Cratering phenomena are defects that appear as a microscopic crater on the surface of the ceramic body, typically during the drying phase of a freshly applied aqueous suspension. It is an application-related issue that results in the unevenness of the suspension layer due to one or more localized depressions.

This defect, which can be detected as early as the glazing line and not only after firing, may arise from various causes. Some are linked to impurities present in the ceramic raw materials, while others—for instance—may result from the improper use of defoamers.

This episode aims to outline the main causes behind this issue, highlighting the underlying mechanisms and providing practical suggestions and/or precautions to help prevent or eliminate its occurrence.