Q&A for How to Make Charcoal

All fires produce gases which can be dangerous to inhale, but charcoal burns more cleanly than wood as it is mostly carbon and produces little smoke.

Yes, dig a conical pit. Start a good fire in it with bushy material. Then layer your wood into the flame, keeping a good flame going till the pit is full of charcoal. The flame provides the heat, burns the smoke, and stops air getting at the charcoal. At the end, add only smaller wood that chars more quickly, and after the last small wood wait for the flaming to stop then either quench thoroughly with water or cover with clayey soil and let cool.

This would depend on the size of the drum. Cured wood loses approximately 75% of the weight when turned to charcoal. This is approximate because there is a variable amount of water content in the wood, the density of the wood being used, and how completely the wood has been converted to char.

Theoretically yes; however, the means to collect the gas and funnel it down into the fire would be tedious.

The melting temperature of steel is well over 2000 F - making charcoal doesn't get anywhere near that, so you should be fine.

Yes, because you want to contain the heat generated by the fire to "cook" the contained wood.

No, the charcoal should not be used to filter water.

Yes, however be sure that the gas is not hot enough to melt the drum and ignite the wood inside.

As long as the wood is dry and is not colored mulch. For best results, use Cowboy brand wood smoking chips because they are dried and cured.

Make sure it's completely dry, but it will still create some smoke.

Yes, the idea is to burn off the water, oils, and other materials in the "green" wood until just charcoal is left behind; this can be done in multiple stages, but every time it cools down you lose a tremendous amount of energy reheating everything.

Yes. As it is carbon, it simply reduces to its base elements, which go back into the ground.

The holes should be put into the base (bottom) of the second drum.

Provided you can heat the wood past the combustion point (300 C/572 F) inside a sealed container, yes. Note the long cook time would consume a lot of fuel in a rocket stove.

You could, but you would want to do it on a smaller scale, like in a cookie tin over a campfire, that way you know it has burned thoroughly.

Unless I'm mistaken, you can use green wood for this if you have the time and fuel to burn. You'll just lose a lot more mass and it'll take a lot longer and consume a lot more fuel to achieve the same results. It takes a long time for moisture to leave wood.

In short, no. The carbon in both charcoal and car exhaust was fixed by plants. To have your carbon from exhaust be made into charcoal, it would first have to go through photosynthesis by plants, fixed in the form of wood, then burned under limited oxygen to produce charcoal.

It can, though typically activated charcoal is used instead. The main difference between the two is that activated charcoal has a much higher porosity and therefore surface area. This means that it will absorb impurities significantly better than raw charcoal. If making an emergency water filter, raw charcoal will work just fine. For non-emergency commercial or consumer use, you want to use activated charcoal/carbon instead.

No. The type of charcoal you're looking for is activated, which is done by using calcium chloride to remove impurities from the charcoal, making it essentially pure carbon.

You will get about 1/4 as much charcoal by weight as wood that you put in. 100 pounds of wood will yield about 25 pounds of charcoal.

All varieties of eucalyptus ("gum trees") are dense hardwoods, especially suited for charcoal production. Red Gum, Ironbark and any species with "box" in the name are particularly good.

In the written description, it says cherry, oak or hickory is best.

Other hardwoods will produce better charcoal than bamboo, as they are denser and will last longer.

Different types of wood will burn differently, but generally, the more charcoal you want, the more fuel (in this case, wood) will be needed to create the charcoal. I would start with half as much wood underneath than whatever amount is being made into charcoal. From there, let the fuel burn away and then check for charcoal. Then, check to see how much charcoal was made and how much of the wood was not charred enough. This will give you an idea of what proportion you need between wood for charcoal and burning wood underneath. You can separate the charcoal from any wood that hasn't burned and use the remaining wood for making more charcoal.

Yes, in smaller scale and using the proper wood (hard branches of willow and hazel are the best).

Charcoal can be made from any thing containing carbon, so if it has carbon then you can use it.

If the charcoal is made from wood that contains no man-made chemicals, if the wood is well charred so that all the tars have been cooked out, and as long as the charcoal has been given a wash with potable water to remove the carbonates (ash), then there is no problem using your charcoal for purifying water. However, there must be a balance between charcoal size and retention time for all the water to interact to be purified.

It will. The goal is to "burn" the wood in the absence of oxygen, which is what the smaller barrel achieves no matter what's inside of it. The burn times may differ from what's listed here due to the increased surface area of the thinner wood, but the concept and the execution are the same.

Green coal is a reference to bituminous coal that has not been heated or "coked". Nothing to do with charcoal.

Square commercial charcoal in the form of briquettes if made by pulverizing charcoal and other fillers, which is made into a slurry, then formed and dried. To get similar chunks of charcoal that size, you will have to cut and split your wood to size and then make into charcoal. Much of it will split and break, so you'll end up with other pieces in addition to your desired chunks.