Making and using biochar, results too!

Do you buy your biochar or make your own?

If you make your own, please describe the steps, materials, equipment, temperatures if known, and time needed to make it.

If you have used biochar, please indicate the type of biochar, the % you put in the soil and if you tilled it or layered it. Did you try it in a pot for a potted plant?

What were the results if known.

What plants did best with it and what ones did not do so well.

Did you use any other soil amendments in addition to biochar?

Biochar looks promising. It has been touted as a way to help sequester atmospheric carbon.
Some places use it to clean up contaminants.

Your information, opinions, and thoughts are desired!

Many thanks!

In my never ending quest for moisture control (I HATE having to water), I ran across Biochar.

It is supposed to be 2,000 year old technology.

Some call it Terra Preta (or Amazonian black earth) and some call it African black Earth.

Reports indicate that it make weakly fertile soil more fertile.

What I was after is the part concerning moisture control.

I made some biochar out of twigs and new paint cans.

Takes as long to break the twigs into a small size than worth the trouble.
Paint cans don't hold up so well so I bought an 8 quart stainless steel pot with stainless steel lid.

So far so good. Except for a tiny problem.
The stainless steel handles were riveted on with aluminum rivets and the aluminum melted off!

Tossed that batch of biochar on the lawn ( Grrrrr ).
So had to buy some machine screws, lock washers, and nuts then reattach all the handles.

Hooray! It stayed together!

I then tried old Pecans. The oil in them has a high flash point. Gases burn HOT HOT HOT too.
Ran out of them and then I researched hardwood pellets.

I found out they grind up wood into a fine dust, steam it, press it into a mold, and dry it to less than 10% moisture content (drier is better).
I bought 100% oak wood pellets, all natural (it says on the bag). 40 pound bag too. I get the extra heat from them and the charcoal as a bonus plus little to no ashes to dispose of. One bag has 35K BTU of heat energy in it.

I filled the container full, tossed the lid on it, then placed it inside the wood burner that heats the space. Takes about 1 1/2 to 2 1/2 hours to pyrolize (dependent on how hot the stove is).

Umm. another hitch. It expanded and lifted the lid an inch!
I managed to get the lid back down after an hour of burning.

I used to take it out when it was finished flaming to let it cool.
Takes too long.

So I take it out of the wood burner and slowly pour the char into a bucket of solution. That is called quenching. It helps fracture the charcoal to give it even more surface area.

OUCH! The steam surged off it it like crazy. Burnt my under forearm in the process. Leather gloves are a MUST! Preferably gauntlet style welder's gloves.

Now I scoop a few at a time with an ash shovel into the solution - SLOWLY.

Not only does it eject scalding hot steam, it ejects charcoal dust everywhere if you go too fast.

Messy messy messy...

It does the Rice Crispy thing too sometimes - snap, crackle, and pop!

I push the charcoal under the water repeatedly with that metal ash shovel to ensure it is wet and there are not hot coals left. Charcoal is hydrophobic (resists water).

The quenching also draws in the solution.

After a short while I scoop out the cool biochar and place it into a colander above another bucket to strain out excess solution.

Once it stops dripping, I toss that into another plastic bucket and use a piece of wood from a wooden handrail to smash (gently) the particles into finer particles about the size of grains of salt on a hot pretzel. I try to make them no more than 1/8 inch in size or smaller.
Smashing smaller takes a lot more time too.

Ideally you want variable sizes if you can.

I then dump that into another 5 gal bucket and process some more.

After the 3rd or 4th batch, I sprinkle some wheat flour (handful) on the biochar and a handful of organic fertilizer. I mix well.

Repeating the process from start to finish until the bucket is full.

In the solution, I use rain water, sulfur free molasses, and a cup of comfrey tea I have been bubbling for a few months.

I also add in some apple cider vinegar with mother too.

(Holds thumb up and says to self: that amount looks about right- which is about 2-3 ounces of molasses, about 1/2 to 1 cup apple cider vinegar with mother depending on if it is a mostly full bucket of rain water or 1/2 full)

Although the hot charcoal will kill off some of the goodies in there, it won't kill them all.

Once I get the amount of biochar I need for a given spot, I progress to either layering it in or tilling it in by hand. Can always top dress later but it won't do much until it is in the soil.

I am trying both layering and tilling. Not top dressing at this time.

