Differences between the three major types of Corinthian amphoras produced between the seventh and second centuries B.C. provided the basis for an investigation of how physical properties and processing history of these amphoras are related to technological and visual style. The earliest amphoras, type A, had to be hand built to permit addition of potash flux and coarse temper, and were initially fired rapidly in reduction at low temperature, then oxidizing at high temperature to promote glass formation and impermeability to liquids. Type A.0 and type B are permeable, A.0 being made from various clay body compositions, and B from calcareous clay without potash. Both were fired at lower temperatures than type A. Possible reasons for changes in technology are discussed.