Yeah, I get that but, personally, I feel, the creation of biochar is supposed to be a clean, smoke-free process so as to make the storage of the carbon the most efficient.

I can understand the manure retort experiment (my grass burn was also an experiment but not something I did again) but it would have been nice to have seen a clean burn attempt. Since he was picking manure up off the ground right next to a cow’s arse, you can’t even guarantee low moisture fuel or feedstock.

Maybe an airgap at the base of the flue might allow a secondary burn inside there.