Column still

This technique is frequently employed in chemical synthesis; in this case, the component of the still responsible for the separation is a fractionating column.

This, along with the ability to produce a higher concentration of alcohol in the final distillate, is its main advantage over a pot still, which can only work in batches.

Stripped (approximately alcohol-free) liquid is drawn off at the base, while alcoholic spirits are condensed after migrating to the top of the column.

Further enrichment is only possible by absorbing the remaining water using other means, such as hydrophilic chemicals or azeotropic distillation, or a column of 3A molecular sieves, like 3A zeolite.

[5] These early French stills were suited to the production of wine, but deficient in the processing of the residual solids found in whiskey mashes.

[6] These French designs were further developed and improved upon by a number of Irish, British, and German contributors, to allow for use in the distillation of whiskey and other liquids.

The still included a labyrinth of partitions, which allowed the wash to flow gradually and continuously over the heat, with increased contact between the vapour and liquid phases of the distillate.

[8] In 1823, Jean-Jacques St. Marc, a French veterinary surgeon attached to Napoleon's personal staff, moved to England where he sought investors in his "Patent Distillery Company", which was to distill potato brandy.

Piston strokes were used to vapourise the wash and feed it into a horizontal cylinder which was divided into a series of compartments using cloth.

[7] Educated at Dublin's Trinity College, Coffey had ample opportunities to observe all manner of still designs having worked as a distillery excise tax collector for a quarter of a century.

[5] This new continuous distillation method produced whisky much more efficiently than the traditional pot stills,[14] without the need for cleaning after each batch was made.

[6] However, with technological improvements, most notably the introduction of steam regulators in 1852, the Coffey still found widespread use in alcohol production across Europe and the Americas.