How to make charcoal?

I need to make about a cubic yard of charcoal. If it isn't created in small chunks, it will have to be beaten into small chunks, as it's for the garden.

My minimal understanding of the process is that you get a good fire going in a metal barrel or something that has some holes in the bottom, add wood or sticks or stuff like that, then mostly shut off the oxygen and let it char.

Some additional details would be great. I'm looking at trying a bag of stove pellets if no one has anything bad to say about the idea.

Sue

I find it a lot easier to use wood that is about 1/4 to 1/2 a cubic foot or so in size. For the process I use, if it is too small the fire consumes it too quickly, and if too large the center doesn't convert so well. I actually have an easier method for smaller quantities, but for the amount you need to make, I would start with about double raw wood. Dig a pit and get your fire going. Let about a third of it go to ember, your fire will be good and hot. Get a steel pipe about a yard long with a cap on one end and stick the open end near the base of the fire. Smother the fire with dirt, leaving the pipe sticking out. You want to build the fire so that it will have enough structure that the dirt won't just fall through it and fill in all the little spaces. Now here's the tricky part, you want to bake the wood for at least a few hours (hardwoods, by the way, make better charcoal for cooking purposes). If the combustion quenches completely, then the wood pile may cool too much, and it won't convert all the way. You can remove the cap to let in a little more oxygen once in a while. It is one of those things where you learn by experience what to look for, how the ground feels above the fire, etc. About half the time I end up with a decent set of charcoal, which I can break up with a hatchet or hammer easy enough. I like to use maple or alder, but I guess oak is the best for it.

My cheater method is to build a fire, use one of my dutch ovens with a tighter fitting lid, and put some wood in it and cook it charred. I can make a couple cubic feet at a time this way, and it is a lot more reliable.

Don't use aluminum. The combustion level and reactive vapors will dissolve it into your wood and it'll make a mess of it all.

Sounds like Benjamin has the best idea. I was going to say you had it about right Sue. The trick is to get the fire hot enough to cook and char the wood that's put on top without burning it completely into embers. However you do it, you're still going to have lots of ash and embers from the base fire. Use them, they'll be good for your garden soil too.

Okay, that is all making sense. Love the dutch oven idea!

Thank you.

Sue

So basically, you make char cloth, but with wood? Or is that a gross over simplification?

Umm, should be about the same approach I reckon. I suppose you could make a big batch o' char cloth by stuffing a piece of cotton clothing in a dutch oven and doing it like I would my charcoal. When I am swabbing down my dutch ovens during a seasoning session, I use cotton patches from towels and tee shirts, and they will smoke up enough that they will easily catch fire later on. They get loaded up with burnt oil/grease and turn almost black themselves. I never thought to save any of them for firemaking, but maybe I ought to give them a real test. Might've just stumbled onto something here. I can give this a spin this weekend on my bbq and let y'all know how it goes.

I have never needed to make charcoal, but you got me thinking (something I don't seem to do much of these days). I wonder, assuming that one has access to empty metal drums, if you could take a 30 gal drum, cut one end out, punch holes all around the sides (the pointed end of a pick works well for that), then fill it with some paper and your wood, and lite it off (like the burn barrels we used to be able to use in some parts of the country). Once is it burning well, take a 55 gal drum that has one end removed and turn it upside down over the smaller drum, in effect sealing the fire inside. When the oxygen inside of the drums has been consumed the combustion should stop. Kind of like a char cloth tin. I suspect that timing the snuffing part would be critical...

I think size may matter in the quality control aspects of making charcoal. The bigger the fire pits, the less consistency I seem to get from my charcoal. If you had a way of introducing a controlled amount of oxygen into the chamber, then you would be able to keep the decay process moving so that more of the wood converts without having too much charcoal turn to ash. It is all a balancing act, which is what makes the dutch oven process seem to do better. Smaller batches somewhat isolated from the direct combustion area seem to be most effective.

Given that, yours should be a viable process with substantial recovery still possible after some practice I reckon.

I guess that if one cut the bottom out of the 55 gal drum, that would leave the bungs intact on the top. One could be removed and replaced as needed, in an attempt to regulate the oxygen. Seems like too much work to me though.

Susan, could you just go to the store and by a bag of briquettes (what are those things made out of anyway?), then smash them up???

I think the brickettes are made from coal (not entirely sure). I'm also unsure whether they contain potassium which I think is what Sue is looking for for her soil.

I might be wrong on the science of this postassium/charcoal stuff (I was wrong once during a debate in 1975 ), but, in any case, I put our woodstove ash and charcoal from my daughter's marshmellow firepits into the garden and work them in first chance I get - even in winter. I read that ash losses it's ability to help the soil if it's rained on or thoroughly wetted before being worked into the soil. I don;t understand it, I just go by that.

This is waaaayyyyy off topic here, but if you are ever camping where the only "facilities" is an old one holer, if you sprinkle campfire ash in after every "deposit," you will have almost no foul odors in the privy...

Charcoal briquettes are usually made from wood (typically oak), with some petroleum components added to the cheaper brands, including coal.

Wood ash generates lye, which can be in the form of soda lye or potash (potassium lye). Potash is less common, and both forms leach from the ashes in water, which is how lye used to get extracted for making soap. Lye is caustic, so as a soil amendment you wouldn't want to apply it on foliage or the plants will get chemical burns. It is best to mix into bare soil along with organic compost, which is slightly acidic.

Charcoal has other gardening applications not associated with lye, which may be more like what Susan is considering. Hard to say until she lets us know. In any case, lye can be extracted from charcoal ashes as well, so be mindful of that if you are dispersing charcoal into your garden, you will also be likely adding a small amount of lye.

