Pottery is the ceramic material which makes up pottery wares, of which major types include earthenware, stoneware and porcelain. The place where such wares are made by a potter is also called a pottery (plural “potteries”). The definition of pottery used by the American Society for Testing and Materials (ASTM) is “all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products.”
Pottery is made by forming a ceramic (often clay) body into objects of a required shape and heating them to high temperatures in a kiln which removes all the water from the clay, which induces reactions that lead to permanent changes including increasing their strength and hardening and setting their shape. A clay body can be decorated before or after firing; however, prior to some shaping processes, clay must be prepared. Kneading helps to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed. This is called de-airing and can be accomplished either by a machine called a vacuum pug or manually by wedging. Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it is shaped by a variety of techniques. After shaping, it is dried and then fired.