The Liebig condenser was invented by the German chemist Justus Baron von Liebig. It is a piece of laboratory equipment where a coiled glass pipe goes through a water jacket (a glass cylinder through which water constantly flows). It is used in distillation to condense vapors into liquid. The Liebig condenser is much more efficient than a simple retort due to its use of liquid cooling. Water can absorb much more heat than the same volume of air, and its constant circulation through the water jacket keeps the condenser's temperature constant. This makes Liebig condensers very useful for fractional distillation.