Abstract: An apparatus for batch distilling a liquid at sub-atmospheric pressure, without the aid of a vacuum pump. The apparatus includes an evaporator section having a valved entry port through which a batch of liquid in a first atmospheric condition is added to the evaporator section. A condenser section receives distillate and is in communication with the evaporator section. A valved vent is provided for sealing said apparatus from the outside atmosphere to form a second atmospheric condition which is sealed from the atmosphere after a heating element vaporizes said liquid into an initial sufficient amount of a first vapor to purge the first atmospheric condition from the apparatus through the valved vent. A condenser is disposed for condensing a sufficient amount of the first vapor to form a third atmospheric condition at a pressure below the first atmospheric condition, and for condensing a second vapor to produce distillate.