You really can make your own charcoal at home – even if you live in the suburbs! If you use the indirect method, which burns the gasses, and use a clean burning fuel (such as natural or LP gas) the emissions are mostly water vapor with very little smoke. It is not difficult to do and, even when burning waste wood to provide the carbonizing heat, the process requires less time and attention than barbecuing a rack of ribs in a wood burning smoker.
Why would anyone want to make their own charcoal? For one thing, good hardwood lump burns hotter and cleaner (but faster) than briquettes and is much easier to light. You also know where it came from, what it contains and what was done to it en route. There are endeavors other than barbecue which require high quality natural charcoal: It is still the preferred fuel for forges and blacksmithing. Folks who make their own fireworks and black powder need specialty charcoals with specific burning properties such as that made from willow or grapevine.When grilling or even barbecuing in most pits with charcoal and wood, the quality of the charcoal is really not that critical.
There is enough airflow to dilute impurities. Now that I have a Weber Smoky Mountain, (WSM) though, charcoal quality, impurities and additives become very important. It is a great little cooker and will do everything folks say it will, BUT there is precious little airflow and the meat is bathed in smoke for hours. What you burn, you eat! I have read how briquettes are made by the major manufacturers. That leaves me either burning to coals, which is impractical for the small amount of coals needed by the WSM, or making my own lump, which is just a way to burn to coals and store them for use as needed. Being somewhat of a skinflint, I would rather utilize the resources at hand and make my own lump as opposed to buying it. My objective in this endeavor was to use existing technology to design a simple, cheap, reliable and efficient method for the small scale production of charcoal for home use utilizing readily available materials and minimizing the release of pollutants.
How to make Charcoal:
Timing is important. Plan to start your burn on the hottest, muggiest day of the year with a comfort index of at least 105 and air quality just above the minimum to sustain life. These conditions won’t affect the charcoal process at all but will ensure that the experience is memorable. There are two basic methods of making charcoal: direct and indirect:
- The direct method uses heat from the incomplete combustion of the organic matter which is to become charcoal. The rate of combustion is controlled by regulating the amount of oxygen allowed into the burn and is stopped by excluding oxygen before the charcoal itself begins to burn. This is the ages old method used by colliers to make charcoal in a pit, pile (clamp) or, more recently, in metal or masonry chambers (kilns). See the links below for more information.
- The indirect method uses an external heat source to “cook” organic matter contained in a closed but vented airless chamber (retort). This is usually carried out in a metal or masonry chamber (furnace). The indirect method results in a higher yield of high quality charcoal with less smoke and pollutants and requires less skill and attention than the direct method.