Biochar Cone Kiln

Here is another well made demonstration video on simple biochar production. This relates to another ‘managed combustion’ system – providing much better environmental outcomes than just burning biomass but still wasteful on the energy front.

See also:

Keeping it Pure

Last night, Prime TV aired the third episode of ‘Keeping it Pure’ which was focused on water… “Most of New Zealand’s monitored waterways are polluted, but how has this happened and is it possible to turn things around?”

I think they did a good job but in ignorance of biochar as a possible tool to solve some of these issues. I hope to make contact with some of the scientists and other folk featured in the documentary to engage with them on biochar. If you know any of these people, it would be very helpful to point them at biochar and this website.

The link I had no longer works but I’ve found the trailer which sets the scene (episode 3). If I find access to the complete documentary, I will post a comment…

TLUD Update – updated

I had an epiphany while running a comparison between a couple of TLUDS at Simon Days about 10 days ago. I’ve been trying to get more char out of my system by raising the afterburner about 50mm above the main barrel so I can feed in extra wood through the secondary air inlet after the burn stabilises.

While the secondary feedstock has been charring well, the main charge has been producing too much torrified and untouched chip. I suddenly realise that, by raising the afterburner I was destroying the draft created by it and the flue because the extra gap meant that the flue was not drawing any air through the bottom of the barrel, the secondary air inlet was the path of least resistance.

I reverted to the original configuration, with the afterburner sitting firmly on the top of the barrel and the previous good performance of the system returned with less than 15% brands.

Then, greedy for more product, I tried removing the afterburner during the burn and adding a small pile of branches up to 50mm in diameter. At first I thought I had broken the system with huge amounts of mostly white smoke billowing out and no chance that the afterburner would relight to combust the smoke. However, I realised that the fire front, about half way down the barrel, was proceeding as normal, the draw from the flue was still working at that level.

Next option was to remove the afterburner again and add some dried cryptomeria foliage, my favourite fire starter in all cases. I quickly had the smoke burning again and the temperature of the afterburner rose to a self-sustaining level and the burn proceeded as normal.

The extra wood charred very well, all the way through, with very little smell and a nice crisp snap on breaking. Final composition was fully charred with no more than 15% brands and possibly less.


  • The original design appears to confer the strongest draw through the main feedstock charge and I have abandoned the wider secondary air gap.
  • Opening the system to add an arbitrary amount of extra material for charring seems feasible
  • It will depend on reigniting the smoke with more tinder before replacing the afterburner.

Next time I will try to double the extra fuel and/or add in some road kill to add calcium char as well.

Next Time

Another run today, (February 14) adding about 10 litres of various sized branches around 30cm long and between 10mm and 30mm diameter.

Once again we had trouble reigniting the afterburner, the moderate breeze that sprang up during the burn didn’t help, blowing out several matches while the barrel smoked liked fury. once I got a bunch of cryptomeria actually burning I still had to hold the afterburner partially open for a couple of minutes to keep the flame burning really hot and bring the afterburner up to temperature to ignite the pyrolised gases.

After that it settled quickly and burned normally till the end with about 10% unburned material as usual. The results of the extra feedstock were spectacular. All of the extra wood was almost perfectly charred, snapped cleanly and had very little to no smell. All of it looked like this

30mm branch added to TLUD after the burn had established at about one third of the way through the burn.

30mm branch added to TLUD after the burn had established at about one third of the way through the burn.

Next time I will just take off the flue and add the extra wood through the top of the afterburner. We wont be able to control the distribution on the top of the chips but I’m not expecting that to make any great difference; the space is very hot and anoxic, as this material demonstrates perfectly.

2014 Biochar Companies & Organizations

I’m not sure that this link will work for you all… it is an extensive listing of biochar companies on the Biochar Farms & Gardens Linkedin group. You may need to be in the group to access.

2014 Biochar Companies & Organizations Alphabetically Listed by Thermal Conversion Technology Type, Organizations by Services

Biochar Systems Consultant Top Contributor

Please send me New Companies for Addition & Failed Companies for Deletion;”

Climate change, geoengineering, biochar – the NZ link

Biochar is a veritable Swiss army knife for some of the planets problems. There are many tools being unfolded for agriculture enhancement and environmental repair. Energy tools abound, due to the diverse range of biochar production methods, and their residual and distributed nature. Continuing the analogy, one of the largest and most controversial knifes is still to be sharpened.

Some biochar proponents are pushing hard for biochar as a carbon sequestration tool. It is suggested to be a passive and safer approach to geoengineering the planet compared with other CDR (carbon dioxide reduction) or SRM (solar radiation management) methods that have emerged from the geoengineering community.

Kelpie Wilson has posted on a two year NZ and UK study looking at public attitudes to geoengineering. Her link leads back to the Manawatu Standard 13Jan news report but she says nice things about sensible kiwis so do check out her blog…

I’ve been engaged with this issue from another perspective – the NZ ETS… my comments are included in Euan Mason’s blog post below…

Biochar producers page

We have been getting inquiries for biochar – mainly from gardeners wanting to experiment. As interest grows, demand for larger quantities should follow for commercial application trials. If you are producing biochar in NZ and you are able to share some of your production with gardeners or researchers, then please get in touch.

As the market for biochar matures, we should develop some principles and guidelines for sustainable and safe biochar production, post-treatment and application. The easiest path for now may be to follow IBI, European or other international production / testing guidelines.

We are developing a list of NZ biochar producers who may be able to provide biochar or biochar based products from direct inquires. The producers page will provide contact details and product information.

Biochar Burn School

Kelpie Wilson from has led this initiative…

“A quick summary of results of experiments in open burn techniques to minimize smoke and maximize charcoal production. Experiments were conducted by volunteers over a 3 day period, November 15-17, 2013, outside of Grants Pass, Oregon.”

Biochar burn school 1Biochar burn school 2