5 gal bucket will do a row 5 inches wide, 1 inch deep, and about 10-12 feet long. Dimensions are approximate.

Rule of thumb is you would try to get about 10% biochar into the soil.

Research how much for your situation for better results.

I suggest you start out with a low percentage as it is difficult to reduce the biochar if you use too much.

I have about 10% on a 3 foot by 8 foot patch of garden space. That is reserved for the wifey's flowers - but will sneak and plant some lettuce or radishes untill after last frost date.

I am trying to make enough to do my whole hugelgarden too but it takes a whopping amount to make that one inch layer for an 800 sq ft hugelgarden.

One site sells 5 gal buckets of it for $59. I can make it for $5/bag of wood pellets times two. Takes about two bags to make one 5 gal bucket.


Note: Inoculating and activation are two different things. Simply adding things to make the biochar is not activating it. That takes time and warm soil (I think above 50F) to activate it. The time is roughly 3 months to two YEARS depending on the situation. So patience is definitely a virtue!


This for me is a very LOOOONNGG slow process as I can only make about 2 quarts at a time.

But hey, it is winter time and can't do much else so why not?

Mixing in the biochar now while it is cold saves me time for when the soil warms and I can plant again. The biochar can still draw minerals to it while I wait.

Think of it like the biochar is a magnet and the minerals are like iron filings.

Microbes and fungi will still be dormant though.

You may want to put some worm castings tea or compost tea in the area to help things along.

I have given out 1 cup zip lock baggies to several people with the biochar in it.
I write on the bag Biochar - DO NOT EAT! And to mix it with 8 cups of soil or planting medium.

I also suggest they do two pots - one with the mix and one without to see any difference.

Won't know anything for several months at least.


Almost forgot.
Classify your biochar as copper.
There will be biochar 'sludge' in the bottom of the solution bucket after multiple batches.
I classify that as gold.
The black biochar solution left over I classify that at platinum (smallest particles biggest surface area).

I can mix the platinum biochar into water and use a watering can that will apply it without digging! YEA! No sore back!

Those smaller particles will actually get in between soil particles for added benefit.

Be aware, the smaller the particles the more you will lose over time.
Worms and other soil critters consume some of it and take it elsewhere. Rain can wash some out.

You can lose up to 17% of your biochar.

Maybe the sandier the soil the bigger the particles?

My research suggests that the poorer the soil (and sandier) the greater the benefit. Benefit can be as much as 400% by some estimates.

Good rich soil may not see any benefit or very little.

The 10% mix is a starting place. Some use 20%, 30%, even 40% to get results.

Isn't experimenting with things FUN?!!

I look forward to your experiences, knowledge, and any suggestions.

Thanks!

I've been making my own since last fall, although I haven't gotten around to using it yet.

I make most of mine in the wood stove, out of crop debris like corn cobs or sunflower seed shells. This last fall was so damp I ended up pulling up my bean plants whole and having them dry indoors, so I had lots of bean vines to turn into charcoal, along with the empty pods.

I use small retorts made from empty soup cans. Use a side-cutting can opener so that the lid sits neatly back in place. After emptying and rinsing out the can, punch a ventilation hold near the top. I find a handle helps, so I also punch 2 more holes near the top and thread a piece of fence wire through it. And that's it, ready to go. Since most soup cans have a plastic coating on the inside, I like to burn them once while empty before using them.

To use them, load it up with whatever burnables you're turning into charcoal, set the lid in place, and put the can in a hot fire. I don't pay much attention to temperatures, although I've noticed I get better charcoal if the can is directly on the hot coals. I give it at least 30 minutes, sometimes an hour. When the can stops smoking, it should be done (although sometimes it cools down more than I expected and quits that way). I set mine under the woodstove to cool, although you can douse them with water if you want.When they've cooled down enough to touch, open the lid and give it a sniff. Half-cooked charcoal stinks, but finished charcoal has little or no odor. If it needs more cooking, just put it back in the fire. If it's done, I pour it into a metal canister and refill the can for the next batch.

If you heat with wood, you can make a lot of charcoal this way, just a little at a time.

There's another way I'm planning to make charcoal, although I haven't done a full burn yet. I have a steel bucket sawdust toilet out on my land. I had originally planned to use a beefed-up solar oven to bake the contents into charcoal, but had some trouble getting that hot enough. Now I have a portable rocket stove for use there, but the weather turned snowy enough it'll have to wait until spring, when the shed with that toilet is accessible again.

