==Origins==
Though the exact moment in history of when lambic producers adopted this style of stoneware is unknown, the style of pottery dates back to at least the early 1900's. The proper name for this stile style of pottery is ''Keulse pot'' or 'Cologne pot'. As the name suggests, this style of pottery originated in the Cologne area of Germany. The Keulse pot style carries on a tradition that dates back to the late-13th and 14th centuries in the Rhine River watershed. The town of Sieburg, Germany (30km from Cologne) is the first recognized center of this style of pottery. The pottery is characterized by its use of salt glazing to achieve both its glossy look and its waterproof finish and its strong cobalt blue finish which originated in Poland. <ref name=Keulsepot> History, Keulse Potten - http://www.historieroermond.nl/keulseaardewerk/keulseaardewerk.htm (Dutch) </ref> It is unclear when lambic producers specifically adopted and began to brand this stoneware with their own names, though examples from the early 20th century do exist.
The pottery ranges from pitchers, to jugs, to large pots of 20 to 30 liters. The larger pots were used primarily for storing vegetable and meat preserves after harvest. In Germany, Holland, and Belgium the pottery is commonplace and still produced today, though not generally used for the traditional preservation process.