stoneware

Stoneware is a compound of 'stone' and 'ware' (goods, merchandise). The word appeared in English in the 1680s to describe ceramics fired at high temperatures — between 1,200 and 1,400 degrees Celsius — where the clay vitrifies (becomes glass-like) and produces a hard, dense, non-porous body. The name was descriptive: stoneware felt and sounded like stone when tapped. It was not stone. But it was closer to stone than earthenware, which remained soft and porous.

Chinese potters mastered stoneware production during the Shang dynasty, around 1400 BCE — more than three thousand years before the English word existed. The technology required kilns capable of reaching temperatures that European potters did not achieve until the medieval period. German potters in the Rhineland were among the first in Europe to produce true stoneware, beginning around the 1200s. Cologne, Siegburg, and Westerwald became centers of stoneware production, exporting salt-glazed jugs and tankards across northern Europe.

Salt glazing — throwing common salt into a kiln at peak temperature to create a glassy surface — was a German innovation of the 1400s. The sodium reacts with the silica in the clay to form a thin, orange-peel-textured glass coating. No other technique produces this surface. German salt-glazed stoneware tankards became so associated with beer drinking that the form — a cylindrical grey-and-blue jug — is still the default mental image of a beer stein.

Modern stoneware dominates the dinnerware market. Most restaurant plates, coffee mugs, and mixing bowls are stoneware — more durable than earthenware, less expensive than porcelain. The word has become so common that most people do not think about what it means. It is not stone. It is clay pretending to be stone, and doing so convincingly enough that the pretense became the name.