Column still
From Free net encyclopedia
A column still also called a continuous still, patent still, or coffey still is a variety of still that consists of two columns. The first, called the rectifier, has steam rising and wash descending through several levels. The second column called the analyzer carries the alcohol from the wash where it circulates until it can condense at the required strength. Column stills behave like a series of single pot stills, except in a long vertical tube. The tube is filled with either porous packing, or bubble plates. The rising vapor, which is low in alcohol, starts to condense in the cooler, higher level of the column. The temperature of each successively higher stage is slightly lower than the previous stage, and so the vapor in equilibrium with the liquid at each stage is progressively more enriched in alcohol. Whereas a single pot still charged with wine might yield a vapor enriched to 40-50% alcohol, a column still can achieve a vapor alcohol content of 96%.