I went that route because I needed a toilet out there, but the terrain isn't suitable for humanure composting, and the ground is too hard to dig a latrine by hand. I figured this way, I could use one problem to solve another, because I wanted a ton of biochar for my field.

You were asking for input on made vs bought char. I'm actually going to be doing a research project this summer comparing different types of biochar, including homemade vs bought. I'm curious to see the differences as well.

I have noticed that the smaller the stock material the harder it is to convert. Seems there needs to be some gaps between the particles.
Coffee grounds are the hardest I found so far.

I figure it costs me about $15 to make a 5 gal bucket of the stuff.
Most places I researched want around $59 for a 5 gal bucket.
A 5 gal bucket holds about .667 cubic feet.

Of course there are some that will sell larger quantities cheaper than that rate. I have seen $2500/ton prices.

About the stock material.
Woody material, especially hardwoods from what I read, have the most pores but the least minerals left over.

'Greens' and similar have the least pores but the most minerals left over.

Bark is one of the best of the two worlds as you get more pores and more minerals left over.

Very high temperatures (around 900c) give less charcoal but more pores.
Low temperatures give the most charcoal but not so much pore wise.

And too hot will cause the carbon to actually melt.

Stainless steel glows red about 600C.

From what I read about 250-450C is more optimal.

I have read, on this site even, that temperatures in excess of 450C are necessary to vapourise all the volatiles. 250C would be much too cold, and would leave much of the porous carbon structure filled with the byproducts of low-temperature pyrolysis.

I don't think I would pyrolyse coffee grounds. They are essentially ground and leached seed matter, and worms go apeshit over the stuff. Charring it seems wasteful and unnecessary.

One backyard idea that I haven't had the opportunity to play with is where I set up a retort made from a 55 gallon drum that I build with an internal rocketstove riser and external feed, such that the operation of the rocketstove keeps the outer chamber of the drum, which I would fill with biomass, oxygen-free and heated to over 450C. I would want a pressure valve that exhausts into the burn tunnel, such that any buildup of gasses within the retort gets redirected to fuelling the burn. I would also want an appropriate temperature probe, but I suppose that if the drum were to start glowing cherry-red, then I would know that it had gotten sufficiently hot.

After attaining the correct temperature, I would allow the fuel in the burn tunnel to become exhausted, which would make it clear if any volatiles were exiting the retort (the flame would be a dead giveaway). I would then pop the lid off with an appropriately long handle and douse the activated charcoal with water, opening a drain port in the bottom near one side. I would then either compost with the resultant char, inoculating it, or I would do it faster, by preparing some actively aerated compost extract and dousing the batch with it, probably mixed in with a carbonaceous and nitrogenous mix of food sources, say hay or woodchips and coffee grounds or composted ruminant manure. I would also prepare and apply a fungal slurry, with species chosen based on the substrate added to the char.

One of my favourite setups is the kon-tiki.



But I love the stainless-steel-container-in-the-woodstove method, too. It's the ultimate in function stacking and efficient char production, as some of the heat produced by the combusted volatiles actually goes to heating the space, too, rather than just warming the atmosphere.

Good job. Send photos. Keep us posted, and good luck.

-CK

Rather hard to make compost tea right now due to the lack of materials related to it being winter time.

About the temps.
I have no way of know what they are except for this:

If the stainless steel pot glows red, I know it is above 600C.

The finished charcoal - if it floats on the water, temps were too low.
If it sinks, it is at least good enough to use.

I still smash the particles either way to make them smaller.
Even cold temp production can benefit from that.

From what I read elsewhere, seems that the leftovers 'clogging' the biochar from cold conversion are considered food for microbes and such.
One would assume that the microbes would eat the leftovers and open up the biochar pores.

I will try to get some pictures when I can get back to making more here in a day or two.

Hibernating right now due to low wind chills and low temps.

The wood burner I use is very old. About 40 or 50 years old.
It is about 5.5 cu foot in capacity.
Perfect for heating and making biochar with my setup.

Once the weather breaks and no wood burner needed, I have to find another means of production outside.

Barrels and piping would cost me about $200 to buy.
Precious seasoned wood is hard to come by here.
Would hate to waste that when it could be saved for next winter's heating needs. Also have to consider where I live and if that kind of conversion is permitted. Inside a wood burner they never know! LOL

Just hate wasting all that energy.

