Matt R's Charcoal Retort V1

Ok so here is my very first attempt at building a charcoal retort. This first one uses a 10 Gallon and a 30 gallon metal drum with sealable lids.

Ok the retort vessel that the material you are trying to convert to charcoal must be vented. So what I did here was install a center venting tube in the ten gallon drum. This allows the gas to vent from the top and then down. The Pyrolysis gases produced once the moisture is cooked out is flamable and can be used to provide process heat. This makes this much more efficient. However the weter your gross feedstock the more smoke this thing is going to make. So if no smoke is desired you will want to run only seasoned feed stock that is dried bellow 20% MC.

On the 30 gallon barrel that contains the combustion process has two 1 inch tubes installed just bellow the bottom stiffening ring of the barrel. These tubes serve two purposes. One is to support the retort drum inside and to suppoly second stage air to the Pyrolysis gas that is produced. I drilled (5) 3/8 holes spread 1 1/2 inches appart centered in the span of the tubes.

The 30 gallon drum lid I addapted a duct flange to addapt 6 inch stove pipe for the chimney. I added 1 1/2 inch ball valve to feed the primary oxidation process. I am probbably going to add a second one to the opposing side. Then I simply fabbed up a simple door to feed the fire box with a pull latch to secure it.


Im going to my parrents this weekend to harvest a fallen tree. So that will be my fuel for further experimentation. This will probably be green but smoke is not to big an issue. I need to test trying dryer feed stock yet. It did make some pretty ugly smoke. But it was mostly pine tree branches that fell over the fall and winter I found in the yard. Just broke it all up and it was pretty wet stuff. But yeah cramed that thing the best I could. Tomorrow Im going to install it in the shop for shop heat. Yeah no reason you could not put a water coil in there to heat water or even on the outside of the outer drum.


@ Chris is there a way we can add a dedicated catagory for " Charcoal Retorts " or “Charcoal Making and process” ?


I think that will work fine. You may need to let more air in for combustion at the bottom. And more room for the fire to get out started unless you are using like used motor oil.

Usually, they run the gas pipe down the side and the exhaust gasses/heat up the middle, because the distance from the heat to the wood is shorter. And it may take less time… but you have smaller distances.


I am planning on adding a second 1 1/2 air valve on the otherside. I dont think it needs much more air. There is a second stage with ten 3/8 holes in those tubes you see that hold the retort. Those point down toward the center and they worked as planned. The center down tube also worked I saw it was flared off inside there. It worked the first time I have a half bin with charcoal twigs now.

Yeah I looked at others they dont make sense to me. They exhaust the heat too fast.

The burn box is pretty big its 8 inches tall and the drum is 19 inches diameter. Thats comparable to most wood stoves. I only loaded it once and what I loaded was fully converted. Dropped out like pouring a bag of glass out.

I installed it in the shop tonight and will try dryer and larger chunkes fuel tomorrow. I got 2 hours on one load running it at full bore. Id like to slow it down so it makes one batch a day while it heats the shop.


Plus now that its in the shop it will have the shop chimney to draft it. That is a 10 inch water pipe thats been reperposed and is about the hieght of roof peak of the shop. I bet its like 20 - 25 feet tall.


They don’t make sense to me either as far as efficiency, but there is plenty of excess energy. And I kind of wonder if it is just easier to replace the inner tube then the whole barrel have also seen them with outer jackets as well. Or if it is because the larger draft, burns the tars better.

You can also condense the heavier volatiles out for wood vinegar, etc. if you cool the gas. before burning it.

Be careful with that… If you aren’t condensing out the crap, it is going to get sucked up the chimney if it doesn’t burn. It is a lot of tars like creosote. It will probably condense in the pipe and run back down and stick, but a lot of it is still flammable with enough heat, it might catch fire.


Slow down man it was only a test run; running what I could find on the property. It was wet and I know how to run a stove. Been heating with wood for 20 years.

When the chimney drafts this its giong to lean out the mixture and Ill be running dryer fuel. That stuff I first tried was drenched. it was like 50% or greater moisture contect I mean we just melted 3 foot of snow back there in the last two or three weeks. lol

I was just testing it to see if was safe to put in the shop.


I should try this with the half-ass-Hookway I made. Cut the pipe in the center to stop before the lid and patch the lid up.

Could use one of the oil tanks I’ve gutted as the burn chamber


Yeah it designed itself. The center vent tube was the main premise, but when I got to the part where holding up the inner barrel came. Im like ok what do I have in here that I can use to support this inner drum? Then I saw that tubing and Urika!! Sweet!! I can punch holes in the outer drum insert those pipes and then add holes for a second stage air. Nothing here was really planned only the concept of that center vent tube. lol


Here is the temperary install. I have a couple elbows on the way to get it away from batteries. Right now it perfectly fine its not running too incredibly hot.


I just remember all the black tarry crap that came out of mine, and a 20 ft pipe is like a huge reflux condenser.


Right on yeah, what Im worried about is this thing going into a run away mode. There were a couple times where I took that valve off because its not really 1 1/2 more like 1 inch. When ever I did that it would take off, turn red and start rumbling. So I would quick put it back on and throttle thing back down.

But for the most part I kept it running fairly cool running with this mild weather and it kept it comfortable in the shop. Chimney smoke was not all that bad it stayed white and Ive actual barrel stoves that smoked more than this thing.


Yeah I cant complain about this, It made charcoal all day while it heated the shop. Plus it didnt really use a whole lot of fuel. I loaded it three times today and you dont really put a lot in there.


Ok so I measured the 55 and 30 gallon drums and its a go to scale up. I think Ill build two of them thats 40 gallons bettween the two. I can then run them both and make that much fuel in one shot.

Then Ill be running my new 2024 CFX demo running both Predators in tandem this year and Ill see if just the two are viable per day. Im sure I could run two batches a day so theroretically I could produce 80 gallons in a single day. If not Ill make another one. This is way easier than processing wood.


Looking at the wood in the barrel, are they long pieces of wood you have split up using the wood splitter or a they sawed wood?


I’m a little disappointed. To fit the ammo box mantra… they do make
these :rofl: :rocket:

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Just lumber scraps and old pallet I cut up. Tomorrow Im getting a tree so yeah Ill be processing it. But all I have to do is cut and split it for this thing. No chipping or chunking then sorting and then drying and waiting and waiting. lol


Thought I had missed out :slightly_smiling_face:


I have a guy I found on Craigs List that I can get 55 gal drums with lids for 20 bucks. At least thats what I paid a year ago. Ill have to go look again.