"The making of charcoal, literally the distillation of wood to its carbon content, was an important process during the first half of the nineteenth century. Because it burned hotter and cleaner, charcoal was considered superior to wood. It provided fuel for both the furnaces which produced the iron and the forges of the blacksmiths who shaped it.
The first person to discover the seemingly magical properties of charcoal has long since been lost to human memory. What is known is that it may have been used in Europe as early as 5,500 years ago and was the "smelting fuel of the bronze and iron ages." Across many centuries charcoal was used in the smelting and shaping of metals, the production of glass, as a purifier of food and water, and in gunpowder; its by-products included a liquid used in the Egyptian embalming process.
The first method for producing charcoal probably involved the pit kiln process in which wood was slowly burned in a shallow pit covered with soil.
However, in many areas this eventually gave way to the more efficient and more manageable above ground forest kiln method. The charcoal maker, or collier, became an important figure. The demand for charcoal was such that in areas like Great Britain the woodlands were all but stripped and alternative fuel sources such as coke had to be sought. This was not initially the case in the heavily wooded United States."