Abstract: An apparatus for automatically dispensing containers of a prepared liquid composition in which a plurality of containers each holding the ingredients for a particular liquid composition are stored in a storate device and are delivered one at a time to a mixing station for addition of a measured amount of water. A rod-like electrode, e.g. sonotrode, vibrated within the sonic and ultrasonic frequency range is introduced through the open end of the container for effecting mixing of the added water and ingredients by immersion therein, and a portion of the added water is used to flush the electrode surface free of residual material while the container and electrode are being moved relatively apart to withdraw the electrode therefrom.