Tar Kiln from Eschbach

Replica

The tar kiln built from field stones is a reconstruction. Its base was built following the measurements of an archaeological find in the forest of Eschbach, and its top is fashioned after the last surviving overground kiln in Hesse at Kirtorf in the Vogelsberg district. As late as between 1850 and 1900, tar kilns were used in the forest areas of Hesse to produce tar from pine wood through a process of distilling sap by corroding wood fibre at high temperatures. The controlled burning process yielded pine tar, tarry cart grease, pitch and the valuable by-products charcoal and wood ash (potash). The actual burning and distillation process extended over a full week, during which the kiln had to be kept at a consistent heat. This required a stoker to be at hand around the clock – the so-called Schmerschorsch.

The innermost core of the double-lined kiln, a cauldron-like chamber made of halved bricks, has a diameter of circa two metres and a height of circa 2.50 metres. Its base is dug out towards the centre. A drain pipe, fashioned from an oak trunk, channels the fluid products outside the kiln. At earth level, opposite the stokehole, the kiln has an opening for cleaning and feeding fuel that is sealed during the burning process. The second opening on top of the kiln can be closed with a heavy iron lid. The inner chamber is surrounded by a second lining of fieldstone, measuring a diameter of about four metres. The hot combustion gasses emitting from the firing into the cavity between the core and the lining help heat up the kiln uniformly. Vent holes at the top of the kiln allow for regulating the distribution of heat, depending on the direction of the wind.