That container I use is about the same as putting one oak log in the burner.
So yes, I do get some heat out of it. Lasts between 1 1/2 to 2 1/2 hours. Almost no ash and get the charcoal in the same process.

Just wish I had a way to vent the gases for combustion to underneath the pot instead of at the top.

More of a closed loop system I would think.

Seems hardware stores here so not sell stainless steel plumber's strap.
I tried with plain steel but that lasts a few burns then it is so weak and brittle it breaks.

But the tests did seem to put out more heat and faster conversion.


About coffee grounds.
They are wet from public water and that contains chloramine.
I get them from coffee houses and can usually get 100 to 300 pounds or more at a time. For free. Far more than I can use in the garden.

No place to dry them out for garden use right now.

Coffee ground particles mean LESS smashing of the charcoal too. And are about the right size for application.

This is the pot I used:
https://www.walmart.com/ip/Mainstays-Stainless-Steel-8-Quart-Stock-Pot-with-Lid/37320201?selected=true

Unfortunately they used aluminum rivets which melted. So replaced them with steel screws, lock washers, and nuts.

Lid does not fit real tight either. Plenty of slop in it for safety.

Lasts a whole lot LONGER than steel paint cans.

I do have to keep it heated for it to produce the gases though.

I wonder what happens if you quench biochar then reheat it a 2nd time.
Would it leave more minerals in it?

For those with newer (and smaller) wood stoves, you can make or buy a 'BioCharlie' or use restaurant prep table pans with lids (EXPENSIVE).

I was trying to come up with a way to use a rocket stove to make it but feeding sticks in there constantly for hours is something I don't want to do.

Here is a pic a friend took for me.
I will upload more later when I get the chance.

Here are some the things I use to make my biochar.

EDIT: the shiny thing is a dime I put there for size comparison. But the biochar does have varying sizes.

Ellendra Nauriel wrote:I've been making my own since last fall, although I haven't gotten around to using it yet.

Mixing it into the soil now allows the biochar to attract minerals before planting. The sooner the better! Remember, it takes time for biochar to situate things.
Winter snow/rain does wash out some of the minerals. Why not let the biochar hang onto them for you while you wait for planting season?

Microbes and such will just remain dormant till the soil warms. Putting the biochar in as early as you can speeds the benefits up a bit.

I plan on using well water (already has minerals in it, dissolved) instead of rain water.
I will augment the soil with worm castings too. And coffee grounds as a top dressing.

On a very quiet night I expect to HEAR my plants growing! lol

Or at least the worms chanting my name in gratitude for the coffee grounds...

I may be stuck buying some red worms as my garden only had 3 in it when we were working on it.

Might even buy some night crawlers too.

Mixing it into the soil now allows the biochar to attract minerals before planting. The sooner the better! Remember, it takes time for biochar to situate things.
Winter snow/rain does wash out some of the minerals. Why not let the biochar hang onto them for you while you wait for planting season?

Picture an ice skating rink.

Now picture that rink tilted at a 45-degree slope, with parts of it even steeper.

That is my land in winter. My garden starts about 800 feet up the hillside.

Yeah, not going out there until the ice melts.

Ellendra Nauriel wrote:

Mixing it into the soil now allows the biochar to attract minerals before planting. The sooner the better! Remember, it takes time for biochar to situate things.
Winter snow/rain does wash out some of the minerals. Why not let the biochar hang onto them for you while you wait for planting season?

Picture an ice skating rink.

Now picture that rink tilted at a 45-degree slope, with parts of it even steeper.

That is my land in winter. My garden starts about 800 feet up the hillside.

Yeah, not going out there until the ice melts.

Did you know that wood ashes can melt snow?


Lots of uses for wood ashes.

Here is one reason for various particle sizes:

https://www.sciencedirect.com/science/article/pii/S0022169415009464

And another study:

https://www.ncbi.nlm.nih.gov/pubmed/28598988

Hello Kai,
You asked some great questions and came up with some interesting points of view. Many of your questions have been answered if you read through the other threads in this forum.
Thanks,
John S
PDX OR

Kai,  I love what your doing with biochar.
I have made it in a bonfire by stuffing an old steel toolbox with bones, twigs,  and such.
I have also built a TLUD stove from a stainless steel 16 quarter stock pot.
I got my stock pot from harbor freight,  as the biggest of of a 4 part set,   for 25 bucks,  with coupon 20 plus tax .

