first char today

Had a salvaged five-gallon terracotta flower pot, filled halfway with sticks and lit the top.  
After 20 minutes or so I had a good fire burning and added two handfuls of sticks.
When the smoke cleared, added two handfuls of sticks.
When the smoke cleared, added sweet gum balls (too many) and it smoked for a long time.
When the smoke cleared, added the last two handfuls of sticks.
When the fire died back, I quenched the fire with about 8 gallons of water.
Top pieces look good, fully charred and crush well.  I'll check the rest tomorrow evening.
I'm guessing I'll net about 2-1/2 gallons of really good maple stick char.
I'll add fresh worm compost tea to the mix tomorrow night.

It took about an hour and I probably burned 10 gallons of maple sticks and 2 gallons of sweet gum balls.
I think my production can double and reduce my time by about 20 minutes for the next burn.
This is my new obsession.  I'm pretty sure it's going to be a good one.

Excellent experiment!

But quenched with 8 gallons of water? I think you washed a ton of fertilizer out the bottom.

I would suggest that next time you add a modest amount of moisture and cap/seal everthing with clay, sand, whatever subsoil you can get to stop combustion. It works.

But there's no absolute right or wrong. Keep going!

You know the terra cotta "saucers" they sell for sitting under pots? If you could get one the same size as the top, a little clay stuck to it's edge and only a little water and drop it on might smother the fire fairly quickly. I'm assuming there's a drainage hole in the bottom, so I'm thinking it wouldn't blow up on you, just significantly reduce the airflow.

Just a thought. Makes me think I should check just how big my biggest pot is??? I admit one big, solid pot I decided to move a plant into, as the pot it was in was breaking. It's not *that* happy in its new home that I couldn't change my mind if I could get the near-by bed rehabbed. First I'll check my stash!

Thank you both for your comments.  I've been obsessing about this for over a week and I figured out how to "try this at home" with $0 input.

If the unveiling goes as well as I think it will, I will invest in some upgrades to improve the process.

Quenching the fire was done a quart at a time until the steam stopped rolling off the char.  

I was looking for proof of concept vs. grade A char with this trial - I just needed to burn something.
 
Because the decision to burn yesterday happened fairly quickly, that meant I didn't have a non-flammable lid for the stopping the burn - I looked.

I'm pretty sure that the pot is history.  I heard several loud pops during the burn.  It was curb salvaged several years ago and I finally put it to good use.

I am probably going to go with the double stock pot TLUD build in the near future.  It fits my neighborhood and storage options better.  

Anybody else tried that one?  Also thought about the wok shaped fire pits as a cheap/easy option.

I'll try to get pictures up tonight with my success or failure.

Your process sounds a lot like mine. I use a half oil drum cut lengthways. Works great, and produces large volumes quickly.

Half Barrel Method

I'm very pleased.  2+ gallons of good char.  Uniform char from top to bottom.  Little or no ash.
I'll be adding the bio and the crushing in the next couple of weeks.  
My pot was weakened but still useable.
And I will get a flame-proof cover before I do this again Friday or Saturday - maybe both.

That is a quarter for reference.

Biochar that has just been burned is not full of nutrients.  You just burned it to send away all of the volatile oils and natural chemicals in it.  You aren't really washing them away.  Quenching the fire is one of the most classic ways to shut off the process so it stays at burned char and doesn't turn to ash.  Most people will crush the char, and then put nutrients into it to inoculate it.  I wouldn't worry about drenching it.  It's just hotels for microbes at that point. No nutrients to wash away. That happens later.
John S
PDX OR

Yes, I was exaggerating a bit. But with an open burn you can't help but create some ash, and that's potassium for your plants -- unless you wash it away.

Good point.  The alkaline ash does provide potassium nutrients and alkalinity.   Especially if, like me, your soil is naturally too acidic and you want to keep that ash to make your soil more alkaline, or closer to neutral.  

When I burn a char, I wait until it is at the time for the most char. Then I spray it with water to stop the fire from burning.  Afterwards, I put it in a bucket with water to make sure it's no longer slowly smoldering.  I pour that water on my plants that could use a little more alkalinity.  Then I crush it. And then inoculate it.

John S
PDX OR

It's true -- fresh char will smoulder quite tenaciously. I usually smother mine in a portable firepit with a tight fitting lid. Just enough water to put out the fire and steam does the rest. Unless I fail to snug up the lid just right ...

I have to be careful since my soil tends toward alkaline. If I rinse the char, I collect the water and put it on plants that don't seem to mind. Like raspberries.

This conversation makes me curious about char that's made in an industrial grade kiln. I assume that means no ash. Where does the potassium go, and what's the pH?