The Column Still is a modern evolution of the older Pot Still. Column Stills give the users better control over the whole process. Many distillers choose to use these stills over the older Pot Stills because, with a few minor changes to a Column Still, one can create a variety of different spirits.
A Little History
The Column Still is a type of distillation apparatus used to separate two liquids, in this case alcohol from a fermentation, through boiling. Column Stills are generally made with a mix of stainless steel and copper.
Various advances in distillation methods and equipment, from as far back as 1553, would come together to form the column still. However, a clear picture begins to form in 1822 when Sir Anthony Perrier patented one of Europe's first continuous stills in Cork, Ireland. This still allowed the ferment to flow gradually and continuously over the heat, via various partitions. Because small portions of the ferment were heated separately and thus more efficiently, the amount of drinkable alcohol increased.
In 1828, a Scotsman by the name of Robert Stein was inspired by Perrier’s design and aimed to improve on it. He did this by placing the partitions of Perrier’s still into a column, the ferment was then fed into these partitions and heated. He called it a “patent still” and had achieved a similar result to Perrier, but in a more compact form. After numerous demonstrations in the British Isles and Europe, Stein failed to get any significant funding for his venture. He did, however, attract the attention of one man, Aeneas Coffey.
Coffey was an Irish excise tax collector, having observed various stills through his 25 years of work, he recognised the potential in Stein’s design. He also recognised a flaw, to achieve a higher strength alcohol, the individual sections had to be switched out so multiple distillations could take place in one run. Coffey installed two pipes into Stein’s still design, this allowed a greater amount of the vapours to recirculate, eliminating the need for multi-distillation. The resulting spirit was of a much higher alcohol strength and with a lighter character. Shortly after this discovery, in 1830 he was granted patent #5974 for his design.
Distilleries around the world quickly discovered Coffey’s still increased output and produced a spirit with greater smoothness and palatability. Within 5 years of receiving his patent, Coffey had so many orders for his still that he established Aeneas Coffey & Sons in London, a company which is still in operation today as John Dore & Co Limited.
How It Works
A modern Column Still at its most basic level is a heated pot with a column on top and a condenser to the side. This column is divided into sections, very often with copper bubble plates as the separators. These bubble plates allow alcohol vapour to flow up into a section and also allows condensed alcohol to flow down to a lower section when that section, has filled up.
Once the fermentation in the pot has reached the correct heat, the alcohol in it will turn to vapour. This vapour then comes into contact with the bottom of the first bubble plate which will be cooler than the alcohol, causing it to condense. Eventually, this process will cause the first bubble plate to reach a high enough temperature for the vapour to move up into the first section. This vapour will now come into contact with the bottom of the next sections bubble plate, causing it to once again condense. The first bubble plate will over time reach a temperature high enough to boil the currently condensed alcohol in that section, turning it into vapour.
This process will repeat until the vapour moves up through all the sections in the column and over the bend into the condenser, after which it can be collected. Each cycle of evaporation and condensation in a section is in essence one distillation of that alcohol. So, the final alcohol coming out of a column still is, in fact, many times distilled. This is why column stills produce alcohol that is so smooth and palatable.
The draw back of a column still however is that the more sections placed in the column, the more flavour is lost to the process as the alcohol becomes purer and purer. This is where skill and practice come into play for distillers using column stills, figuring out the right amount of sections to use for your product is vital. As an example, Vodka distillers will tend to use more sections, whereas a Whisky distiller will use less. This versatility is why column stills are so popular with craft distillers, allowing one small distillery to produce many different products.
In the end, our aim as distillers is to create a great tasting spirit, and while very important, the still type you choose isn't the only factor that determines if your product is good or not. Thus, it is not a debate between which is better, pot still or column still, but a decision about which works best for you and the spirit you are aiming to create.
This post is intended as a general overview of Column Distillation. The information about various Column Stills and their configurations could easily fill a book and that is not our aim.