I plan on using it the TLUD to fire a BBQ I've turned into a pizza oven.
Originally I was going to fire it with a rocket stove, and I still might,  but TLUD's offer long even heat,  and, biochar.

Maybe you could use a TLUD for   outdoor cooking, canning,or distilling.
When none of those things are needed,  drying feedstock  for the next batch could be useful.
A TLUD fired "white " oven could be filled with biochar feedstock and tapped to redirect the gasses back into the flames.

The person behind the YouTube channel Permaculture Playground is doing great work with indoor TLUD stoves.
Their latest iteration includes mass,  making it a TLUD mass heater.

I've considered buying the largest stainless steel mixing bowl available for use as a "cone" retort, but video from the purveyor of Skillcult has me convinced that a trench system is cheaper and takes less labor.
Still a big enough bowl would make for a nice fire pit.
A second smaller bowl,  inverted in the first,  could form a closed retort.

William Bronson wrote:Kai,  I love what your doing with biochar.
I have made it in a bonfire by stuffing an old steel toolbox with bones, twigs,  and such.
I have also built a TLUD stove from a stainless steel 16 quarter stock pot.
I got my stock pot from harbor freight,  as the biggest of of a 4 part set,   for 25 bucks,  with coupon 20 plus tax .

I plan on using it the TLUD to fire a BBQ I've turned into a pizza oven.
Originally I was going to fire it with a rocket stove, and I still might,  but TLUD's offer long even heat,  and, biochar.

Maybe you could use a TLUD for   outdoor cooking, canning,or distilling.
When none of those things are needed,  drying feedstock  for the next batch could be useful.
A TLUD fired "white " oven could be filled with biochar feedstock and tapped to redirect the gasses back into the flames.

The person behind the YouTube channel Permaculture Playground is doing great work with indoor TLUD stoves.
Their latest iteration includes mass,  making it a TLUD mass heater.

I've considered buying the largest stainless steel mixing bowl available for use as a "cone" retort, but video from the purveyor of Skillcult has me convinced that a trench system is cheaper and takes less labor.
Still a big enough bowl would make for a nice fire pit.
A second smaller bowl,  inverted in the first,  could form a closed retort.

Can you upload some pictures for everyone?

I am curious how you used your 16 quart one.
Making 3 quarts at a time is rather shall I say boring?

I thought about maybe drilling holes in the bottom of the container and lighting the top.
Not sure that would work though.
It would if I could engineer a resealable lid for it.

With the method I am using, I have virtually no visible ash.
Just wish I had a cheap way to direct the gases under the container for a positive feedback process. Would need a lot less wood in the wood stove to do it.

When the weather breaks and I no longer can use the wood stove for heating, I need an easy way to make it outside QUICKLY.

I am not allowed to dig a trench. And buying barrels and such are not practical for me.

Was thinking about some kind of rocket stove but feeding twigs in constantly is not what I want to do.

At the rate I am making it, I will only have about 2% in my garden. And that won't be enough to cover the entire garden either.
Just a good portion of it.

I figure *some* is better than *none*.

Trying to keep the cost down if I can.
What do I do with the equipment once I am done with the project?
Not profitable to make biochar to sell with such small batches.

Here is how one person makes charcoal and heats his home at the same time:
Small batches but hey? You got all winter with little to do out in the garden so why not make the stuff?
And save on heating at the same time!

Kai , I will try to post a photo of the TLUD.
I punched holes in the bottom,  cut a hole in the lid, and  attached an empty  #10 can as chimney.
I fill it to almost an inch of the lid with pellets , douse the top with accelerant and   light.
When I'm sure its lit, I cover it with the lid/chimney.
It burns about 45 mins, or an hour, I think, its been a while.
To tell how far down the flame front has progressed,  I mist the sides with a spray bottle of water ,which instantly evaporates from the hot spots.

Anyone looking at this thread should check this other thread out:
Indoor biochar producing TLUD gasifie

William Bronson wrote:Anyone looking at this thread should check this other thread out:
Indoor biochar producing TLUD gasifie

I getno audio when viewing from this site but if I go to youtube, everything works.

His setup is pretty darned nice too!