What I am attempting is an experiment in Terra Preta, the phenomenal Black Earth of the Amazonian jungle.

It seems the native people there (prior to disovery by Europeans) lived in a rain-heavy area that washed the nutrients out of the poor, acidic soil. Scientists have been trying to discover how the local tribes along the Amazon (specifically) created an incredibly rich, black soil that seems to reproduce itself.

Going by what they know of the way the people lived, farmed, and disposed of their debris, most scientists suspect that it was mostly accidental, a combination of farming practices and debris disposal. But they think that charcoal played an important part, creating a way for the nutrients to be caught and held in the charcoal, preventing the loss to the rains.

They are fairly certain that they did some low-temperature burning of their fields to reduce weeds. I think that they probably shoveled out the ash and burned bones from their fireplaces and dumped it into the fields (potash, phosphorus), kept their livestock near their huts to prevent loss to jungle animals (manure). They may have also bled out their animals there (nitrogen), and buried dead animals and possibly even people.

Some people involved in permaculture have done some small experiments, adding things like charcoal and burned gummy vegetation (done in a pot as suggested above) to their ordinary dirt that was amended with older manures. Some kept controls (all done in large planting pots) and they seem to be finding that the plants do much better with the 'homemade' amendments than regular dirt with just manures, or regular dirt with chemical fertilizers, etc.

So, I thought I would do some experiments also, but mostly in the ground, rather than pots.

And that's why I wanted to know how to make my own charcoal, and was sure that someone here would know how!

Sue

So, are you going to try any of the charcoal making methods suggested, keep researching, put the project on the back burner, what? My wife, who pretty much has a black thumb, thinks that this sounds interesting...

Jerry Baker should be reading this thread......

We used to soot our garden regularly back home. We put a lot of chikcen manure into the soil, and so to counter the acidic effect of organic decay, the ash from our fireplace (we burned about 10 cords a year) was added to it for years. Our biggest problem was too much nitrogen, which would make the spinach, radishes and lettuce bolt. I recall taking armfuls of spinach around the neighborhood to give away, stalks about an inch around at the time. Just like too much zucchini, you can overdo it on spinach in the garden too. Bolting radishes means no bulbs.

OBG, are you perhaps insinuating that I may not follow through on this? Hmmmmmm?

I like the idea of the dutch oven method, but I don't think it would make very much charcoal.

I also didn't think about charcoal being made from hardwoods. Most accessible stuff around here is fir. I'll have to look around.

A guy not far from here sells burn barrels. I think I will buy one and beat some holes in the bottom with a pick. Then I'll push a brick under one edge of the bottom to let air get under the fire, build a good hot fire with untreated 2x4s, put in a bunch of yet undetermined wood, let it get started, then put the lid on and knock the brick out from underneath and let it cook.

I have a burn barrel now, but it has holes all around it, and I don't know how to close them off other than sticking wads of aluminum foil in them, and someone said aluminum will melt.

We shall see.

Sue

I suggest hardwoods only because if you are going to use it to cook with, then you don't want to use fir. Most coniferous woods contain too much of the nasties that would taint whatever you are cooking something fierce. About the only thing I will cook over an open fire made from fir is hot dogs or marshmallows, where I can keep the food out of the path of the off gases from the combustion.

However, for your purposes, I don't see any fault with using fir. Also, it depends on how big a dutch oven you use. : ) I have or can get my hands on some pretty big ones, big enough for what you need for sure.

I had no doubt you would follow up, just wanted to prod you along a bit, so to speak. Whatcha been doing, off working or something?

I suspect that your new plan will work as well as, and maybe better, than anything suggested here so far. What are you going to use for a lid on the thing?

Awaiting further developments...

Okay, if fir will make charcoal, I'll try that.

If I plug the holes in the sides of my existing burn barrel with wads of aluminum foil, do you think they would melt?

Most burn barrels come with lids. If they aren't cut off, it's really hard to get the wood through that little hole in the top.

I've been getting my vegetable garden started, and getting some hollow concrete garden spheres ready to sell as fundraisers for a local cat rescue shelter. And this nuisance of having to work for a living is something that I find to be a constant source of irritation. But I have to be able to keep gas in the car so the dog can go for a ride.

Sue

Good luck, and be attentive. It is a fine line between ash and snuff, all based on the oxygen supply. You really have to be able to turn it off and turn it on, so to speak.

Keep us posted.

"...Most burn barrels come with lids..."

Those must be the Cadilac of burn barrels, and I have the Nash Rambler. Ours was (they outlawed them were our real home is) just an old 55 gal drum that I poked a bunch of holes in with my pick. Made a wire cover for the top, just to keep flying papers from tourching our trees...

Well, shoot! You mean I probably won't do it perfectly the first time?! Sigh. Okay, I've got 3/4 acre. By the time I've charcoaled the whole thing, I should know what I'm doing and probably won't need to do it again. Ever.

Thanks, guys!

Sue

OBG, if your wife wants to check out Terra Preta, suggest she go to the Permaculture Institute of Australia site. This link will take her to one of the threads on the subject there, but there are others, too, if she does a Search.
http://forums.permaculture.org.au/ftopic1775.php&sid=a8b9f1a2539e2fc4a7972d619bc93f17

I just peeked in over there, and there were 103 responses on the thread, plus a lot of links, too, so tell her to settle down and be prepared to spend some time.

Sue

I have never made charcoal, but on our last camping trip, we took an evening walk and came upon an old Hawaiian kiln that was used to make charcoal out of guava wood.

Sorry, not a helpful post, but just an fyi.

10-4, thanks...