A potash works (german: Aschenhaus, ''Aschenhütte'' or ''Potaschhütte'') was a subsidiary operation of a

glassworks Glass production involves two main methods – the float glass process that produces sheet glass, and glassblowing that produces bottles and other containers. It has been done in a variety of ways during the history of glass. Glass container ...

in the Early Modern Period. The latter needed

potash Potash () includes various mined and manufactured salts that contain potassium in water-soluble form.

, as well as

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

and

lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...

raw material A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...

s for the manufacture of

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

. Potash acted as a

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ph ...

in the production process, that is by mixing it with

quartz sand Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

it significantly reduced the

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

of the latter. To make potash the glassworks built potash huts or works in the vicinity, in which

wood ash Wood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds along with other non-combustible trace elements presen ...

and vegetable ash was gathered by

ash burner The job of an ash burner (german: Aschenbrenner) or potash burner (''Pottaschbrenner'') was to burn wood for industrial purposes. From the ashes, the potash needed in dyeing, in soapmaking and in glassmaking could be made by leaching and boiling ( ...

s and initially washed in water and then vaporized; the whole process being known as

leaching Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to: * Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amou ...

. Contemporary witness, teacher and local historian, Lukas Grünenwald, recorded the recollections from his youth in Dernbach in the

Palatinate region The Palatinate (german: Pfalz; Palatine German: ''Palz'') is a region of Germany. In the Middle Ages it was known as the Rhenish Palatinate (''Rheinpfalz'') and Lower Palatinate (''Unterpfalz''), which strictly speaking designated only the wes ...

:Helmut Seebach: ''Altes Handwerk und Gewerbe in der Pfalz.'' Vol. 3: ''Pfälzerwald. Waldbauern, Waldarbeiter, Waldprodukte- und Holzwarenhandel, Waldindustrie und Holztransport.'' Bachstelz-Verlag, Annweiler-Queichhambach et al., 1994, , p. 116. The consumption of wood in the process of making potash was extremely high, which is why the glassworks were frequently established in areas of extensive forest (hence the term

forest glass Forest glass (''Waldglas'' in German) is late medieval glass produced in northwestern and central Europe from approximately 1000–1700 AD using wood ash and sand as the main raw materials and made in factories known as glasshouses in forest a ...

). For example, the documents of the forest glassworks of

Spiegelberg Spiegelberg is a municipality in the Rems-Murr district of Baden-Württemberg, Germany. History Spiegelberg's name comes from a glassworking manufactory built in the town in 1699 that produced mirrors from 1705 to 1794. Geography The municipal ...

in the

Swabian-Franconian Forest The Swabian-Franconian Forest (german: Schwäbisch-Fränkischen Waldberge, also ''Schwäbisch-Fränkischer Wald'') is a mainly forested, deeply incised upland region, 1,187 km² in area and up to , in the northeast of Baden-Württemberg. It fo ...

, which was in operation from 1705 to 1822, had an annual demand for potash of approximately 800 centners. Because one

cubic metre The cubic metre (in Commonwealth English and international spelling as used by the International Bureau of Weights and Measures) or cubic meter (in American English) is the unit of volume in the International System of Units (SI). Its symbol is m ...

of wood (750 kg) only produced 1 kg of potash, this glassworks thus needed around 40,000 cubic metres of wood per year. Even today the names of some settlements still recall the former potash works. For example, two hamlets in the municipality of

Mainhardt Mainhardt is a municipality in the district of Schwäbisch Hall in Baden-Württemberg in Germany. See also * Mainhardt Forest The Mainhardt Forest is a hill range up to {{GeoQuelle, DE, BFN-Karten in the counties of Schwäbisch Hall and Heil ...

, Germany, are called ''Aschenhütte''.

References

Literature

* Marianne Hasenmayer: ''Die Glashütten im Mainhardter Wald und in den Löwensteiner Bergen.'' In: Paul Strähle (ed.): ''Naturpark Schwäbisch-Fränkischer Wald.'' 4th revised and expanded edition. Theiss, Stuttgart, 2006, {{ISBN, 3-8062-2033-6, pp. 108–128 (''Natur – Heimat – Wandern''). Glass production History of glass Forest history Potash