blistering (ceramics) definition

Blistering is a glaze defect that involves bubbles on fired glaze surface that frequently burst and create hard craters.  The best way to avoid bubbles during high-firing is to use a short oxidation soak at the finish of the firing process in order to permit the surface defects to right themselves.  One can also use low-firing by elongating the firing process or through soaking the kiln when the time comes for maturation.