Download 14 January 2004 Issue

In the early days of distilling essential oils for medicine and fra grances, the simple pot-still was the only tool available to the chemist. By slowly heating a liquid sample and collecting the vapor, the compound was separated into its various components according to their relative boiling points. To refine the separation and concentration process, the time-consuming distillation process was performed two or three times.

In the beverage alcohol industry, it’s the distiller’s job to separate the ethyl alcohol that we drink from the light alcohols, esters, aldehydes and fusel oils produced during the fermentation process.

As the fermented wash is heated, the lightest alcohols and esters, known as the heads, are the first elements to be condensed from a still. Once the heads have been set apart, the heart of the spirit is collected. Lastly, the tails, which contain heavier oils and congeners harmful to the caliber of the spirit are boiled from the wash. Inasmuch as the heads, heart and tails are essentially colorless when they are condensed, the distiller must be skilled in judging the cut among them. In addition to monitoring the alcohol content of the condensate, subtle deviations in viscosity suggest the presence of the heads, heart or tails, but ultimately it is the distiller’s senses of smell, taste and experience that determine which part of the distillate will be used and which portion will be discarded.

Over the centuries, the basic pot-still, which resembled a copper teapot with a long spout, was modified to include retorts, or additional distilling pots. These improvements to the basic still essentially allowed double distillation to be accomplished during the time it previously took to distill a single batch of product. In the continuouscolumn still, fermented wash is introduced to the top of the column to cascade down through a series of baffles while steam, piped to the bottom of the tower, heats the wash. With the invention of the column still in the 19th century, the science of distillation advanced with two advantages over the simple pot-still.

First, through a series of tubes attached to the vertical still, several product streams could be condensed that reflected the temperature profile of the still and the composition of the mixture being distilled.

Second, by taking the distillation process from a batch to a continuous process, production was greatly improved. Most continuous-column stills are configured with two or three columns in series in order to refine the distillation process, but the single-column still most accurately reflects the distillation properties of the pot still while maintaining the advantage of greater production.

Among connoisseurs of fine spirits, it is generally agreed that the best spirits are made in pot stills, which contribute to a broader flavor profile than is generally associated with spirits produced in multiple-column stills. However, in the hands of a skilled operator, column stills are quite capable of producing comparably excellent spirits while providing the advantages of a continuous process.

Notwithstanding the fact that pot stills are simpler and cost less than column stills, the pot still also has the advantage of enabling small quantities of wash to be distilled with a high degree of control at a cost that is in line with the production capability, and market, of the small distillery. In the final analysis, regardless of whether the spirit is a product of a complex column or the simplest still, ultimately, it’s the practiced art of the distiller that determines the quality of the drink in your glass.