I try to avoid using electricity as much as I can whereas he uses a blower.
And an accelerant to get it going?

Yeah,  he does use a blower.
I'm kinda torn on using electricity on woodburners,.
I like the idea if self sufficiency, and needing electric reduces that.
OTOH, considering I have had little luck running a TLUD without wood pellets , self sufficiency is not really doable anyway.

Here are some photos of my 4 gallon TLUD:

I use a 55 gallon TLUD.  I found that it makes a lot more biochar and I can get a free one pretty easily.
John S
PDX OR

John,  what do you burn in your 55 gallon TLUD?
I am focused on shorter TLUD's because I want to tap the heat for cooking, but I would like to build a bigger one as well.
I would like to use branches without too much processing, but I'm under the impression that that TLUD fuel needs to be regularly shaped, as in pellets or chips.

Because of that,  I've leaned toward retorts for charring irregular chunks and branches.

If you are getting results  charring  chunks and branches in a TLUD, I would like to know more.

William Bronson wrote: John,  what do you burn in your 55 gallon TLUD?
I am focused on shorter TLUD's because I want to tap the heat for cooking, but I would like to build a bigger one as well.
I would like to use branches without too much processing, but I'm under the impression that that TLUD fuel needs to be regularly shaped, as in pellets or chips.

Because of that,  I've leaned toward retorts for charring irregular chunks and branches.

If you are getting results  charring  chunks and branches in a TLUD, I would like to know more.

I use tree branches and scrap 2x2 and 2x4 boards that I get from a company that leaves them out for people to use for firewood.  I never use anything that is anywhere near standard, either in length or width.  

I sometimes use a plain 55 gal drum, other times I use a drum approx 30 gals inside the 55 gal drum as a retort.  Both ways work well but if you use a retort,you can just start it and leave.  Come back in the morning and you have charcoal that is cooled and ready to go.

I can take pictures next time I do it, but this is the way I like best.  Take a 30 or so gal drum that has one end cut out.  Set it on a brick or something to raise it up a foot or so.  Fill it with scraps of wood or bones or whatever you are converting to charcoal.  The other drum is 55 gals and has one end cut out.  The other end has holes drilled or cut into it all the way around at the very bottom.  Make a hole every 4 or 5 inches all the way around.  Take the 55 gal drum and tip it upside down.  Drop it over your 30 gal drum.  Since you have the 30 gal drum raised, you will be able to reach under the 55 gal drum and hold the 30 gal drum tight to the bottom of the 55 gal drum.  Tip them over slowly and stand the 55 gal drum up on it's bottom.  Now your 55 gal drum is right-side up again, the drilled holes are on the end that is on the ground, and the 30 gal drum is upside down, full of wood, and sitting on the bottom of the 55 gal drum.  Scoot the 30 gal drum to the center of the 55 gal drum.  Now fill the 55 gal drum full of scrap wood.  Light it.  It will take a while, but when the wood in the 30 gal drum gets hot enough, gases will escape from under it.  These gases will escape into the 55 gal drum and be burned.  You can see the gas burning as it comes out from under the drum.  In order to get a complete burn, you will need to add more wood to the 55 gal drum.  I just wait until the 55 gal drum has burned down to about 1/3 full and gases are coming from the 30 gal drum and burning well, and fill the 55 gal drum up with wood again level with the 30 gal drum.  After that, you can just leave it alone.  When the gases are all out of the wood in the small drum, the drum is tight enough to the bottom of the 55 gal drum that it won't continue to burn up your charcoal.  By morning, you will have a batch of really beautiful charcoal.

I'm not sure if I explained that well, but I can assure you, the process is very simple.  I could show you in far less time than it took to try to explain it.  I need to make another batch soon, probably this weekend, I'll take pictures when I do.

Would like to chuck in my 2c.
Here in Spain we have 200 olive trees that need pruning every year. After taking out the bigger branches for the wood stove, we are left with the smaller stuff. Leaves go to the goats and then we are left with a heck of a lot of small branches and sticks.
Our quick and dirty method involves burning this in an open bonfire, as fast as we can, and then putting it out as soon as the flames have died down.
We are then left with piles of charcoal - literally wheelbarrows of the stuff - which we then put into 100 litre barrels with nettles, borage and as many weeds as we can find, before topping it up with water. We let it sit in the sun for two months, stirring it every week or so.
The liquid is used as compost tea, and the weed/char mix is put onto the vegetable beds.
Not very scientific, but works well enough, and is not too time-consuming.
We use borage as it grows wild here, and is not dissimilar in constituents to comfrey which we cannot grow.

