Making charcoal.

[Dave Shepard]

Anyone make their own charcoal? I'm thinking about building a retort to cook some hardwood scraps from the firewood processor. I have a lot of dry pine slabs to get rid of, and I think it would be cool to make use of them for something useful. 

[Don P]

I checked the 500 gallon old oil tank today from burning a whack of scrap in it Saturday. I cut the end out, lay it on its side and load it with edgings and scrap, big slabs don't do well. Then stand it up, intakes down low. I light the top and let it burn down then drop the lid on top and scoop dirt onto that... really bad drop this time it didn't land flat. Then I pile and pack dirt around the base to seal all openings and let it cool down. That is the crude direct fired method rather than a retort, I'd like to see what you come up with. I'll tip it out and screen the fines and ash out, if the dirt contaminated it all I'll call it biochar, mix them well and give it to the wife for the garden.

[mike_belben]

I did it once.  Had a bunch of carpenter ants in some red oak so i lit it and got the pile ripping then buried in dirt via bobcat.  Dug it up later.  

It worked okay but wasnt anything too special to me. I cook on dry split wood fairly often. 

[doc henderson]

I do it 2 or 3 times a year.  I like to cook over a wood fire, but also lump charcoal.  I will see if I can find pics.  I have video but have never got a you tube account set up.  I use 30 gallon oil drums with the crimp on lids.  I drill a dozen 1/8th inch holes in the bung in the middle.  place that full of hardwood in the fire ring, and burn what ever on the outside.  then watch the smoke go from white (steam) to gray (volatile gasses)  and then flame, then nothing and you are done.  let it sit a few hours and cool then open.



 

 

 

 

[doc henderson]

I noticed in the pics that two people look like they are on fire,  that rarely happens    :D.  but shows the flame you get in the volatile gas phase....  yes the gas from the wood in the retort.  ;)  so that all that is left is 99% or so carbon.

[peakbagger]

FYI, a lot of the gas being burnt off is Carbon Monoxide, odorless and colorless. Be careful its easy to get a dose. 

[Joe Hillmann]

I make small batches quite often.  When I burn small scraps I wait until it is mostly coals then cover the fire and choke it out. 

I have a 2 wheeled tractor that has a charcoal gasafier on it.  The bigger stuff gets saved for that.  The smaller stuff gets ground and goes into the compost pile.  Charcoal is supposed to be great at holding nutrients and water in the soil.

[doc henderson]

yes this is an outside project.  the gasses are all kinds of the sap and resins in the gas phase.  I do not claim to know the chemistry or all the components of wood, but the gasses are prob. a range of methane to propane and all the other "anes".  the solid carbon remains, and do not burn without oxygen.  the boiled off components that leave as a gas, can burn when hot, exposed to flame and oxygen outside the barrel.  If you think about a carbon filter, the carbon can interact and bind to lots of other elements.  That is why it is at the core of life as we know it.  the majority of the gasses are carbon dioxide and water vapor.  carbon monoxide itself is actually flammable as it is partially or incompletely burned fuel.  carbon dioxide (CO2) is not flammable and is therefore also considered an inert gas, used in welding.  a room full of carbon dioxide will smother a fire or a human as well for that matter.  carbon monoxide (CO) binds to hemoglobin 50 time stronger (like a magnet) than oxygen so you can smother with small amounts of CO.  Non smokers have a CO level of 0 to 5%, smokers have a CO level of 5 to 10% normally.  a level of 50% in blood is considered lethal.  newer boilers and furnaces are so efficient, that a chimney leak is less likely to make anyone sick and less likely to cause poisoning and death.  the antidote for CO poisoning is O2 in high concentration to displace the CO from the Hg.  Atmospheric O2 is about 21%, and we can give 100% O2 and effectively higher with pressure (hyperbaric chamber).

[Paul_H]

This was from a few years ago but a excellent way to make charcoal. I make it for my charcoal tractor

Reply #15

https://forestryforum.com/board/index.php?topic=81327.msg1239729#msg1239729 

[scsmith42]

I've made my own for years.  My  method is a little bit different than Doc's (but I'm going to have to try his out because it may yield better results).

In my instance, I took a 55 gallon steel drum with  a removable lid and drilled 5 holes in the bottom of it. The holes are around 2" and were drilled with a standard hole saw.



