OK, I have a question for you pyrolysis experts:
My retort charcoal rings or makes clinking sounds when it is shaken around. Charcoal made in a direct burn kiln does not have this clinking characteristic. What causes this difference?
I was noticing the same thing yesterday, and came to the conclusion the pores in the char in the direct burn kiln could be filled with fine particles of ash, whereas the pores in the retort charcoal are open.
After I ran them through the charcoal grinder, it all looked about the same.
Somewhere I got the idea that it was from high temperature, but a friend said he thought the char in his direct burn barrel kiln would be hotter than my indirect retort. Open pores vs. ash filled seems plausible.
I noticed that tooâŚI think ray is right, but Iâm not a pyrolysis expert.
I have noticed that difference in sound too, and I also feel like there is a difference in hardness. The stuff made in a sealed retort seems to have the same density, but it stays in much larger pieces, and does not crumble as readily. The stuff done in an open burn almost seems puffed - could there be a pressure component to it?
Your retort is looking good - how many runs have you done with it? I am curious if you use anything beyond a steel band to seal your lid, and if you have any trouble with smoke leaking out around the edges? How much surface area do you have in the holes in the chimney for the wood gas to exit? I feel like my retorts have always leaked irritating smoke around the rim- but maybe I just didnt have enough exit holes and was building up too much pressure.
Thatâs a good thought. Seems like it could hardly build much pressure though if itâs vented well. Maybe it just gets hotter? I would like to try to make some hardwood char to sell to bbq-ers at the lake. Been wondering what would be the best way. They like it to be in big pieces.
Carl,
Good call. Yes, this retort leaks a lot around the lid and some gas also sneaks out around both ends of the chimney pipe through the vermiculite insulation. There are 12 holes (1/4") in the bottom of the chimney pipe. Six on each side at 5:00 and 7:00 looking into the pipe. My larger 55 gallon retort has the same arrangement, but seals tighter. The large one roars since it produces more gas under greater pressure. This small one has a gentler burn but is still hot enough to make good charcoal. Iâm interested to hear if others have experimented with more or larger holes.
Billy,
Most grilling charcoal is made by shutting down/snuffing before it completely off-gases. This gives a heavier more hydrocarbon filled charcoal. I have a professional griller who likes my lighter pure carbon charcoal because it does NOT add wood flavor. It allows him to control the exact flavor with marinades.
Carl,
Only three runs with this one, and six with the 55 gallon. So far the barrels are holding up well. I originally used regular stove pipe that only lasted for 4 burns. The SS chimney liner (free liner trimmings from a local stove shop) seems unaffected by the high temps (1600F) on the glowing stove pipe.
I make charcoal in 55 gal. drums here. The barbecue and meat smoking people seem to like it. It doesnât alter their preferred taste they are trying to achieve. It does burn a lot hotter than the bagged stuff for sale. Best charcoal sounds like glass when dropped. They look for that before they buy.
This video is an example of what a nicely made hard wood charcoal sounds. The japanese traditionaly make carbon for mileniums, they pefectioned the system to make what they call WHITE CARBON; it´s mostly from mangrove wood (we are useing old guava trees in their finals), it´s very hard wood and produces something similar. This week we are going to make a batch of bamboo charcoal and i´ll pu some guaya sticks in it, then I´ll make a video with the sound and post it. This carbon makes no smoke and yhe sound tells you the cuality of he charcoal for cooking. I´ll keep tuned in with this, for me it´s a pasion.
This is another one. Notice there is no smoke in the kiln.
Listen to the sound of charcoal when beeing cut.
This one is long, but is very instructive and makes you really think of charcoal
Abner the video is blocked in our country USA because of the back ground music.
Bob
I have watched that video before, try this link.
Hi,
let me introduce âCharcoal Charlieâ 
I found this video an I really like this retort. Larger and heavier than with an internal flue, but the bigger burn chamber doesnât need an afterburner and the larger heating surface speeds the process up.
Okay. I did the 55 gal drum with a to then a 6" Pipe out the top with vent hole near the bottom. I got too much smoke. So I added a 1/3 of a barrel in top that I attached the top to on top of the barrel held up with square tube. I get significantly less smoke with it. Most of it is drifting out the side but it is burning a lot hotter and faster. But I donât think it is doing as good of job baking the logs I threw in.
Should I be looking at putting a skirt around the gap, making a more permanent way to set the barrel on top, or increase/decrease the air gap (1 side is 1/2" the other is 3/4 because that is what I had)?.
Also since I am now dumping water on it to put it outâŚHow do you dry out the charcoal? Just out in the sun? It just leave it wet?
My favourite way of dousing char is in a 7 gal flour tin with the tight fitting lid. Deprived of oxygen the char is out in minutes, and left utterly dry. I have heard of barrel collapse using 45 gal drums, but it seems this is due to the rubber gasket melting and hermetically sealing. You donât need, or want a perfect seal. Once the char is deprived of sufficient oxygen, it will rapidly fall below the combustion point, being of relatively low mass. So my advice is provide a small vent hole in the container of your choice, and avoid the dryingâŚ
It is like 700-900F according to the HF infrared temp gauge. Iâm not picking up a barrel that hot. Cutting the air off to the barrel like I was doing was taking up to like 12 hours probably due to leaks, it originally didnât take that long.