The unit consists of a spherical metal chamber filled with dry ice, a twisted stabilizer fin, and 2 propelling nozzles. As the dry ice cools the beer, it sublimates and the gas is channeled through the propelling nozzles causing the whole unit to spin. The fin plays the double role of stabilisation and encouraging convection in the beer glass. Neither the dry ice nor its gas comes in contact with the beer leaving the taste authentic. It looks like a designer alien spaceship is slowly spinning in the frothy beer, releasing a helix of white mist.
It makes for quite a show adding a theatrical element to a simple process.