional.

    the main thing i want to do next is instead of collecting wood vinegar by condensing the volatile oils, i want to create a double chamber so that as it heats up we can pressure off those gases and actually burn them to continue heating the kiln... or we could rig it up to a cook top and use those gases to feast while we make char. so bio-char wouldn't be the waste product, it's more like the cooking takes advantage of the wastes product. we've got some similar ideas tho, totally on your wavelength.

    We could do it indoors, but would have to run the flue outdoors, and being that it would produce a lot of heat, we probably wouldn't want to use it indoors in the summer... I suppose if you were really organized, you could make all your char during the winter months and be ready for spring!

    thanks for the mental challenge. i'm always up for one!

  3. Nice work Erica! It looks beautiful, and kudos to the Crane Hill Gardens folks for making biochar. I look forward to hearing about their results. Our tiny initial tests this year look great, and we hope to get a production scale system running as part of our maple syrup evaporator this winter.

    Tree Gate Farm

  4. Modify your brick press, and press the biochar into blocks, using a little bit of water. Once dry, the biochar blocks can be burnt in your cooking oven.