Abstract: A vacuum processing apparatus having a chamber, defining an open bottom, and having a closed top, the size of such chamber being sufficient to receive a processing container, and the height of such chamber being sufficient to fit completely over such container, and stirring means extending downwardly within the chamber to extend into the container, when enclosed within said chamber, and having power operated rotating means and sealing means around the open bottom of the chamber, for forming a good air-tight seal, means for raising and lowering the chamber and means for evacuating air from said chamber.Also disclosed is a method of processing the contents of a container, in which the contents are first stirred in a container by a stirrer at atmospheric pressure and are then further stirred, in the same container under vacuum, by means of a stirrer located in a vacuum chamber.