We investigated the relationship between the frothing and foam stability of beer and the surface properties of various kinds of drinking vessel (glass mugs and 6 kinds of ceramic mugs), whose size and shape were almost the same. Although the initial bubbles produced when pouring beer into a mug have been thought to depend on the gas created by the mechanical stirring and on the air adsorbed to the surface of the beer mug, we considered that the frothing and foam stability of beer in the mug might also be related to the shape and size of scratches and on the wettability of the surface of the beer mug. The mechanism for continuous bubbling was investigated by a theoretical equation which showed that the size of a bubble produced on the surface of the beer mug was significantly correlated with the wettability and shape of scratches on the surface, and that the place where a bubble was continuously produced was where air remained to form the nucleus of the next bubble after the previous bubble had been released.
