Stoneware pottery has been around in the South since the Southeastern US began to rise out of the huge forests of pine and red clay. Most of the early potter were English and German trained. Most were not overly fond of having to reinvent themselves in this land where none of the traditional materials they used in Europe had really been prospected for here in America. Most folks here were trying to stay warm and dry and keep from starving to death. Someone had to find, tested and validated these materials. We'd still be eating Cheerios out of cupped hands if someone hadn't done the work.
Stoneware is what the name indicates. Clay fired into rock. Stoneware will be here in some form when Gabriel blow he hawn. Red ware, the other pottery medium is softer and more or less usless for storage, but is used for table ware, churns and garden ware. Both Redware and Stoneware are made in the Southern States, but stoneware wins the prize for durability...storage vessels were vital in those days.
So, how did the process come to be a cottage industry in the South? Clay is as prevalent as rock. Erosion of ancient rocks and mountains left long trails of water that contain the fruits of the erosion process. These trails were creeks, streams and rivers. As they tumbled along they deposited mud, silt, and CLAY. Potters use various methods of finding it on creek banks and in swampy places and bottom lands.
Glazes were another problem. The glaze is what give a pot it's color, protects the surface from abuse, and keeps the contents from a certain amount of spoilage. Most of the glaze materials used in Europe weren't readily available, but were there for the digging...and dig they did.
The German and Moravian potter had brought a salt glaze tradition with them. Simply said, they start firing the pots in the kiln, and toward the upper end of the firing cycle, salt is introduced into the kiln chamber through port. NaCl sodium and chlorine...table salt. The chlorine goes up the chimney as a gas,(just don't take a deep breath) and the sodium adheres to the pot...a beautiful gray green surface. It isn't a very hard glaze, but it did the job. Now, folks in the South had more uses for salt than using it to glaze pots...curing meat, for one, not having the advantage of built in refrigeration like our northern neighbors, but we didn't have to shovel snow...
Providence provided...a Jesuit priest came into South Carolina, and announced he'd been to China and seen potters there use a glaze made from wood ashes mixed with water and "other ingredients" . Those are always a potters secret...sorta like magic potions. No Yankee ingenuity required; the Southern potters had an abundance of ashes, clay and "fines" or fine silica found in streams and ditches to stir up together and dip the pot in. A hard, simple to make, beautiful glaze was the result.
The glaze makers rule of thumb the FAG code. F for Feldspar, found as one of the three ingredients of granite, pretty common in the US. A for alumina, found in clay, and G, for a glass maker, something like silica from a road ditch, or ground up glass. Add a little water, cook it to about 2000 degrees. 2000 degrees! How do you get that kind of heat?