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charcoal how to evaluate end product and to grind it?  RSS feed

 
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We've made charcoal and it is looking pretty good. But how do I really know that what we produced is the right stuff? There was a microscope mentioned in another thread - how do I really know without that expensive microscope that we did the right thing?
Second it was mentioned that pulverised is better. Best and easiest way to grind it up?
 
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Hi Angelika. That's hard. I could be wrong, but I think it's easiest to evaluate with a microscope, otherwise why go to the trouble, right?

I have some thoughts. You could test simple toxicity by growing an assortment of plants in soil heavily amended with innoculated ground charcoal, that is, biochar. I have heard  that there can be microbial drawdown issues if you don't innoculate with compost or compost extract, sort of analogous to the nitrogen drawdown you sometimes see with too many wood chips mixed in to the soil.

You could also burn it. I haven't done this, but it would stand to reason that if you've opened the pores in your charcoal properly, there's nothing left to burn. If there are high levels volatile material still in it, the charcoal should catch fire really easily, shouldn't it?

The other way I would approach the issue without a microscope would be through procedure. If you were to "overbuild," as it were, your retort, and give it an excess of heat while making sure no oxygen could possibly enter your retort, then I think that all you would need to do is have a thermometer, or be able to tell what the temperature of the retort is by the colour it is glowing (if it's metal).

As to grinding, it depends on what scale you are making it. Would a big mortar and pestle do? I would maybe use a burlap sack or other rough material, half-fill with charcoal, and go to town on it with whatever I had, probably a sledgehammer. Or a roller (like for landscaping). It also depends on the size of your material after the burn. I wouldn't try to use a small roller on huge chunks, nor would I use a sledge on briquet-sized bits.

Good luck, in any case. There's always trial and error, but I think keeping an eye to processing temperature is the easiest non-microscope path.

-CK
 
Angelika Maier
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The roller is great. I have to have a think probably there is someone with a microscope I could ask.
 
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In terms of biochar, I have read that making it at 450C is the best way to get the perfect mix.
Too low a temp and the char is filled with organic liquid (hydrocarbon, some with OH (ethanol) some with C00H (ethanoic acid) I am sure that they would be much heavier than just two carbon etha
Basically what this does is make the char inhospitable and when it leaches out, it kills soil life, and is more or less a preservative (think rail road lumber).
It takes a long time to leach out (decade) and even after the pore size structure of the biochar is not right and the chemical structure of the carbon is not right.
I think most of this char also ends up in the atmosphere, also the yield is very high due to all that syngas/etc

If the temperature is too hot, then the pH of the char is too high, and the carbon compound is somewhat toxic, also the pore size is not right. But I think this is the most stable of all char but this has the lowest yield.
 
Angelika Maier
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How to know that you are at 450C?
 
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To do a rudimentary test of charcoal that will give you an idea of how many of the impurities are gone you can hit it with a small rod of any metal or even something like a writing pen. If it sounds out with a "tink" then it is probably mostly free of impurities you don't want in char for your soil.
The "tink" will sound similar to crystal glasses being touched together in a toast.

If you have a magnifying glass you can use that to inspect the end of a chunk, you should see the holes that transport sap (large) and the holes of the structural tubes (small) and they should be clear (nothing blocking them at all).
If in doubt you can lay some of the chunks on something like a baking tray and put them in an oven for an hour at 450 f , this is for already made charcoal. That will let you know through odors coming off (or no odors) if the cook to charcoal was done well enough.

Redhawk
 
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The easiest way I have found to crush it is to put it in a strong bag, like the ones chicken food or dog food come in.  Fill the bag about half full.  Take another bag and pull it down over the open side of the first bag, lay it in your driveway and run over it with your car a few times.  That will crush most of it.  The larger pieces I just throw in with the compost as well.

I don't think anyone is sure about the best temps, the best size, the best material, all those things.  I used to worry about it more, but I decided that the "primitive" people that made terra preta didn't have all those answers either.  They didn't have access to microscopes, or exact temperatures, or any of the things I was worried about, and they managed to make something wonderful.  I'm not saying those things aren't important, just that I think worrying about all of that stuff shouldn't keep you from just doing it.  I'm finding I get far better results now that I've decided to just do things and see what happens, rather than thinking about them to the point I have "analysis paralysis" and then I don't ever do it.  Whoever said "perfect is the enemy of good" nailed it.
 
