A big win on the biochar front for me

Let me say upfront, I understand that this is only useful for the small portion of people that a) make charcoal for biochar in a retort, and b) have a wood chipper, or access to small wood chips.  This method is probably not as good for those big wood chips the highway crews and tree services generally make, although they still work.  They just don't solve the problem I wanted to solve.

The main time consumer I have when making charcoal isn’t the actual making of it, it’s crushing it to make small enough pieces to be incorporated into my compost, and in turn, my gardens.  The time to make charcoal is largely irrelevant to me.  I load the retort, load the barrel around it, light the fire, and go on to do whatever else needs doing.  The next morning I empty the charcoal out.  Easy peasy.  Actual work time is 15 or 20 minutes.  The problem for me is that I empty the charcoal and store it in large trash cans until I get around to crushing it.  With other pressing issues, that usually doesn’t get done until I’m making a new compost pile, or making a new garden.  Crushing it entails scooping it into chicken food bags, double bagging, and running over it with my vehicle enough times to get it to the point I like.  Empty the crushed charcoal and repeat it quite a number of times to get through a batch of charcoal.  A smarter person than I would start the first bag as soon as the charcoal is done, and as each was crushed, load a new one, and just drive over it during normal trips to and fro.  A week and it would all be crushed, and with no extra driving.  I, on the other hand, am always busy with something else, so it doesn’t get done a little at a time.  That means wasting time running back and forth over it, emptying that bag, doing another one, and so on.  Slow, fuel wasteful, inefficient.

But wait?  What if I didn’t have to crush it?  That would be a huge win.  I tried using sawdust, but it doesn’t char easily because it is too dense in the retort, and too much of it turns to dust and blows away.  Planer shavings are much better.  They char easily and don't need to be crushed.  The problem with those is that I don’t have a ready supply, and they still crush into dust more often than I would like.  Then I stumbled onto the idea of using wood chips.  I’m embarrassed it took me so long to think of frankly.  Most of my biochar is made from scrap lumber that I get free.  It’s normally pieces of 2x2 or 2x4 lumber of various lengths, sometimes 8 feet, often 5 or 6.  I also have lots of tree branches from cutting firewood from dead standing trees.  I started taking the long pieces and running them through my chipper.  Yes!  Perfect sized charcoal pieces, ready to be incorporated into my compost piles.  They are ideal size to be used with no crushing.  They don’t turn to dust while moving them around.  They char perfectly.  It takes me far less time to chip the lumber than it did to crush the charcoal, and it isn’t messy or dusty.  For me, it is pretty much the perfect solution.  Hope this helps someone in the same situation.

LOL, had to add, I looked at my old posts and saw that I first posted about having this idea 8 months ago.  I finally got around to trying it.  That pretty much tells you how things go on my land.

The only efficient way I have found of making charcoal out of leaves, involves mulching with a lawn mower, then lighting it, always covering up lit area with unburnt leaves, until it all appears somewhat burnt. Made a lot of charcoal today, by starting a fire, then smothering it with chainsaw mulch, and other debris and bark from a recently downed tree. Always have to extinguish fire at right time, which is the art.

Trace Oswald wrote:LOL, had to add, I looked at my old posts and saw that I first posted about having this idea 8 months ago.  I finally got around to trying it.  That pretty much tells you how things go on my land.

I hear you Trace - there are projects I'd like to have done 5 years ago, but there are always higher priorities.

However:
1. Chipping - yes, I threatened with Hubby chipping some of the packing skid material for exactly this purpose, but he was really anxious that he'd miss a nail fragment. I can't say I blamed him.
2. A neighbor has a mill that makes fine and coarse sawdust. Yes, particularly the fine stuff is pretty dusty, but any port in the storm. We're using warming tray bins in our wood stove, so they're not too deep which helps with the compaction part, however, to help more, I save dry Doug Fir cones and put them in layers alternating with the sawdust. Hubby has eggs and meat chickens that he sells which often results in dead birds. Any that have enough meat to be useful gets turned into crab bait, but being able to add that fine charcoal along with some sawdust to the paper bag I compost the birds in, is really great at keeping down the smell. By the time it's turned into compost, the fine charcoal is just more carbon in the compost and not a dust hazard.
3. When I first started making biochar, I used hardwood bits that were generally about 1"x1" +/- a half inch. Yes, they were too big and the wrong shape and a total nuisance to break up.
4. We end up putting bones from roasting chicken or other animals in the wood stove so they don't attract vermin. Those need a certain amount of breaking up, but it's pretty easy and I figure the calcium and phosphorous they represent are worth keeping.

