I tested a charcoal retort based on the Hookway retort method using only primitive materials. A normal retort is one in which the sealed chamber of wood is inside a furnace and the heat drives off the volatiles converting it to charcoal. The Hookway retort, invented by James Hookway (see original video: • The best charcoal retort kiln in the ... ) has furnace, a metal pipe, inside the sealed chamber of wood, so the heat conducts out into the wood converting it to charcoal. In addition to this, escaping volatiles from the wood enter the pipe where they are burnt, adding further heat. After a while, no more wood is added to the furnace as it runs entirely of wood gas. In my version I made a clay pipe and tested it. It did produce some charcoal but most of the wood remained unburnt. This was due to the poor heat conductivity of the clay pipe relative to the metal pipe of the original. The charcoal it did produce from wood touching the clay pipe directly, was of excellent quality. An