Bisque firing is an initial firing that takes the pots through a chemical change, transforming the raw clay into a ceramic material.
Bisque firing is another product of the Industrial Revolution. For thousands of years, pots were baked using a process called single firing. After the pots were made and raw glazed, they were fired very slowly over a couple of days in a wood kiln. Because this process requires much skill and care, single firing, though ideal for the village potter, does not lend itself well to producing large quantities of identical pots. So bisque firing was developed to allow mass production of pottery in factories. Bisque firing is an initial firing that takes the pots through a chemical change, transforming the raw clay into a ceramic material. Fired to about one-third of their maturing point, the pots are still very porous, and will readily absorb the glaze that is applied to them. After bisque firing, the pots are glazed and then fired a second time, which melts the glaze and sets the clay. Bisque firing enables pottery to be produced more uniformly than single firing. It also allows the process of making of clay vessels to be broken down into separate steps, performed by different people, each with limited knowledge of the process as a whole. For example, one person might specialize in making pots, another in firing, yet another in applying glazes, enabling an assembly-line approach to making clay pots on a large scale. Though originally developed to support mass production, bisque firing has become the firing method most commonly used by artisan potters. Yet a number of potters, ourselves included, are taking steps to return to single firing. We know that single firing is advantageous because it requires less energy than bisque firing and saves a considerable amount of the potter’s labor. But we also believe that there may be other benefits to single firing that we won’t see until we have more experience with it.