Chris Kott
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I agree with the whole perfect being the enemy of the good and the analysis paralysis  points. But how long did it take for the traditional knowledge surrounding the making of terra preta to come about? Trial and error can take a long time.

I am not saying to not do anything until you get the process perfect. That doesn't make sense. But I think it makes sense to get as much knowledge as possible without letting the research impede you. I think that is what the sans microscope analysis is about.

And I love both the tink test and the stink test, Redhawk. Sounds like a great practical approach to analysis.

-CK
 
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I didn't even know there was a "right" temperature for making char...  So after pulling my steam pan out of the wood stove, we let it cool outside for half a day.  Then we dump it into a chicken feed bag that is in our basement.  It does "tink" when we knock them together.

Can I assume that I made it correctly if the bag doesn't stink up the basement? Hardly any odor, maybe zero odor...
 
S Bengi
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I would get a InfraRed thermometer (I see some that measure up to 1,000C for $50).
You could also get a probe thermometer and that would probably give you a more accurate internal temperature.

 
Bryant RedHawk
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The ancients, most likely didn't know they were making Terra Preta, most likely they were using the charcoal to loosen the soil for plants to grow better and over time the bacteria moved in to set up house keeping and thrive there.

In areas that are far from "civilization niceties" methods needed to be found that could be used with decent repeatability and conformity, that is where I came up with the "Tink" test.
Smelly charcoal is easy to detect and odors come from non- carbon materials that remain, so that too is an easy test method to determine if your charcoal is "pure enough".

Far to many people do get hung up on things that really don't matter as much as they want them to matter, it seems to me these are folks that lean towards the "nerdy" side of science instead of helping science be practical.

The main concern with making charcoal is to get rid of all the contaminants that reside in wood, we just want the carbon that is in there and so have to use heat to combust all the crud.
In the big picture, if your charcoal has some impurities it will still work once the microorganisms are living in it, it might even work better because of those impurities.
The thing is, get it done and into the soil so your microbiology will improve greatly and thus your soil will improve greatly.
one of the big things bio char does is hold extra water, it works a lot like a sponge, the water is soaked in and as it becomes used, air takes the place of the water.

Redhawk
 
Todd Parr
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Chris Kott wrote:I agree with the whole perfect being the enemy of the good and the analysis paralysis  points. But how long did it take for the traditional knowledge surrounding the making of terra preta to come about? Trial and error can take a long time.

I am not saying to not do anything until you get the process perfect. That doesn't make sense. But I think it makes sense to get as much knowledge as possible without letting the research impede you. I think that is what the sans microscope analysis is about.

And I love both the tink test and the stink test, Redhawk. Sounds like a great practical approach to analysis.

-CK



Several points come to mind.  There is no telling how long it took for traditional knowledge to come about.  There is also no telling if the way they made charcoal was the "best" way.  We have no idea. 

I'm also not at all against researching an area before beginning.  I do it myself.  Biochar is an area that you can research for hours and have no more answers than when you started, so I decided to just make it and see what happened.  For every "expert" that says high temp biochar is best, you will find one that says low temp is best.  Different temps are said to be "best" depending on the matter you started with.  Take this for instance: "1.08 What temperature range is considered "low temperature" in the context of biochar?
The theoretical low end of the range approaches 120 deg C, the lowest temperature at which wood will char, (Reference) thus the temperature at the pyrolysis front.  A more practical low end is to use the piloted ignition temperature of wood, typically 350 deg C. (Reference) The theoretical high end, between biochar and more traditional charcoal, depends on the process and feedstock used, but is seldom indicated in excess of 600 deg C. This temperature range is more relevant to woody charcoal than to charcoal made from bamboo, or other high cellulose fuels.  Woody charcoal has an interior layer of bio-oil condensates that microbes consume and is equal to glucose in its effect on microbial growth (Christoph Steiner, Energy with Agricultural Carbon Utilization (EACU) Symposium, June, 2004) High temperature char loses this layer and consequently may not promote soil fertility as well. (Source)" taken from http://biochar.pbworks.com/w/page/9748043/FrontPage ;

