Well, searching for info on terra preta is what led me to this site to begin with, so I think it is only fair for me to share what I had learned about biochar kilns prior to arriving. This
site is a link to a kiln designed by a guy that uses charcoal for blacksmithing. I think it is unique though, in respect that it is easily customizable, and relatively impermanent. Meaning, you can set the kiln up when needed, and disassemble for storage when not needed. It uses 55 gallon metal barrels for the retort and concrete blocks for the kiln body. I would be interested to know if anyone had used a kiln similar to this to produce biochar at the temperatures that preserve wood alcohol levels, in other words low temperature biochar production rather than high temp production. This seems to be the most important factor (along with char component size, which can be adjusted by crushing) involved with biological usefulness of biochar, but I have no experience with using biochar. Any input would be greatly appreciated.
