Charcoal is an important natural resource which has been used throughout history for many purposes, including art, medicine, and chemistry. However, its primary use has been as a source of fuel. Although charcoal can be made from a variety of animal and vegetable products, the most common commercially available charcoal is made from wood.
Wood charcoal is primarily made up of carbon, called char, with some ash residue from the original wood remaining. Wood charcoal is made by heating wood in a low-oxygen environment, over the course of several days. This process dehydrates the wood and burns off roughly 75% of the original wood volume, mostly volatile compounds such as water, methane, hydrogen, and tar.