 

The drum sits on three pieces of brick that space it up a couple of inches above the ground.   In-between the brick foundation it's filled in with sand around perimeter of the drum, but with a 6" or so gap in one spot to allow air to get under the drum and up into the holes.



 





 


Once the drum is filled I'll get it started, and allow it to burn down for 30 min or so.  Then I put the lid in place, but with several inches overhanging to allow it to continue to burn.  The smoke starts off as a dark color; when it turns light gray I'll put the lid on the rest of the way, weight it closed, and block off the opening in the sand at the bottom of the drum. 



 

Voila, home made charcoal!



 

[Don P]

Paul, Scott and I are doing the same thing, direct firing the wood where Doc is indirectly "cooking" the wood in an enclosed container with the heat outside of the container. The yield is higher since he isn't consuming part of the wood to make the charcoal although the total amount of wood used is probably similar. Doc's charcoal is cleaner with less ash in with the charcoal than with direct fired. Paul's afterburner helps clean up the smoke. If I did more of this I'd get another tank and use the knuckleboom to lower it in place when it is lit, I've seen a lot of that yellowish green unburned methane cloud departing early in the burn that would ignite in the afterburner.

This is a pic of the old oil tank, just a bigger barrel;


 

[Al_Smith]

I don't really make but I do on rare occasion dig down in my slash burn site and dig it out of the ashes .It's only a couple times a year, if I'm in the mood to fire up my charcoal grill and let it burn down to coals .Takes a couple of hours burning down hickory before it's ready .I think I might have a 5 gallon bucket with a lid on full of lump charcoal and another full of briquetes .
My fire ring  in the center of my back patio is a rear rim from a 1940 John Deere A with two layers of concrete fancy bricks around and a fire brick floor .It gets so much air all that comes out is powdered  ash, no charcoal .Good for roasting hot dogs but not for much else .You could  build up the coal bed but it would take a half a day and a lot of beer and a lot wood .

[doc henderson]

the indirect fire method produces a very "clean" char and you can let it go forever, and bet nearly pure carbon.  est. 99% from what I have read.  without O2, the carbon sits in the retort.  when you no longer have flames out the top or side of the lid, you are done.  you can add sticks and get artist style charcoal.  a 30 gallon barrel will be a little over half full, when done and I have #12 paper bags I put it in and that is just the right size to go into my chimney starter for charcoal.  lump charcoal burns hotter and shorter than "kingsford".  perfect for a steak hotdog or burger.  not as good for Dutch oven hour long cooks.  we have done that with coals from a camp fire.  In scouts, I was always being asked to make sure we hade charcoal, and propane to start the charcoal over a burner.  I finally said we need to use natural materials, or we might as well stay home and cook in the kitchen.  if you use fire coals with a cast iron cooker, use less as it burns hotter.

[Machinebuilder]

 lump charcoal burns hotter and shorter than "kingsford".  perfect for a steak hotdog or burger.  not as good for Dutch oven hour long cooks. 

Its been a long time since I have burned any brickets.
Close to 20 years ago I bought a Big Green Egg smoker/grill. since then I have tried many different lump charcoals.

I have found that the species of wood use to make the charcoal significantly changes how hot and long it burns.

I currently only have 2 different ones, one is Kamodo Joes Big Block lump charcoal. It burns fast and hot, very similar to Royal Oak lump charcoal.
The other is a Gordon Food Service Mesquite Lump Charcoal. it is extremely dense and slow burning. I use it for smoking a pork shoulder or brisket.

After reading this thread I'm ready to take a 55Gdrum and try making my own again.
I tried a few years ago and failed pretty badly.

[doc henderson]

Hedge makes dense charcoal, soft maple not as dense.  oak in the middle.  the briquets have binders and even ash to slow the burn so it lasts longer.  lump light faster as well.  just a learning curve.

[Dave Shepard]

So what is the difference between species? I'm guessing just density, as they all should have the same energy by weight.

[mike_belben]

 flavor.


I dont care what you cook over hickory, youre gonna taste it.  From butts to beans to stews to syrup. 

[doc henderson]

yes, a wood that is very heavy even after dry, should yield more char by weight and BTUs.  more carbon.

[Machinebuilder]

I guess the big difference is density.

I don't use charcoal by weight, I put what I think I need in the grill and go from there.

SO If I look at it by weight I am probably using similar amounts for the same length of time.

the other difference in charcoals is the size of the chunks, I've had some look like a piece of firewood and others like dust.

