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Distillation

Types of Stills

  • Pot stills were the first type of still invented and are less technical than the more modern continuous still, producing a much more artisanal spirit.


    A pot still uses a kettle to purify an alcoholic liquid. Based on the principle that ethanol vaporizes at 173.1˚F and water vaporizes at 212˚F, a wash containing a small quantity of ethanol can be purified, by evaporating and condensing the ethanol and leaving the water behind. This process removes any impurities, or heads and tails, that are naturally present.

    As the wash is heated the first substances to volatize and then condense are the heads, which are collected and removed. The next substances that come from the still will comprise the heart of the run, composing the spirit that will be kept. The master distiller determines the length of the heart based on the purity he/she is seeking in the outcome. The heart is followed by the tails, which are also removed. Often, the heads and tails are returned to the next batch to be distilled and run through the still again.

    Pot distilled spirits are usually passed twice through the still in order to improve the purity of the distillate. Occasionally, they are even distilled three times. This method of distilling is not the most efficient; it is time consuming, labor intensive, has low throughput. The distillate from pot stills lack purity, but these impurities called congeners are thought to add character to the distillate.

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  • The advent of the continuous or column still greatly changed the world of distilling, as it produces a much purer spirit than pot stills.

    The inventor of the patented still is disputed, with some citing Jean-Baptiste Cellier Blumenthal of France or Robert Stein of England as the creator, but history attributes it to Aeneas Coffey, an Irishman, who was issued the patent and used it to produce whiskey. This technology was advanced by the work of Jean-Edouard Adam, who invented a method for isolating the ethanol in wine.


    The continuous still heats cold wash by pumping it through a steam filled column called the rectifier into the analyzer, a column heated by steam. The wash is vaporized and rises through pipes into the rectifier where it travels through a series of perforated plates, cooling down gradually as it rises and condensing on each of the plates. The distillate is removed at the desired point, the plate. The steam escapes through the top, and the heavier liquids fall to the bottom of the rectifier and are eventually re-distilled.


    This method produces a much purer product that is also more neutral and has a higher percentage of alcohol, than distillate produced in a pot still, but also one with less defined character.


    After distillation, the distillate is reduced usually with water to between 40–60% ABV. In some cases, this is done prior to maturation though some spirits are not matured, while in other cases, there are long maturation regimes observed prior to the final blending.

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