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%. The term still is a contraction of the verb to distill. A still is an apparatus used to distill miscible or immiscible (eg. ... Deconstructing a Roman pillar. ... AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ... In physical chemistry, and in engineering, steam refers to vaporized water. ... The term wash can mean several things: Cleaning A wash is the act of cleaning. ... Wikipedia does not yet have an article with this exact name. ... In chemistry, an alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom, which in turn is bound to other hydrogen and/or carbon atoms. ...