Steve Welch

Our end goal was always soil improvement.  We use a much smaller, less sophosticated "exeter retort" type system. The outside drum is a 55 gallon drum with a clamp on removable lid with a 40 gallon drum with a tight fitting lid for a retort.  The 55 gallon drum has a series of 1" holes drilled injseries everr 5 inches staggered along the lower 15" with an 60" tall 8" diamter stack in the center of the removable top. The retort has holes drill in the bottom so that the pyrolosis gases add to the burn.  We have three os these set up and can burn two setrs each day alowwing them to cool completely before we empty them and reload.  

We are basically lazy biochar makers,  We let mother nature dry the ingredients, pine to burn, hardwoods in the retort (we used pine in the retort but the yeild was much lower).  We only use dried wood, cut in the summer or fall and biocharred the following season.  We don't pit burn and quench because we lose too much and the quench makes it very difficult to reduce the charcoal in to a semi fine grain. this we do in a cxement mixed with small stones as a ball mill.

We charge our charcoal (10gal) in 55 gallon drums with water 5(5gal), urine(5gal), essential elements and humic an fukvic acids additives.  We stir it every couple of days and deem it ready when the charcoal is sinking rather than floating.  Before we spread it we add equal amounts of sawdust and let it soak with the biochar for about a week.

The stuff works miracles and the only problem is getting it spread in the beds,  We have to rake it out to spread it evenly.

This site has been incredibly helpful in our journey to permaculture.  We would like to thank you all for your sage advice.

A little background,  We live in northern lower Michigan in zone 4b. The soil here is sand with occasional pockets of clay like soils.
When we started our gardens they were great for one year and then nothing.  We tried hay bale gardens, massive topsoil gardens but nothing worked for more than a year.  This led us to you, to hegel kulture, biochar and, most recently and importantly, rocket mass heater technology.

What we realized is that the sandy soil retained absolutely nothing.   We decided that we needed a new approach.  We were clearing old. previous lumbered areass with a hodgepodge of mixed trees for future pastures.  A few hardwoods, maples and oaks, with pines. wild cherries, poplars and aspens. We decided to try a combination of hegel kulture with biochar.  We began by making beds with the poplars and aspens as a base, covered by a layer of reclaimed top soil (it wasn't very thick) then a thin layer of precharged biochar covered with an equal mix of fresh top soil and composted cow manure.

Originally, all of the hard woods were set aside, large trees for the lumber mill, large limbs for the fireplaces and woodstoves and the small limbs (<2.5") and tops cut up and dried for the biochar retort.  The dried pine was cut up, split and packed around the outside edge of the retort which was filled with the smaller hardwood pieces.  We used the pine cones to start the fire around the retort.

The resultiung lump charcoal is then pulverized in a electric cement mixed with medium sized stones. It comes out as a medium fine powder.  This is then placed in a drum with water, urine, essentisl elements and humic and fulvic acids.  In the beginning the charcoal all floats but as it becomes primed it starts to sink. Tis concoction is stirred every few days and when it is ready then we add the sawdust and, if necessary, a little more water.  The biggest problem is spreading it on a bed.  We strive for a 10-15% ratio to the top soil and composted manure we will be adding. It is difficult to spread uniformly so we end up raking it out as evenly as we can.

There are porbably some aspects that could be improved but the results so far have been amazing.  Our crop yeilds have grealty increased and there is much greater consistency year to year with only adding composted manure every year.

With the discovery of rocket mass heater technology we are having to rethink how we harvest and use our wood.  We are just starting our first RMH in what is to become our recration/library/exercise room in the very old original shack and garage.  As this project progresses we will be coming back to this community for much needed advice.

John,  We have abandonned open burning  except for the large cleared trees that aren't good for lumber and end up as hugel kulture garden bed bases.  Our experience with open burn was frustrating because to get it right took a lot of attention.  We learned that the best open burns were with stock that was all about the same size. And, for reasons I haven't figured out, the best burns are from the top down, not from the bottom up.

Today we use 55 gallon drums with 8 inch dirameter, 5 foot long chimneys.  Inside the barrels we use 35-40 gallon drums as retorts with tight fitting lids and holes in the bottoms which allows the off gassing compounds to contribute to the heat of the burn.  Like a good RMH, the exhaust is clear and clean - absolutely no smoke once it gets going.

In a couple of weeks when we get back to the farm I will  post some pictures that will, hopefully, paint a clearter picture.

Douglas,

I am envious of your strongarm approach to pulverizing your charcoal and fascintated that you prefer to do it when it is still wet.  Our experience, when open burning and quenching, was that the charcoal was very difficult to reduce when it was wet.  Mostly because the burn was rarely thorough enough to turn all of the wood to charcoal. We ussually opted for waiting until it dried out.  What's your secret?

Great suggestions.  When I get a block of time I will relate the whole saga with the stages we went through to end up with our current process.  When we do our nexr run I will try to take enough pictures to show what we do at each stage.

I would be happy to go through our whole biochar process from beginning to end if you think it might help others to do it.

I guess the question is "how detail;ed do I need to be"?  Wouldn't it just be a regurgitation of earlier posts?  There are, afterall, really only two methods of charcoal making and they have both been around for forever.

Thanks for your kind words. I certainly hope that it helps others and encourages them to try.  We live in Northern lower Michigan and the soil here is a thin layer of topsoil over sand with some gravel and rocks - you get one year of mediocre yields and then nothing. We scraped off the top soil and built raised beds with a hegel kulture base (using the cleared "junk" trees) topped by the reclaimed top soil augmented with precharged biochar and it has increase our yields many times over.  Well worth all the work.

Gentlemen, I haver used two machines to make powdered charcoal. The first was a leaf shredder with a 5 hp gas motor.  Does a good job but makes a hugh cloud of charcoal dust that seems to get it to everythiung. The second one is a small electric powered cement mixer with a dozen fist size stones thrown in when I run it.  This has worked extremely well with a bucket place over the opoening.  It does a decent job of keeping the dust in the mixer.  In both cases we used a 1/4" hardware cloth screen to seperate out the not thoroughly burned chunks.  The pulverized charcaol then goers into 55 gal drums for charging.

If the charcoal chunks coming out of the retort seem too big, we first run it through the shredder for a short run to reduce the size and then put into the mixer.

Hope this helps.

Hi, Is your offer still available? I would happily help dig for some. Could not figure out how to PM you as I am a newbie on this site. Please PM me, if possible. I commute between Ann Arbor and Lewiston. thanks, Steve