Jump to content
I Forge Iron

Homemade charcoal

Recommended Posts

Good evening all from the Buckeye state.

I just saw the new blueprint on homemade charcoal. I found it quite interesting in the fact that it brought back the memory of MANY years ago when I first made charcoal.
I started blacksmithing at around 14. Now, I had the same problem then as I do now. Not so much money. (As a side note, I have never had the problem of "spare change."
Anyway, my coal copnsumption was rising alot faster than my meager income at the time.So the decsion was made to make my own charcoal. I mean, heck, that's what was the first smithes used right. So I settled on a very similar design as the blue prints. I loaded up a 55 gallon barrel with cut up pallets, honeysuckle brush, anything else remotely woody. I capped the barrel with it's cap and turned it on it's side on two liberated street sign posts over a fire. I let it cook for a rather long period of time,, three plus hours I think. I didn't have to keep the fire roaring,, just steady. I left the small bung on the barrel top open to let the gasses escape. Which by the way, the gases that are released during coaling are VERY volitile, so watch out everyone. As another side note, there were fuel systems developed during WWII that used charcoal producer gas..

ANYWAY, I let it cool opened it up and much to my suprise it worked perfectly. I had alot of very nice charcoal for my efforts. Not bad for a 14 year old.
There is a publishing compant called Lindsay Books that has a nice book on homemade charcoal making for those interested.
So people,, the you have it. Watch for me in the future as I start buildingg a new shop. I hope to post all my construction progress here.

Yours truly

Phil Patrick

Link to comment
Share on other sites


Charcoaling is pretty easy as you discovered early. You're only missing one bet with your drum retort.

If you put the open bung at the bottom and add a little plumbing, nipple, elbow, nipple elbow and a longer nipple to direct the volitile gasses bach under the drum they'll burn so you don't have to feed the fire more wood.

The next thing you want to try is covering the drum with a little sheet steel. Leave about a 2" gap between the drum and the sheeting so the heat will be evenly distributed. This will reflect much of the combustion heat back onto the drum and lower your initial fuel requirements.

The next step is covering the sheating with a few inches of soil (Mineral soil! organic soil will burn.) to provide insulation and you'll reduce your fuel requirements further.

The reason you want to reduce your fuel requirements as much as possible is simple. the less wood you burn for heat, the more you'll be able to convert to charcoal.

Another tip is to split the wood to 3" or less cross section. Thicker than this and you'll burn more up trying to convert it. Length is unimportant but thickness is.

Another myth is hardwood vs. softwood. It all makes perfectly useable charcoal. the only significant difference is the carbon vs. mineral ratio. Some woods have a large percentage of silicates or other other non-combustible minerals, ironwood being a good example. There can be significant differences even within a species. Here, in Alaska willow makes excellent charcoal but in many regions willow has so high a mineral content it's nearly useless.

As a rule of thumb however, the heavier the wood the more carbon per volume and the better yield you'll get per drumfull. This isn't always true but it's a fair rule of thumb. If you don't have anything else available softwoods: pine, spruce, etc. will work fine you just won't have as many lbs of charcoal at the end of the burn.

Avoid the cedar family as they have natural toxins in their sap. Insecticides to be more precise and the fumes are noxious to say the least though not necessarily dangerous.

Be VERY careful using viney or woody brush, if you accidently try coaling poison ivey, sumac, oak, etc. you'll be in for a NASTY experience.


Link to comment
Share on other sites


I don't really know how to answer your question as to specific woods. I've done some charcoaling for my own use and read a bit. The part about mineral content is valid, as is the part about density. If you lived down the road from me I could point to the trees to cut and the ones to ignore.

Wood knots tend to have a higher concentration of pitch which would mean longer cooking time in the retort and more charcoal lost. So logic tells me that rule of thumb is probably right. I wouldn't get too excited about a few knots though, especially if it's lumber, say 1x stock. It'd be thin enough to cook quickly.

Not knowing the particulars I'd go for clear hardwoods, maple, oak, alder, etc. Pallets are, or used to be, scrub oak and make, or made good, charcoal.

