Karlsbad-style coffee maker

[15][16][17][13][18][nb 3] In contrast to French drip coffee pots, they all use a special double-layered conically cross-slitted strainer made from through-glazed porcelain[1][19][20][11] as well as a water spreader with six (or, in the larger models, more) large round holes[nb 4] to ensure an even water distribution and reduce the agitation of the coffee bed, a method sometimes also called cake filtration.

[31][29][11][30] As a product of the fin de siècle[9] the original so-called Karlsbader Kaffeemaschine ('Karlsbad coffee maker') was invented by Oswald von Thun und Hohenstein's [de] factory Thun'sche Porzellanfabrik of Klösterle an der Eger (now Klášterec nad Ohří) near Karlsbad (now Karlovy Vary),[32][33][34][35][36][37][38] which patented a special cross-slitted filter sieve in 1878.

[3][4][5][6][7][8][10][nb 1] Producing lithophanes, the company, which was founded in 1793/1794, already had experience manufacturing very thin and fragile porcelain for decades.

[12]: 133 [13]: 125 Porzellanfabrik Siegmund Paul Meyer (1899–1920) (SPM) / Erste Bayreuther Porzellanfabrik Walküre Siegmund Paul Meyer GmbH (1920–2016) / Porzellanfabrik Walküre GmbH & Co. KG (2016–2019): Friesland Porzellan (FPM): Rosenthal (similar to SPM/Walküre form "599" without rills): Bauscher Weiden (similar to SPM/Walküre): Hutschenreuther (similar to SPM/Walküre form "599" without rills): Haas [de] & Czjzek [de] (H. & C.), Schlaggenwald: TK Thun (Thun Karlovarsky): Unidentified: In the 1880s,[62] Max Thürmer, a coffee roaster of Dresden, Germany, founded in 1879, advertised Karlsbad coffee and somewhat later also coffee makers (of unknown type) in various newspapers.

[66] While the permanent filter in early of his devices still featured round drilled holes like in French drip coffee makers, later units used a double-layered cross-slitted filter construction similar to that found in Karlsbad coffee makers, but deliberately with a much coarser grid, with a large air gap between the layers, and using ceramics instead of porcelain.

[68] While his construction was considerably different, it also featured a valving mechanism (through a rotatable saucer), a through-glazed porcelain filter with triangularly-arranged slits and with an air space below.

Since c. 1952 (and up into the 1970s) the Neuerer Porzellanfabrik in Oberkotzau, Germany, the successor of Porzellanfabrik Greiner & Herda, manufactured coffee percolators named Aromator, which featured double-layered cross-slitted porcelain filters similar to those used in Karlsbad coffee makers,[74][75] and thus not requiring any paper filter rings.