A temper is a non-plastic material added to clay to prevent shrinkage and cracking during drying and firing of vessels made from the clay.[1] Tempers may include:
Some clays used to make pottery do not require the addition of tempers. Pure kaolin clay does not require tempering.[6] Some clays are self-tempered, that is, naturally contain enough mica, sand, or sponge spicules that they do not require additional tempering.[14][13]