How charcoal is made
Charcoal burners bury a smoldering pile of logs on purpose, starving it of air so the wood cooks without burning.
- stations
- 5
- things upstream
- 1
- raw source
- 1
- step from the ground
- 1
The short version
Charcoal is wood heated strongly in minimal oxygen until water and volatile compounds are driven off, leaving mostly carbon. Traditional burners stacked billets in a covered pile, while modern plants use retorts that burn the released gas for heat. Wood yields about a quarter of its weight as charcoal.
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Stack the billets
Wood billets are piled on end in a cone around a central flue, with air holes at the bottom. The whole pile is covered with turf or moistened earth.
Goes in -
Light it and smother it
The pile is lit gradually and kept starved of air. Only part of the wood burns, and its heat carbonizes the rest.
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Tend the slow burn
A collier, as charcoal burners are called, watches the smoke and adjusts the air. The skill is managing the heat so the wood chars without turning to ash.
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Cool and rake out
Once the sealed pile cools, the black lumps are raked out.
about 25% by weight
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Or carbonize in a retort
Modern plants cook wood in closed retorts, and burn the gas it releases to supply the process heat. Yields can reach 35 to 40 percent.
Worth repeating
- At its peak, charcoal burning employed hundreds of thousands of people and was a major cause of deforestation in Central Europe.
- Retorting also recovers by-products such as wood spirit, pyroligneous acid and wood tar.
- Activated charcoal is heated to about 900 °C in an inert gas to create tiny pores.
Back to the ground
Follow every input upstream and charcoal starts as these 1 raw source.
Open the whole family tree
Where it goes next
Charcoal feeds 4 lines directly and reaches 195 things in total.
Further down the line
Keep walking
Sources
Cite this page: "How charcoal is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/charcoal