I'm glad you've found something that works for you - we may end up going there, but at least here are some more things people can consider. If you end up with a bunch of sawdust, you might consider doing the layer thing in the char, or just layering sawdust, char, and whatever else you're building your compost out of.

Finding new ways to manage raw char is magnificent and worthy. Well done!

In my part of the world, I use the natural freeze/thaw cycle to my advantage. Char saturated with moisture will expand and shatter over time. This is the same system that grinds mounains into plains. It's not fast, but my char system is pretty lazy, so I assume (based on experience) that it will work out over time.

So glad it worked for you.

Some of my best ideas brewed in my mind for years before the "light bulb" moment of exactly how I could make it work suddenly materialized.

Douglas Alpenstock wrote:Finding new ways to manage raw char is magnificent and worthy. Well done!

In my part of the world, I use the natural freeze/thaw cycle to my advantage. Char saturated with moisture will expand and shatter over time. This is the same system that grinds mounains into plains. It's not fast, but my char system is pretty lazy, so I assume (based on experience) that it will work out over time.

I have done that in the past as well.  Most  times it doesn't matter.  My concern is that I mix a big chunk of charcoal into my compost, it will be a nutrient deficit for some extended period of time that it takes to inoculate a big piece.  I have no idea if that is accurate or not.  Small pieces of charcoal are also much easier to scoop up.  In the long term, using larger chunks probably doesn't matter a lot.

Michelle Heath wrote:

So glad it worked for you.

Some of my best ideas brewed in my mind for years before the "light bulb" moment of exactly how I could make it work suddenly materialized.

Same here.  I need a notebook or something though.  Sometimes I "discover" the same idea years apart because I forget all about them

My feed material for making biochar is branch wood, similar to what you are running through your chipper. I don't chip it, I just use an open trench system. It breaks down by itself to pieces 1cm or smaller, without any special need to do any crushing. Burning bigger stuff, like 2"x4", always leaves big chunks that need some work.

Have you tried burning those same branches without chipping?

Hi Mike,

Could you say what size branches you use? Do you try to get them a uniform size? I'm about to make my first biochar in a couple weeks and don't have a lot of options for materials. But I do have branches, lots of branches.

Thanks!

Mine are everything from pencil thick to about 2", sometimes up to about 3" but they tend to char unevenly. 3" and up gets chopped to length and chucked in the firewood pile.

I burn the whole branch in long lengths, over a pit dug in the ground. Keep feeding it material over an hour or so. As the wood burns the embers drop into the pit, where they are protected from burning away by the flame cap above.

Then I either quench by filling the hole with water, or I shovel the hot embers out and dump them into a metal water trough. If I do the latter, I can keep on adding more fuel to the fire without having to start again from scratch.

Oh Mike, thanks so much for that reply! Very helpful!

I'll be burning in a couple of weeks, will post about how it goes.

I love hearing about people finding a new way to be successful with something.  Here in the PNWet, we grow trees like crazy. Many people consider trees to be a nuisance that you have to pay someone to chop and haul away. As such, wood chips are very easy to get.  It makes sense that this works in your retort.  I don't use a retort, but the more examples of successes that we post here, the larger the number of people who will find a way to make it work at their place. I know there are probably 5 lurkers for every person who posts.  Biochar was one of those things that I figured I had to do someday, until I saw a post like yours, Trace, and then I realized that I could do it.

John S
PDX OR

Just a couple pictures of the latest batch.  I couldn't be happier with the way it turned out.  The small size helps the chips char perfectly.  They don't stain your hands and they make that lovely breaking-glass sound that all charcoal makers love :)

First pick shows the size and kind of chips my chipper makes.  Second is the finished product.