IMHO the ones to avoid are made out of flooring factory scraps, they burned hot and quick.

For flavor charcoal doesn't give that much, I add chunks of wood for that.

Mike, You're in TN know everything is smoked over hickory :D :D :D

I prefer cherry for poultry.

[mike_belben]

Its pretty sad.. since hickory is a very prevalent tree for the state.. That the handle mills have gone which was the best money you could get for hickory.. $800/mbf last load i sold maybe 2018.  

There are charcoal plants nearby but they only buy chipped semi loads far as i know.  

Up north its a desired firewood.  In tennesse hickory is often shunned as a firewood for a reputation of melting stoves and burning too hot.  

So i just set it aside for the smoker or leave it grow most of the time.  Makes a lot of mast and shade.

[Tacotodd]

Also makes for A good part of a Charlie Daniels song. Devil went down to GA. What's the Devil doing to our Hickory stumps 🤬

[Don P]

Charcoal, in and of itself really has no flavor, it is just the carbon. "Brands", incompletely charcoaled wood has flavor, or adding wood in some form or another to the coals adds the wood smoke flavor. One forester here puts on demonstrations usually a couple of times a year demonstrating making charcoal out of ailanthus,"tree of heaven... stink tree". Once it is charcoaled it is just another lump charcoal with no off flavor, and it uses a non native nuisance.

I know the binder in some briquettes is clay.

I've set up a double screen before with chicken wire on top, what rolls off of it has the brands picked out and thrown back in the barrel and the rest is larger sized grilling lump. the screen under that is around 3/8" diamond mesh. What rolls off of it is foundry charcoal for aluminum melting. What falls out the bottom is ash and biochar for the garden.

A friend made a 55 gallon drum barrel retort. It layed on its side supported by rebar on blocks with a block surround for the fire pit. Out of the 2" bung which was on the bottom he elbowed it back around and under the barrel and drilled holes so the flaring gasses would help heat the barrel. Worked great till creosote plugged the holes and the expanding gasses had no way out of the barrel. The lid went an impressive distance!

[mike_belben]

Kerry corporation seems to have done quite well for itself extracting the flavor alone as "liquid smoke" then selling the post pyrolysis char waste product to briquette manufacturers. 

[Al_Smith]

Now a story .Henry Ford of model A fame didn't waste anything .Some parts of the model T and A were made of hardwood cut from Michigan forests that of course Henry owned .Oh my what to do with the mountains of saw dusts ? So whoever did it they figured out how to made briquettes and thus was born Kingsford . Henry gave it to his brother in law if I have the story correct . 

[Don P]

If I remember the story right he ordered parts shipped on specifically designed pallets that became things like the battery box, dash, and floorboards. The unused wood was also part of the feedstock for the charcoal plant.

[Mooseherder]

We swung by Henry Fords mill with Jeff on the atv trip to the U.P.  I don't remember if this was for making charcoal.



 

[mike_belben]

Briliant.

[Don P]

Made me curious for more details;
Kingsford (charcoal) - Wikipedia

[Al_Smith]

If you ever get a chance make a stop at the Henry Ford museum in Dearborn Mich. Plan to spend the day because it takes that long .How could any one person ever accumulate that much wealth ? While you are there look  because my name is on at least  four  engines that were the last ever produced .One is a Ford 460 V8 .

[Ron Scott]

Built Ford tough in General Board (forestryforum.com)

[Beau Woodworks]

Anyone make their own charcoal? I'm thinking about building a retort to cook some hardwood scraps from the firewood processor. I have a lot of dry pine slabs to get rid of, and I think it would be cool to make use of them for something useful.

Yes, we make charcoal as a sideline. Made up a small batch retort which has proved excellent. Retorts are so efficient you may find you do not need much of your pine to convert the hardwoods into charcoal. 

[Don P]

You know that's gonna take a picture  ;D

[Beau Woodworks]

You know that's gonna take a picture  ;D

Did try but yet to work on how to download a picture onto here. Maybe too new to be allowed? 

[Don P]

Here's a link to a video tutorial on posting photos here;
Updated Photo Posting Tutorial in Technical Support Topics (forestryforum.com)

It takes a few minutes the first time but it is second nature now. The plus side is the forum has just about every photo going back to the beginning. It has proven to be well worth the effort. When you look back to an old topic about making or fixing something, all the pictures are still there. That is so rare and so often frustrating when I think I've found info while searching the web, the text is there and the pics are gone.

