Since I learned how to make easy biochar, I've been at it hammer and tongs. I discovered that it needs at least 1 hour of burning to make sure that the content of the inner can is properly carbonised. 45 minutes is not enough -- the central part of the material is only half-charred.
Having laboured several times to fill a small can using a handsaw, I finally took myself to the DIY store and purchased a nifty little electric chainsaw. A task that took nearly two hours now only takes about 15 minutes.
I also took a metal saw to my incinerator and opened up the top so that a bigger can will fit inside. Next weekend I plan to try a double-decker can tower, or what we in the defence community call a multi-stage biochar weapon.
Now that I have the means of cutting up bamboo very quickly, I can achieve my long-cherished dream of taking out all the dead wood from a bamboo grove so that everything can grow straight and without disease. Amazing as it seems, the small oil drum in the bottom left of the picture above contains all of a single mature 'moso' bamboo culm, nearly 10 meters tall. Plus quite a lot of rice husk. Of course.