Credited to Ireland. Continuous stills were patented earlier, by Anthony Perrier of Cork and by the Scottish distiller Robert Stein in 1827 and 1828, and by Cellier-Blumenthal in France. Coffey's 1830 design is credited as the refinement that made continuous distillation reliable and commercially standard, and it was developed and tested at his Dock distillery in Dublin.
How it began
Aeneas Coffey was born in Dublin in 1780 and made his career in the excise service, where he inspected stills of every kind. After he retired he turned to continuous distillation, studying the continuous stills already patented by Anthony Perrier of Cork and by Robert Stein in Scotland. In 1830, when he was proprietor of the Dock distillery in Dublin, he applied for a patent on his own design. Patent 5974 was granted on February 5, 1831.
Before it existed
Distillers used the pot still, a large copper vessel in which one batch of fermented liquid was heated and the alcohol vapor collected and condensed. The still then had to be stopped, emptied and refilled for the next batch. Working in batches limited output and cost more fuel and labor.
How it works
Coffey's still has two tall columns. Fermented wash flows continuously down over a series of plates while steam rises to meet it and strips out the alcohol, whose vapor passes to a rectifier and is condensed. It forms a closed system that runs without interruption. It yields a light spirit of high strength quickly and with less fuel and labor than a pot still, and can use practically any grain. It removes most of the oils and flavor compounds of the grain.
Who pushed back
Irish distillers favored the traditional pot still and at first rejected the lighter spirit that the Coffey still produced. Scottish distillers took it up instead. The Excise approved the still in 1832 after tests at the Dock distillery and at another Dublin distillery owned by the Haig family.
What lasted
The Coffey still became the standard for making grain whisky, the base of blended Scotch whisky, and modern column stills are not far removed from the original design. Most distilled alcohol, whether whisky, rum, vodka or gin, is now made in such stills. The sources note that his contribution is little recognized in Ireland.