What kind of return you get depends on the method. There are two basic charcoaling methods: direct and indirect.

The direct method uses the wood itself as the fuel. In it's crudest form you can simply rake the coals out of the campfire and quench them. The colliers of old used a more sophisticated version of direct conversion by packing split, seasoned cordwood tightly in a pit or mound and covering it with dirt and leaves. They then lit the stack from the top, center and carefully managed the smoldering fire by opening and closing airways, smoke holes, etc. this typically took a few days to a week depending on how many cord were being charcoaled. This URL shows this method. Regia Anglorum - Charcoal burning in Anglo-Saxon and Viking Age England

The indirect method involves putting the wood in a sealed container and heating it externally. The steel drum method is indirect or retort charcoaling and produces a higher yield. This URL shows a 55gl drum retort. Do NOT use concrete block to enclose the retort like he did. Concrete will spall apart at these heats. Charcoal Retort

Okay, don't hold me to these numbers they're off the top of my head. Well controlled direct charcoaling yields up to around 50% by weight. Indirect can yield up to to 70%. This includes the fuel burned to get the volitiles boiling off enough to serve as the retort's fuel. Self sustained reaction in other words.

So, the short answer is if you keep a close watch you should have at least half a drum of charcoal when you're done and with some practice less than 3/4 of product. O'Conner appears to have gotten about a 4o% yield counting the wood burned initially.

You also want decent sized pieces of charcoal, little crumbs will blow out of your forge, wood of 2x4 size is nearly perfect. 4x4 is a little too thick and you'll have some unconverted wood left in the drum. This isn't a real problem as it'll convert in your forge but you'll be getting flames and smoke in the process.


Link to comment
Share on other sites


If I lived down the road from you, I'd need those trees to stay warm!:P

I was curious if folks just toss a bunch of wood into a barrel, let it burn and cover, or if folks use specific wood. The maple I have is much harder so I would imagine would produce heavier charcoal than pine, and isn't light and fluffy what most folks are after?

Link to comment
Share on other sites

My favorite charcoal hands down is Pine, but any hardwood or softwood will work. I do use allot of construction scraps ( 2x4 & 2x6 drops ) As well as tons of the perfectly sized hard maple scraps that I get from a local broom & brush factory. $10.00 for a pickup load of kiln dried maple is a deal in my book. The hardwood charcoal seems to burn longer, but if I get a really nice crispy batch of pine charcoal I'm in forge welding heaven.


Link to comment
Share on other sites

my only advice is to remember the advice from the blueprints... paraphrased: unless you have a hydraulic splitter, stay away from the elm and hedge (osage orange). I can personally attest that once upon a time a young boy saw his dad splitting oak with a splitting maul, and then decided that he could do just as well....except that poor young boy grabbed a piece of rock elm, and the father just couldn't find it in his heart to stop laughing long enough to explain to the boy that rock elm just doesn't split that easy...

Link to comment
Share on other sites

Well Alan if you lived down the road from me you'd probably have natural gas heat with a wood stove to supplement and as backup. It was -6f here this morning and will probably get close to -10 tonight.

Sure, there's a method called semi-direct where you fill the barrel or really large container, light it and when it gets burnig good cover it up. Yields fall between direct and indirect conversion.

I see votes cast for softwood as hotter if shorter lived in the forge. I can't really say as my main forges have always been propane or coal. I've used charcoal but not enough to have an informed opinion.

However the comments do bring to mind heating with wood. My folks used to live in the Sierras NW of Reno and heated with wood. It was a large house, 3,400 sq/ft as I recall. On really cold mornings when they wanted a lot of heat Dad would toss a small piece of red fir in the stove. When I say small I mean a split piece less than 3" thick and maybe 16" long. That little piece of red fir would just flat run you away from the stove and in no time you'd be cracking windows for some relief. It would flare quickly and reduce to charcoal in maybe 10 minutes then that pile of charcoal would just COOK for an hour or so.

Maybe somebody on the forum lives where red fir grows and can let us know how it works in a forge.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...