Biochar and the Kannibal Kooker

By Channelfog

As Carbon based beings, Carbon is crucial to us, as Humans have known for thousands of years. From Egypt to the Amazon we dig up ancient horticultural biochar that provides a viable matrix for a whole host of beneficial bacteria and critical mycorrhiza to this day. This biochar has also sequestered Carbon in the Earth for centuries, a very different topic of discussion.

Modern agricultural tradition of the last few centuries has often been to simply burn all brush or unwanted agricultural material until all that is left is ash. Rarely is this alkaline ash residue utilized in any way and 100% of the Carbon contained is released to the atmosphere while alkalizing what may already be an alkaline soil. This is where pyrolytic combustion of brush to produce valuable biochar becomes reborn in the ken of man.

We started with a cut open 55gal drum on its side which proved to be a good low Oxygen burn to make biochar. It takes an hour of feeding brush into the chamber to produce 15 gallons of biochar. It is hot work!….and the waste heat is considerable. I thought,”What if I could use that waste heat while channeling it away from my face and body?”

And so the “Biochar Kannibal Kooker” was born. The experiment involved digging a trench for the pyrolytic combustion chamber (horizontal burn barrel) and setting an enameled tub in the ground above with an earthen flue and barrel chimney. The same effort and results are achieved with the new set up with two salient differences. It is much less hot work and When I am finished and tired, I can slip into a tub of hot chlorine free water, a sublime relaxation after an hours work feeding the fire.

To get into a tub with fire still lit below is to ask for burns or worse. Also, for biochar not to be turned in to useless ash, the fire must be completely quenched with water, at which point the hot tub becomes safe for use. 

We grow the wood that we burn which makes this Carbon neutral by definition. We also plant more trees than we cut (reforestation).

While this method converts a large percentage of fuel into biochar, it still releases CO2 which alarms me not. I am alarmed by many pollutants and greenhouse gasses, but CO2 is not one of them. CO2 levels are 15% higher in less than a century and too, the green mass of the planet is up by about 15% as a result. At higher CO2 concentrations, plants need to open their pores less to consume CO2 and so they lose much less moisture to the air allowing them to spread into more arid rergions. In contrast to predicted desertification, we are seeing plants become more drought tolerant and capable of moving into previously barren areas. This net greening also applies to food crops which are more productive provided with more CO2, requiring less fertilizer from the ground.

As with all combustion, all brush/fuel must be dry or there will be more smoke created than heat. It is this factor, where people burn damp wood and trash, that creates the noxious smoke that neighbors complain about, and justifiably so. The Kanibal Kooker does smoke sometimes, but the nearest neighbor is over two football fields away, and the same distance to the next neighbor. No one is annoyed.

Fear is increasingly being used to control us and so we have only to rely on ourselves each other and Permaculture Practices to be truly Free. Learn from the ancients though their lessons are often buried….

Details: Barrel must be sealed except for small drain holes which are covered with sand during firing to prevent air flow. Wings help limit air flow and facilitate loading with brush.