Apparently, lower temp charcoal leaves condensates that microbes consume and grow very well from.  Higher temps remove those condensates and so do not promote the same soil fertility.  Some people think that same low temp process leaves condensates that are harmful, and using higher temps removes those and so opens more interior passages for the different microbes to live in.  So, if I'm from the first school of thought with regards to this one small point, I get out my microscope and I see the tiny passages in the charcoal are clogged with condensates and I think "Yay, look at the beautiful microbe food!", and if I am from the second school of thought, I think "Oh shit, I didn't get the charcoal hot enough to clear out those nasty condensates".

Maybe at some point in the future there will be definitive answers to all these questions, and the conditions will be affordable and easy to achieve for the DIYer, but for now, my take on it is to make charcoal, add it to the compost heap, and then the garden, and see what kind of results I get.  My results so far haven't been definitive, but I'm hopeful that biochar helps and that I'm not wasting my time doing it.  If I am, that's okay, because making charcoal is fun.

Next we can try to figure out the correct ratio to use.  Researching that is another rabbit hole...

For the record, I am happiest with my charcoal when it makes that glass breaking sound that Redhawk was talking about. 
 
Todd Parr
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Bryant RedHawk wrote:The ancients, most likely didn't know they were making Terra Preta, most likely they were using the charcoal to loosen the soil for plants to grow better and over time the bacteria moved in to set up house keeping and thrive there.

In areas that are far from "civilization niceties" methods needed to be found that could be used with decent repeatability and conformity, that is where I came up with the "Tink" test.
Smelly charcoal is easy to detect and odors come from non- carbon materials that remain, so that too is an easy test method to determine if your charcoal is "pure enough".

Far to many people do get hung up on things that really don't matter as much as they want them to matter, it seems to me these are folks that lean towards the "nerdy" side of science instead of helping science be practical.

The main concern with making charcoal is to get rid of all the contaminants that reside in wood, we just want the carbon that is in there and so have to use heat to combust all the crud.
In the big picture, if your charcoal has some impurities it will still work once the microorganisms are living in it, it might even work better because of those impurities.
The thing is, get it done and into the soil so your microbiology will improve greatly and thus your soil will improve greatly.
one of the big things bio char does is hold extra water, it works a lot like a sponge, the water is soaked in and as it becomes used, air takes the place of the water.

Redhawk



Redhawk, we were posting at the same time.  Great post.
 
Chris Kott
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Didn't you hear, Kola Redhawk? It's cool to be nerdy nowadays!

But yeah, you're right. I think that your observation was the whole point of the thread, if I'm not mistaken.

I didn't think of uncombusted volatile organic compounds as having a smell. Seems obvious now that you mention it.

I figured the Ancients didn't know all of what they were doing, but I figured that they probably did have batches of charcoal that may have killed what they applied it to right off, but then got more stable over time. And they probably noticed that the charcoal that didn't smell also didn't have as adverse an effect initially on the soil, and so they probably used that. I have no reason to think that they did this, but they could have also started mixing some in with their humanure (correct me if I'm wrong, but theirs was the only manure available, as they didn't have domestic livestock, right?) and noticed that after sitting for a bit, the charcoal manure mix didn't kill much of anything at all.

The above is just speculation on how it could have happened through a process of trial and error. Redhawk, do you know of any ancient "how-tos" on this subject? What exactly is known about the history of Terra Preta? Sorry if this is a little off-topic, but history on ancestral methods often yields low-tech solutions that are, by their very nature, sustainable.

-CK
 
Bryant RedHawk
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hau Chris, In all primitive? cultures there are animals that run around leaving piles of poop, most likely the South American Natives did just like my people and collected those piles of poop when they came across them.
I seriously doubt that they bothered to compost manures on purpose, it probably came from throwing all poop in the heaps of leaves and other stuff once they had observed that plants grew better near those refuse heaps.
The ancients were practical peoples, they did more observation in a day than most current humans do in a month (my opinion only but driven from listening to the stories of the grandmothers).

