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 ...
as
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 (he ...
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 amoun ...
.
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
centner
The quintal or centner is a historical unit of mass in many countries which is usually defined as 100 base units, such as pounds or kilograms. It is a traditional unit of weight in France, Portugal, and Spain and their former colonies. It is com ...
s. 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