By Erica D’Elia – Assistant Lab Director
One of my favorite types of ceramics is the white salt-glazed stoneware which we have been finding Site 44FX0704 at Colchester. It’s beautiful. (Full disclosure: I wanted this stuff for my table at home; it turns out reproductions are pretty expensive. But. So. Many. Beautiful. Pieces. Not on this archaeologist’s salary. Maybe someday).
As the name suggests white salt-glazed stoneware is a white-bodied, non-porous stoneware, which was fired at a relatively high temperature (higher than earthenwares, but lower than porcelain). These pieces were wheel-thrown, or beginning around 1740, press molded. They are found in a variety of vessel types and are often tea- and tablewares such as mugs or plates. The very fragmentary nature of the pieces we find can sometimes make identifying a specific vessel type difficult.
The vessels were formed, sometimes decorated, and then they were placed into the kiln. The shiny exterior glazed surface was achieved by adding salt to the kiln during the firing process. At peak temperature salt is thrown into the kiln where it vaporizes and the sodium ions are released. They bond to any exposed surfaces they can find: the kiln furniture and the surface of the vessels. Salt then combines with, or melts, the surface of the pots which creates the layer of glaze and leaves the characteristic orange-peel effect on the surface. Here’s a video of potters demonstrating the process: https://www.youtube.com/watch?v=UbCce1kPU90.
White salt-glazed stoneware is what we call a diagnostic artifact. We are able to use it to date our deposits because we know when it was manufactured. Additionally, some of the decorative styles and motifs can be dated as well, allowing us to further refine the date range for our assemblage. Manufacturing dates for white salt-glazed stoneware are from approximately 1685-1785, though it peaked in popularity between 1720-1770. This ware was more durable than the tin-glazed earthenwares commonly used in the second quarter of the 18th century and it was gradually replaced by white refined earthenwares by the end of the century.
There are several decorative styles that we see on white salt-glazed stoneware. Two in particular that we have found are molded designs and incised and painted “scratch blue.” Beginning around 1740 plates often had press molded designs around the marley (flat border) of the vessel. These designs tend to be standardized such as the “dot, diaper, and basket” and “barley” motifs. Scratch blue vessels had fine lines or designs cut into the surface, which were then neatly filled with blue paint (cobalt oxide). Beginning around 1760 debased scratch blue designs were produced where excess cobalt oxide was allowed to seep out onto the surface surrounding the incised decoration.
The presence of this ware, coupled with tin-glazed earthenwares and creamware helps to establish a date range of use for Site 44FX0704 to the mid to late 18th century.