Among the several issues that may arise along the glazing line, the excessive foaming within glaze suspensions is one of the most frequent and problematic. The phenomenon is already visible on the surface of the glaze inside the stirring systems but consequences can persist even after the end of the production, that is after the firing cycle. Chemistry speaking, what is foam? What are the causes of its presence and what do we need to know to prevent its formation or to remove it in case of unexpected phenomena?