I can use myself and my wife as an example, many times we will be together and I will spot more going on in the landscape than she will, but she too will see many things going on that I miss because I was looking in a different direction at the time.

Redhawk
 
Chris Kott
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I was referring to the (Aztec? ) people that built chinampas in what is now Mexico. I will try to find the source material, but in all likelihood it is somewhere on this site already.

It was years ago that I read this, when I was reading up on chinampas and the methods of land-shaping and hydrological control that the people of that area and time used. I think it stood out because it was one of the only examples on the continent of a sustained practice of using human manure to fertilise human agriculture. To be fair, chinampas essentially relied on the dredging of the water in which they sat, in which fish also thrived and were trapped (in wiers, I think), so the fish manure would have been present in the water and dredgings.

And yeah, it looks like we were all posting at the same time. Great posts, all.

-CK
 
Bryant RedHawk
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hau Chris, I do not put the Aztec, Mayan or Incan cultures in the same group of peoples I was talking about. These were civilizations that rivaled the Egyptian and Roman Empires, very advanced, with scientist working within their cultures.
 
Chris Kott
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Yes, I do get the distinction. I didn't realise it was important for the context to make one. Sorry, my bad.

I figured the ones we don't hear about or have anything left of might have been equally advanced, but because their advancement left nothing graven in stone (literally), we don't have anything left of them and their knowledge but what survived through oral traditions.

But weren't they some of the cultures responsible for using Terra Preta?

-CK
 
Bryant RedHawk
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There is no wrong when talking about terra preta as far as I am concerned.
What we do know about it can be termed supposition for the most part.
It has been found in the Amazon Valley, the southern end of Mexico, down around Peru, and in Argentina, that I am aware of.
It has been determined by carbon dating of the carbon that these finds were laid down some where around 1,000 to 1,500 years ago so that is a pretty broad time span over the whole known area.
I would think that it was spread by traders sharing knowledge they had directly or telling of what others were doing because they had seen it being done.
However, since we don't have "go back TV" or a time machine, we don't really have any way of knowing, all we can do is guess by the evidence we find.

What I think is important about it is that we did find it, mimicked what was found and through experimentation discovered that it works to hold water for draught times as well as improving the soil biology through increased numbers of bacteria and fungi.
Of course what I think important might not be a shared view with anyone else.

Any time I get into a discussion about ancient history, I remember the opening scenes of the "Buck Rogers in the 21st century" TV show where the 20th century Buck is shown a Hair Dryer by the "historian" who calls it a ray-gun.

Redhawk
 
Chris Kott
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Very cool. I have got to look into the historical/archaeological part of this. Not that it matters for making and using it, but I wonder where the oldest Terra Preta is.

Angelika, have you made any yet? Would you mind sharing the method you're using? I have only made charcoal in barbeque-sized batches, where I put an old roaster full of branch lengths and tightly lidded and sealed with clay, with a one-way valve I scrounged to release the escaping wood gas and direct it down to the flames. As it turns out, I must have done fairly well, as it tinked when I shifted it, and there was barely any smell at all.

-CK
 
Angelika Maier
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The trouble is my husband does it, but he does not post in forums. I think his results are pretty good but his method ... it's him who likes playing with fire (our garden is full of neat woodpiles), in reality I don't really know what he is doing, but the result looks pretty good. He simply makes is in a drum, nothing changed with that drum. I like the method with the chook food sacks and the car - simple!
 
Bryant RedHawk
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hau Angelika,  Sounds like you have a good man there. No need to change anything, it is better to do the work rather than wait to have that "just right equipment". I guarantee you that the ancients didn't bother to make retorts or TLUD's for the purpose of making char to use in soils. They most likely just piled up wood and burned it down (might have even been left-overs from a ceremonial bon fire).  I have a 400 sq. ft. area that I put fresh charcoal in as a "control" for my biochar experiments, it has been installed for a year now and that soil is visibly getting better.

Redhawk
 
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