Fire clay and 3% fine mullite make it great for both hand and wheel work.  Cone 6 Shrinkage 11% Absorption 1% We recommend 553 for most
beginning pottery students. 

Grog is pre-fired crushed clay. It is about the size and consistency of sand. Grog is added to
clay bodies to reduce shrinkage and increase the strength of the clay during drying. Since
grogged clay bodies dry more slowly, they are less likely to crack during drying. Grogged clay
bodies are suggested for sculptures and projects which vary in thickness. We highly
recommend that beginners start with a grogged clay body.

Ungrogged clay bodies are smoother, and generally less abrasive on potters’ hands and
fingernails. Clay bodies without grog are more difficult to use but provide smoother finished

Shrinkage: All clay shrinks as it dries, then shrinks again during firing. Clay shrinkage is
published by clay manufacturers as a percentage, which includes both drying shrinkage, and
firing shrinkage. Clay that shrinks more quickly or has a higher percentage of shrinkage is more
likely to crack during drying and firing.