[Terrapreta] Making Charcoal in a Drum

[David Yarrow]

"stopping before the ash stage" and "stop before you reduce it to ash" is a 
bit fuzzy.

more precise thinking is to choke the fire down and reduce the burning to a 
smolder, then sustain it until al or most of the material is consumed.  the 
idea isn't to stop the burn, but to slow it down and control it to a steady 
reducing fire.  it is a bit of an art to know how much air to let in and how 
to regulate that so the solder doesn't go out.  it seems the ancient 
charcoalers just heaped their burns with soil, and the air sucked in through 
the loose dirt was sufficient to regulate the smolder.

if you just take an open fire and stop it, you wind up with little 
charcoal -- mostly on the surfaces of the wood.  more is reduced to ash or 
left as unburned wood.  which is fine, but not very efficient if you want to 
sequester as much carbon as possible as char.  and less desirable if you 
want to minimize the release of carbon as nasty greenhouse oxides.

for a green & peaceful planet,
David Yarrow
44 Gilligan Rd, E Greenbush, NY 12061
www.championtrees.org
www.OnondagaLakePeaceFestival.org
www.farmandfood.org
----- Original Message ----- 
From: "William Carr" <Jkirk3279 at qtm.net>
To: <Terrapreta at bioenergylists.org>
Sent: Tuesday, January 29, 2008 5:46 AM
Subject: Re: [Terrapreta] Making Charcoal in a Drum

> Otherwise, char is char.   Burn biomass to the point that it's
> inedible by soil bacteria, stop before you reduce it to ash, bury it,
> and you've sequestered CO2 for thousands of years.
>
> The point here is stopping before the ash stage.   Otherwise the
> Carbon just ends up in the atmosphere again.