A mixing machine 1 comprising a mixing head 3 having element(s) for connecting to a receptacle to form a mixing container. The mixing head 3 is pivotably supported in a frame 2 such that the mixing container can pivot for the mixing process. The mixing head 3 has at least one rotationally driven mixing tool whose drive shaft 23 extends through the wall of the mixing head 3. The mixing head 3 has a double wall with a perforated inner wall 8. The perforations form a fluid path from the chamber surrounded by the inner wall 8 to the intermediate wall chamber 10. The intermediate wall chamber 10 is connected to a pressure adjustment device for adjusting the pressure. A flexible liner 15 is arranged in the mixing head 3 on its inner surface, which liner 15 can be fixed to the inner wall 8 of the mixing head by applying a vacuum.