Potters use natural processes analagous to those occuring in soils in order to manipulate and control the properties of their clay bodies. One of the major differences, however, is the element of time. Aging is a standard technique for increasing the plasticity of a clay body, and can produce some desired effects within a matter of weeks. Some Japanese potters traditionally use clays which were collected and prepared by their grandparents. These bacteria can be added from an older batch of clay, from a package of yeast, or they can simply be encouraged to colonize the wet clay with the addition of starches to the clay body.
Some potters add acid directly to an aging clay in the form of vinegar or citric acid.
The pH conditions of a soil critically affect the charges along the edge sites of its constituent clay minerals and thus pH conditions often control whether a clay is flocculated or dispersed. The addition, by some potters, of soap to an aging clay further confuses the issue, bringing OH- onto the scene. Thus suggesting that a dispersed clay would be more plastic. Probably different potters manipulate the aging process towards flocculation or dispersion, based on their particular demands. In sum, the aging process affects plasticity from a variety of angles.