William Bronson wrote: Yeah,  he does use a blower.
I'm kinda torn on using electricity on woodburners,.
I like the idea if self sufficiency, and needing electric reduces that.
OTOH, considering I have had little luck running a TLUD without wood pellets , self sufficiency is not really doable anyway.

I have seen hand-cranked blowers available. I don't know if it would be worth the work to use it on a TLUD, but it would be an option.

Kai, everyone,

I made a very simple experimental TLUD kiln that I detailed in a thread HERE:

https://permies.com/t/72466/Cheap-easy-mini-homemade-biochar

I only made 1 soup can of biochar per batch, but the process was super simple.

I basically made the TLUD out of a 1gal paint can and 3 soup cans.  It does get HOT, but honestly, it was pretty fun.

Hope this helps,

Eric

Like Chris,
I just burn what I have to prune every year.  I have a mature food forest, so there is plenty. I am trying to hit the perfect balance of enough shade and enough sun in the food forest.   I try to cut the pruning pieces into roughly equal sizes, as we've talked about before.  I fill it up, but leave gaps for air. I burn in the summer, because the ground is too wet to burn very efficiently during the other times of the year.  I cook a little bit of carrots and potatoes on top in a sardine can,  but it's mostly to make the biochar.  The tall chimney helps it burn the gases efficiently.   I quench it when the flames have died down to almost the level of the wood. THen I get really great, light, metallic sounding biochar and very little ash.  I will pour the quench water on plants that could like it but I sure grind and inoculate the biochar itself.  It works really well.  As we've talked about in other threads, people optimally can tailor it to their situations. Some get summer rain. Others have dry summers.  SOme people have a source of wood/ organic material other than their trees, some have acreage, Some (like me) don't. I love the flexibility of applying the basic idea to your individual situation and making it work well.
John S
PDX OR

Trace, you seem to be saying that your 30 gallon retort burns can be left alone at a certain point, but the tlud needs tending.
How long does your 55 gallon  TLUD burn?

John,  you mentioned letting the flames die down to the level of the wood.
How do you see what's going on with the lid and chimney on place?
How long does a 55 gallon  TLUD burn for you?

The volume of wood waste I get is relatively minimal.
I can easily use it on paths,  in ditches,  or at the bottom of beds.
If I'm going to the trouble of making charcoal, I want to make use of the heat produced during pyrolysis.
If I'm going to need to tend to a fire,a rocket stove seem more efficient.

The height of of a 55 gallon TLUD could make using the heat if pyrolysis difficult but the volume of a 55 gallon TLUD makes it attractive.
Cutting the barrel in half or dropping it in a hole could address the height issue.

William Bronson wrote:Trace, you seem to be saying that your 30 gallon retort burns can be left alone at a certain point, but the tlud needs tending.
How long does your 55 gallon  TLUD burn?

The 55 gal TLUD can take 3 or 4 hours or even more.  And that is correct, the TLUD needs more tending.  There is kind of a learning curve too.  If you stop your burn too soon, you will get a lot of brands, or pieces that aren't all the way to charcoal yet.  If you let it burn too long, you will get some ash.  The way I use the TLUD is to keep an eye on the holes at the bottom of your barrel and when the wood you can see thru the hole is all the way to a glowing red ember, it's time to cover that hole with dirt.  The wood will burn all the way down in some areas before others, so you have to keep an eye on the holes.  You will also probably need to add some kindling once in awhile to keep a flame going to burn the gases off.  When the wood gets burned down pretty far, you will usually get a time where the fire goes partway out and you will get heavy black smoke.  If you throw some very small stuff in and get that burning, you can keep the smoke burned off.  It may be that bigger air holes would keep this from happening, but you don't want the holes to be too big, or you will burn off more of your wood rather than making charcoal out of it.  Once you have covered all the holes, you can put a lid on to stop the process or you can quench it at that point.  It isn't hard to do at all, and I still use my TLUD sometimes, but I get better, more uniform results with the retort and I rarely get any brands.  That said, babysitting a TLUD is pretty relaxing work and not at all a chore for me.  One more thing, when I use my TLUD, I don't usually use a chimney on it.  If you want to, I would use an entire 55 gal barrel with both ends cut out as a chimney.  this one will need holes drilled around the bottom too.  That will let enough air in for a "second burn".  That is, it will let enough air in for the smoke to ignite again higher up and burn off, rather than smoking.  If you do get smoke, you can put a burning stick or what have you into one of the holes and light the smoke to burn it off.  I haven't had good luck with a chimney made smaller than that.  I tried making a tall one from 6 inch stove pipe, but it was too restrictive and I got a lot of smoke.  It did better with no chimney at all.