If you're doing it as a sideline, I'd like to see the support setup for the operation if you don't mind... just how are you handling, sifting sorting, and bagging the mess.

[Beau Woodworks]

 

 

 Thanks for the link. 

One of the retort and one of my very simple grading set up. I have lots more pictures but they are still on another computer that won't speak to the internet without crashing haha

[Don P]

All I've done so far is sifting through screens. I've seen tilted screen cylinders for cleaning root crops that would make quick work of that. It could continue to a section with very coarse screen so the really big stuff goes out the end to be crushed or reburned.

Is the retort an indirect fire under a sealed but vented box of wood sitting on top of the firebox or is everything ablaze in a single container and then snuffed, or ??? ? I guess describe a setup and burn. What I've done so far is better than a bonfire but caveman crude.

[Beau Woodworks]

All I've done so far is sifting through screens. I've seen tilted screen cylinders for cleaning root crops that would make quick work of that. It could continue to a section with very coarse screen so the really big stuff goes out the end to be crushed or reburned.

Is the retort an indirect fire under a sealed but vented box of wood sitting on top of the firebox or is everything ablaze in a single container and then snuffed, or ??? ? I guess describe a setup and burn. What I've done so far is better than a bonfire but caveman crude.

It's a retort so the fire and the charge are separated. I have a barrel set up on a frame inside there. I use waste wood to burn under the frame and the barrel gets slowly cooked. It has a unique way of diverting the gases from the charcoal into the fire which I can't divulge at this stage . I run the firebox at 450c-500C that's 843F-932F I think. 
I load one large garden trug of dry waste wood into the firebox. Load in the barrel and the gas system and close it up. It now has an automated air control unlike in the picture so you light it and walk away. It takes 4 -5 hours to convert the wood. When done you take out the barrel and reload with about half a trug of fuel and another barrel of wood. For the charcoal, I use smaller diameter wood that is less desirable with our log customers and would have been wasted before and get 100% conversion rate. Got a great little machine for chopping it all up like this https://www.youtube.com/watch?v=jVK0OMGILyE&t=32s&ab_channel=REMETCNCTECHNOLOGY
The grader is basic but works well as it's good not to over agitate the charcoal as this will break it up more. I just shake the charcoal down into a builders bucket with a line drawn on it at the right amount. Then pour the measured bucket into the bags. I only do it as a hobby so the extra time spend screening the charcoal by hand doesn't really matter to me and it's cheap!
Hope that all makes sense

[mike_belben]

Nice.  What happens with the fines?

[Don P]

Mike, do some googling on biochar and soil building.  Terra preta (spelling?) is the amazonian soil type they are usually talking about/trying to create but it is common to have high charcoal content in soils in places worldwide, the black earth of the prairies is generations of grass fired charcoal. From the little bit I've played with I have noticed charcoal fines are light and mobile, heading for the creek. If that becomes common practice we need a better understanding of downstream effects of that. If nothing else it does help soil tilth.

[Beau Woodworks]

Nice.  What happens with the fines?

We live on a farm so just chuck them in with the compost. I have experimented with it on the veg beds but cant honestly say I noticed the difference but it wasn't very scientifically done and wasn't 'charged' first. Some charcoal makers successfully sell it as biochar. I do have one lad who takes a bit to use in his forge.

A bit of info on Biochar here UK Biochar Research Centre | Welcome to the UKBRC

[mike_belben]

Thats where i was going with that.  I have researched it and played around with it in 2017/18 and basically decided it was bunk.  A bunch of people needing money with something from nothing to sell so they make up a wizzbang fertility story and pray to the climate gods.  


In terms of adding nutrient to the soil i still call BS... however i have changed my stance on being useless.  The charred pieces have tremendous surface area in the cracks and seams yet hold together like the aggregates in really really good living soil. This creates lots of porosity for oxygen holding and water infiltration. It creates spaces for critical arthropods like ants and centipedes.. And most importantly, spaces for micorhizal fungi.  


That is its best feature and it would show results much much faster if the char was first innoculated in fungi.  Leave the char fines in a pile in shady wet woods covered in forest litter, punky decayed wood with white fuzz etc.  Hose it down with some type of sugar water to jump start the percolating and feeding of the fungi down into the char bits.


