Does anyone have a simple test for charcoal to confirm if its conversion is complete? I am starting to make charcoal from dried hardwood chips and most of the first batch looks and feels right but some looks good but feels a bit heavy. Not being overly familiar with handling this product I am wondering if there is a way to sort out or test for incomplete charring.
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Wyatt - About the only reliable method I have found is to hand sort it, and break the pieces by hand.
By this, I don’t mean hand crush it. I mean just go through it, take the bigger pieces, and see if you can break them, and look at the inside.
After you have done that, you can safely run them through your crusher and burn them.
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Hi Wyatt , chips or shreds can be a problem unless you can rotate it while its burning and that helps to carbonise it a lot better , a long pitch fork even turning it by hand once the top layers started to go white and dusty will help ,
I have a garden shredder that I put my charcoal through to size it and if it comes across any that’s not cooked well enough it stops the motor, or slows it down for a few seconds , luckily it doesn’t happen that often ,
Dave
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There is some guy on youtube that says hetastes every batch. It shuldnt have a taste. Might work for makeing charcoal out of bigger wood, chips are a problem.
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Good charcoal washes easily from hands without staining, ie. no tar.
Another not so simple test: Vermicomposting worms like eating the good stuff, but not the tarry stuff.
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Wood chips can be tough to make charcoal with unless of course you can use d100f’s suggestions. If you are usind a big barrel and can’t access it, then a pipe going up through the middle for the chips in the middle of the barrel.
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Hi Wyatt, I do not know if you are using the direct or indirect method of making the chips into charcoal. If it is the direct method, you will know the wood is charred when the yellow flames no longer appear. The yellow color is an indicator of tars being burned off. Stir the charcoal around a little and if there is yellow flame, you still need to cook the wood a little bit more. Charcoal burns with a blue flame.
When using the indirect method of making charcoal you cannot see whether the off gas is yellow or not. One reason I do not use this method of making charcoal. My guess is the gasses from the kiln will cease to blow out as smoke or shoot out a yellow flame. With the tars burned off and no oxygen present in the kiln, the flames should die out indicating all the wood is charred.
Gary in PA
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Thanks for all the replies. I am using the indirect method, repurposed cold water bladder tank, about 50 litres of volume, cut off at the bottom with a loose tin bottom added to keep the wood chips from falling out when it is upside down. Hardwood chips are from a large sawmill chipper and are a variety of sizes and very sun dried. 45 gallon steel barrel , topless with air holes punched in the flat bottom on the very outer edge and propped on three boards. Fill the old water tank upside down, put on the tin bottom, flip it over and lower it into the barrel using its chain handle. Put 6 or 7 dry softwood slabs vertical between the tanks, bit of scrap and kindling on top and light. Spacer bars on top of the barrel and add a 2/3 barrel chimney on top, walk away and return next day to empty finished cool charcoal. I have made three batches so far, 2 and a half pails of raw chips turned into 1 packed pail of finished charcoal per batch, not sure if it needs to be re sized to use. Now I have to build a gasifier.
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The best way, not a joke, is putting some of your charcoal in a old microwave…
If no smoke appears in 3 to 5 minutes, then your charcoal is ok…
My wife is still angry after my first test with her microwave… the charcoal was not ok…
The kitchen smelled for a week…
a new microwave …
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My wife is in bed already but maybe I will see if I can pick up a working charcoal tester at the dump. Small ones regularly get thrown out as bigger ones are bought for cottages and people consolidate households. I looked closely at one batch today piece by piece, mostly pulling out larger thicker ones to see if they would break, crumble etc. Everything is black through and through but a very small percentage are stronger and have a different sound when dropped on metal. This might be due to differences in wood density, at least one looked like a piece of burl but broke nicely.
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Koen, if you would buy her a new microwave, she would probably let you have the new old one that you have used for charcoal testing. Then she would not get mad, unless you would go and use her new one. LOL
Bob
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My brain just kicked in an interesting memory of a home made machine for sorting seeds to eliminate grass/weed seeds from a volume of grain. It used air flow to sort the heavier from the lighter and shunt them to two different containers. This might work for sized charcoal fuel stock if necessary. My next question is, is it necessary?. How much imperfect charcoal can I have in a batch without causing problems with my engine? After hand sorting one batch I estimate that I have under 2 percent questionable charcoal which is black through but heavier and more solid than the rest. The other 98+ percent tinkles like broken glass and is lighter and crushes easily. I am inclined to use it as is.
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l think you will be just fine as it is. If you can brake it by hand it is ok. Some tars produced in the gasifier will just burn as the char is gasifiing, some left over will be absorbed in colder lairs of charcoal to be burnt later, some will be extracted in the filter and the bit that is left shuldnt pose a problem.
The way l sort the charcoal is first extract the big brown peaces of wood by hand thaun start dumping it in a chusher. If there comes a hard pice of the crusher rotor it stops it. l put it out. Anything soft enough to be crushed goes in the gasifier.
Had a few tarry batches but my hoses and engines paper filter is still clean.
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The biggest chip I am starting with raw wouldn’t be larger than a pack of paper matches in overall volume. I did pick out some brownish ones in the finished batch but I think it was either a trick of my eye or a bit of rust rubbed onto the charcoal. Just picked up a very compact electric hand vac at the dump to start the process until I can get something 12 volt.
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I spread the finished charcoal out on a hardware cloth (1/8") frame to inspect it, and move it all around with a hand brush (the one that comes attached to a dustpan). Any questionable wood pieces that get picked out end up as fuel for my TLUD charcoal making cookstove, mixed with regular wood. The wood chips that I get for free at the City Park are hard to work with and mixed with lots of green wet leaves, so I put them in one of three compost heaps which get turned with a front-end loader. Later, when I screen the compost, I sometimes find larger pieces of chips, or pieces of heavy branches that didn’t compost. These get picked out, dried, and put in the charcoal retort. The charcoal fines get mixed into these compost piles, too, and turns the compost darker.
Outdoor burning is now banned in this area, and I have been screening a four foot high pile of charcoal that I made earlier this Spring. I have noticed rust colored pieces of charcoal caused by nails rusting. It seems to be good finished charcoal, so it goes into the grinder, then back to the screen where it lays for a day under the hot Texas sun. Then into a sealed 55 gallon drum. The nails are picked out and dropped into evaporated milk cans, and the cans are flattened, and hauled to the steel recycling place.
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Some of my high temp charcoal is electrically conductive. If I series two 12v batteries and grip this charcoal with jumper cables I can draw a carbon arc. Also if I put this variety of high temp high grade charcoal in the microwave it starts arcing within a few seconds.
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Indeed, must be careful not to put it to close to the metal surface of the microwave…
i have a glas turning table and a ceramic pot to put it in…
Next month i will have a high temperature oven to do testing… can’t wait…
http://www.abb-furnace.com/furnaces/electric-furnace.html
This for testing and upgrading charcoal…
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Ironically, all you probably have to do is to change the charcoal filter in the microwave. 
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For testing the quality of charcoal, why not just place it in a small stove, light it at the bottom and see how much smoke is created. Well made charcoal will give off minimal smoke and no yellow flame. The stove can be a can, say 3" in diameter and 10" tall with air inlets spaced around the bottom, Fill with charcoal, light the charcoal and see how it burns. A
Gary in PA
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I had thought that a flare test might be in order but I don’t want to test very much volume, I am willing to pick out and identify by hand the small percentage of suspect pieces, now I need to decide if they are a problem and how high a percentage I could have mixed in before having engine mechanical issues.
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