I adapted a  fairly flat rectangular piece of metal that I put on over the open barrel top but beneath the chimney.  It leaves a gap of about 1 inch or so, enough to see if the flames are dying down.  You can hear it too to see if it's getting close.  It works well for me.  
John S
PDX OR

Oh and I leave air spaces so it takes about 2 hours for me to burn the 55 gallon TLUD.  Very easily predictable by watching just a bit. Mostly reading and relaxing.
John S
PDX OR

Hallo,
I have a large ammout of prunned vines from my vineyard every winter.. I have chopped them on garden electric garden chipper till last year, but since I already have another regular source of large ammount of woodchips, I decided to turn the prunned vines into biochar by using 25 gallon garbage can with a sparse grate and air holes in the middle (see Picture 1). Vines were combusted in the upper part of the barrel. After turning into char they spontaneously broke into smaller pieces and felt through sparse grate down into the anaerobic (oxygen-free) zone and cool down without changing into the ash.. (Picture 2, Picture 3). This was my char drum version 1.0. I am planning to use 55 gallon drum this year. It will have one improvement - the grate and air holes will be located in upper third of the drum, so the fire zone will be smaller, while the char-zone larger.. I add the charcoal into my large composting trench and mix it with organic stuff. I do not crush the char at all. I leave the compost with biochar up to 1,5 year in the trench before using it. The biochar content in the compost is not high, some 3-5%..

Jan, this seems like a neat way to make charcoal.
I can imagine putting a quenching liquid in the bottom of the barrel or can.

Do you build a small fire on the grate and add to it as the coals fall through, or do you light a batch and let it do its thing?

What size are the openings of the grate?

biochar is new to me, but I want to give it a try.  I will admit I didn't read every post, but it looked like everyone has something they bought or made to make the biochar in.  I watched this guy on You tube make it in a cone shaped pit he dug in the ground.  It seemed like a 0$ cost way to make biochar.  Anyone tried this? Or know why I shouldn't?

Jen Fulkerson wrote:biochar is new to me, but I want to give it a try.  I will admit I didn't read every post, but it looked like everyone has something they bought or made to make the biochar in.  I watched this guy on You tube make it in a cone shaped pit he dug in the ground.  It seemed like a 0$ cost way to make biochar.  Anyone tried this? Or know why I shouldn't?

There is nothing wrong with doing it that way.  Every method has pluses and minuses.  I have tried just about every way possible, and I still don't have a favorite.  At my new land, I don't have water yet, so I don't have a good way of quenching.  The retort or TLUD is better in that situation.  In a pit or a trench, if you have a lot of material and a way to quench, you can make much larger amounts than with any other way.  Like many things circumstances and personal preference will dictate the best method to a large degree.

Chris Kott wrote:
One of my favourite setups is the kon-tiki.

-CK

Where would a person get a kiln like that?  I do something similar with my fire-pit, but having a big steel kiln would be amazingly efficient.

Does someone make these commercially?

Marco Banks wrote:

Chris Kott wrote:
One of my favourite setups is the kon-tiki.

-CK

Where would a person get a kiln like that?  I do something similar with my fire-pit, but having a big steel kiln would be amazingly efficient.

Does someone make these commercially?

You can buy them here: Kon Tiki kiln but they are extremely expensive.  You can have any metal shop near you make one for really cheap.  I asked a guy here and I forget what he quoted me, but it wasn't much.

I took a couple pictures of one of my TLUDs today, with a typical load of the type of material I use from my cleanup. I have a lot of snow, so I tipped it on its side to show the air slits. The slits in this not the best way, btw. The way I cut them, dirty falls into the barrel when you cover the holes to stop the burn. If you make the top part of the slit come out from the barrel, you can cover them and have less dirt go in.