Adding it below grade to ones best garden bed could be going backwards for a while, because that is disturbing old fungi to install young fungi.  In that case id scratch up the top, spread some char then mulch over that thick to keep sun from drying it.  Fungi must stay moist.  

Really dead crusty dusty clodding hard crop tillage dirt has no fungi to left to disturb so in that application id turn it in.  You can only make dead dirt better.  

Next year i intend to compare char to stump grindings which is my present favorite material.  I have a supply of "ramial" only branch chips being delivered now too for comparison. 

[jake pogg]

I make charcoal on a fairly regular basis,for forging fuel.

I think my method would fall under Don's definition of "caveman" kind,a reclosable 55-gal drum that gets loaded with wood split to under 2"/about 1' long(very much like cookstove wood),fired with restricted exhaust,and eventually snuffed with a lid.

I've gotten used to referring to this as an"open-retort" method but may well be technically incorrect.

I try to implement elements of the Japanese method(-s),though have never bothered to try to copy their style of a rig.

A part of the Japanese idea is to try to leave about 15-20% volitiles in the resulting charcoal,as they do contribute a slight amount of BtU's,and are also said to modify the burn in other ways.

The only species available to me is White spruce so the resulting charcoal is on a softer side,and of course is nowhere as rich in calories as most hardwoods.

However,the softwood charcoal gives off it's calories at much faster rate,which makes it better for forge-welding vs a longer burn desirable for more of an extended forging operations.

One of the most important factors in welding is to create and maintain a reducing atmosphere zone in your fire-pot,and that's where the remnant volitiles come in handy,combining with less oxygen and faster they "temper" the fire(making it dirtier and richer in C).

Wood pyrolysis is a surprisingly complex,difficult to control process(even with most sophisticated equipment).
Some rules of thumb that i follow,or try to,the factors to shoot for are:

Resulting charcoal must fracture cleanly across the grain,as a sign of it being "done".
It is desirable for the fracture to be glossy,a sign of it not being over-done.
And lastly a truly caveman factor that of a lump of charcoal not marking your skin when drawn across the back of your hand(which i think is a simple density indicator),also as a sign that the product has not been over-cooked.

Whenever i travel to town(i live remotely and hundreds of miles from the nearest road),i enviously examine friend's stashes of beautiful,store-bought hardwood charcoal,oak,mesquite,fruitwoods,et c.,that they use for outdoor grilling.

However,this poor soft stuff that i come up with is surprisingly efficient:A forging of a couple+ pounds comes to heat very rapidly,making it eminently practical to work up and axe-head size tool of any complexity of construction;the nature of this fuel in no way a limiting factor in the process.

I use a hand-crank blower for air-blast,and a very modest firepot.Originally owned by an Amish family in Kansas(they upgraded:)),it was cast sometime in the 1860-ies for use with bituminous coal.Again,surprisingly,it works just fine with this softwood charcoal,though in welding it needs filling every heat.

As to the question of why any particular species would produce it's own flavor in cooking,possibly it may have to do with that % of remnant volitile compounds...But i really wouldn't know the science behind that. 

[Machinebuilder]

I gave the charcoal making another try on Saturday.

I use an old drum that was laying around, filled it with variuos pieces of scrap and the top didn't fit well because the drum was a bit out of round.
I put a concrete block on top and a big chunk of wood, Piles more scraps around it and fired it up.

 



 


 

 

I ended up with about 1/2 barrel of charcoal and learned that the big chunk is too big.

I also found the barrel is not too good, when I emptied it I saw some holes in the bottom.

I'm happy with the outcome and will try it out when I smoke my turkey.

[Beau Woodworks]

Nice. 

The holes in the bottom of the barrel are not necessarily a bad thing. They will release volatile gases into the fire and aid the cooking of the charcoal far more so than the gases that escape from the lid

[SwampDonkey]

Up north its a desired firewood.  In tennesse hickory is often shunned as a firewood for a reputation of melting stoves and burning too hot.  

Rest easy Mike, we've warped many a stove with beech and rock maple. Not me personally, but I've seen a few over the years. Some of those Enterprise stoves, which were in every farm house in these parts, have been warped. That was more apparent with their wood furnaces. The old foundry closed up when she burnt to the ground. ;D

I'm intrigued by the process of making charcoal, but personally, that is as far as it gets. I love the heat of wood, but I don't have much for rock maple or yellow birch to get involved. Oak is too sparse and hickory is extinct up here. ;)