My new toy

As the owner of a bush block, I do a lot of burning off. When summer comes, bushfire is an ever-present worry, so keeping the bush free of fire fuel is a priority. A lot of pruning and raking of litter gets done on a regular basis throughout the year. I’ve always felt guilty about all that CO2 going back into the atmosphere when it should be sequestered in the soil and stored there.

Enter biochar. Some of you might have read about its value as a soil amendment and a means of keeping carbon in the soil. Here’s the Wikipedia entry on it. Making my own seemed like it wasn’t going to be easy, because of the need to burn material without oxygen to produce pure carbon and not CO2. So I gave the idea a miss.

Then I discovered you can actually buy a kiln in which to burn the material.

I checked out the video at the site. It looked easy, so I took the plunge and ordered one. (Note: I wrote this draft a couple of weeks ago and couldn’t do any burning off to try the kiln, because it wouldn’t stop raining! When the weather finally dried up, I went back to the site to check out the video again and got a message saying it was unavailable. I’ve emailed the company to ask why, but if you can’t see it, there are plenty of still photos)

It came in a flat(ish) pack of four bent sections of heavy steel with a bag of nuts and bolts. It weighed a ton! I couldn’t lift the package! But all was OK; I opened it and put the panels one at a time into the wheelbarrow. It was obvious it was going to have to be put together at the final burning-off site.

I managed to do it without having to ask a neighbour for help (it’s awkward to deal with because it’s a cone, but I propped it against a tree).

Finally, I got to try it out.

Here’s the fire just about died down. I only managed to half fill it :

I added the water. A lot of steam….. :

…..and kept adding till the steam and the sizzling noise stopped :

It really is charcoal! It crumbles :

I’ll be using this as a soil additive in all the wicking boxes and tubs and the raised beds I’ve bought for more veggies.

Quite happy with my new toy!

4 Responses to “My new toy”

  1. kayepea Says:

    Bev, my computer says the site link you’ve given above “uses an unsupported protocol” (whatever that means!) and therefore won’t let me view the site – so given that I’ve not looked at the detail provided there – I have a question from your pictures please….. Why couldn’t you (or me) just hose the fire out on the ground instead of paying for that metal cone, and getting the same result? What am I missing here?


    • foodnstuff Says:

      Not sure what the ‘unsupported protocol’ bit means. I haven’t had a reply from the seller yet as to why the video is no longer available. The cone shape means the burning material is confined as it collects on the bottom, and burns without oxygen, which wouldn’t happen with an open pile on the ground (there’s no bottom in the kiln it just sits on the ground, but O2 is excluded by the ground). When you stop adding material to the kiln, the flames die down and that’s when the water is added to cool down the bottom layers and stop the burning. A pile on the ground wouldn’t die down until the material had largely been converted to ash, which is useful for minerals, but lacking carbon and with a high pH which isn’t suitable for some plants. I think the essential things are: 1) burning without or with limited oxygen, so that charcoal (pure carbon) is the desired end product. 2) cooling the product down with water so it doesn’t continue to burn to ash. 3) containment in a vessel rather than an open pile. People have used a bottomless 44 gallon drum with success (but they eventually rust out), but I didn’t have one and this looked so easy (which it was). I sieved the charcoal through 1 inch wire and added a layer to the wicking boxes and the large planter box.


  2. Chris@gullygrove Says:

    Looks different to the methods I’ve seen employed before, like an old metal drum. Although you’d want to make sure the drum didn’t come in contact with chemicals that could pollute the biochar. The cone shape of your new toy, however, would increase the burn radius greater than a narrow drum, I reckon.

    They obviously put a lot of thought into the design, and like that it’s stainless steel. Looks like a good, solid product, and you’re already putting it to good use. That looks like some lovely biochar, ready for the garden!

    Thanks for sharing.

    PS: the video link came up for me, and worked perfectly. I’m using Google Chrome as a browser. 🙂


    • foodnstuff Says:

      Hi Chris, yes the video link is working again for me, too…. I don’t know what happened there and I haven’t received a reply from the sellers yet. Maybe just a YouTube glitch and nothing to do with them.

      I’ve realised that it works better if the materials are all short lengths, so there’s nothing hanging over the edge which has to be constantly tipped back into the cone. It means being more particular about pruning and more actual cutting when I’m doing it, but that’s not a problem..,,,it will just take more time. I’m really pleased with it and the quality of the product. Apart from previously using some of the wood ash on the veggie garden, I used to throw shovelfuls of it back into the bush to return the minerals to the soil. Now I can do that with excess biochar and it’s amazing how much less a barrowful of it weighs compared to a barrowful of ash (and no powdery dust to get in my lungs!)


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