Abstract: During the application of a coating material to paper or to cardboard, air inclusions in the coating material can interfere with production in various ways. It is proposed to measure the air inclusion content in a coating material by taking samples of the material. Each sample is introduced at a predetermined first pressure into a measurement cell which has a closed first volume. This closed first volume in then reduced to a closed second volume at which a predetermined second pressure that is greater than the first pressure prevails in the measurement cell. The air inclusion content of the coating material can then be derived from the change in volume required to produce the predetermined pressure change. On the basis of the measured values, degassing equipment can be optimally adjusted.