There’s a lot of attention paid to the way that whiskey is aged. Talk to even a casual whiskey drinker and he or she will likely be able to drop some barrel factoids on you. Yet, the apparatus that is actually responsible for making that spirit, the whiskey stills, are often an area of mystery.
Pot Stills vs. Column Stills
The obvious starting point in any discussion of whiskey distillation is pot stills versus column stills. A pot still at its simplest consists of a large kettle or pot which is heated from the bottom, boiling off the alcohol and allowing the vapors to be sent to a condenser and separated.
With column distillation, the mash enters near the top of the still and begins flowing downward. This brings it closer to the heating source, and once it’s heated enough to evaporate, the vapor rises up through a series of partitions known as plates or stripping plates. At each platealong the way, the vapor ends up leaving behind some of its heavier compounds and cogeners.
The most important point of difference between pot stills and column stills is that pot stills operate on a batch by batch basis, while column stills may be operated continuously. This is why they’re sometimes known as continuous stills. Further, column stills that are rigged to do so can produce spirit over 95% ABV, nearly pure ethanol, whereas pot stills cannot achieve such returns.
It should also be noted that while most pot stills are made entirely from copper, in some instances, column stills will be part stainless steel. Here, only the upper portion of the still which actually comes into contact with the alcohol vapor will be copper, which is important as copper is utilized to help rid the spirit of sulfur.
Many of America’s craft distilleries today use what’s essentially a hybrid pot still. It has a pot still at its base but also one or more columns, allowing a distillery the flexibility to produce different types of spirits and to control the specifics of distillation along the way.
History & Modern Production
What about Coffey stills and patent stills? Whether you call it a column still, continuous still, Coffey still, or patent still, you’re basically talking about the same thing.
Irishman Aeneas Coffey patented his column still design in 1830, building upon the design of Scotsman Robert Stein from several years prior, which itself built upon a number of previous continuous distillation column designs. All the new designs along the way essentially offered increased efficiency, allowing distillers to distill to higher proofs in single runs. It was Coffey’s design that would truly transform whiskey production and be utilized across the globe.
If you need to acquire a new whiskey still today, who’s making it for you? A few names may be familiar. There’s Forsyths, in Scotland; Vendome, based in Louisville, Kentucky; Kothe, a German company (whose American wing was actually founded by the couple behind Koval who has helped to train and set up numerous American craft distilleries); CARL, another German manufacturer; and also the Italian company Frilli, amongst others.
Today’s stills have come a long way, of course. They’re highly advanced, and at large facilities are typically computer controlled and monitored. Some even come with smartphone apps. For instance, at Washington, D.C.’s One Eight Distilling, their hybrid pot still can be controlled with an app, allowing their team to fire it up remotely before even stepping through the doors. They actually bought their hybrid from Koval, after the Chicago distiller outgrew it.
Still Specifications & Differences
Even stills of the same type vary greatly. Overall size and capacity of the still; shape of the kettle; length, shape and angle of components such as the neck and line arm; whether or not there are any reflux bowls or bubbles above the main kettle; heating sources; and in the cases of columns, how many plates it has, and whether those plates have bubble caps.
The exact specifications of a company’s stills and the precise new make spirit which it churns out are key to any brand’s flavor profile. That’s why when long-established distilleries expand production, they don’t invest in new, larger stills; they invest in replica copies of their current stills. This increases production quantity but never alters the specific quality of the spirit which results.
For instance, the Macallan touts their “curiously small stills.” At 3,900 liters, they are indeed more appropriately sized for a large craft distillery than a globally recognized brand. But they have 14 of them firing away together, with more en route by 2017. They believe the shape offers rich, fruity characteristics.
Glenmorangie, on the other hand, has the tallest stills in Scotland, with long necks measuring nearly 17 feet high. They tout that only the lightest and purest vapors make it all the way up and out. In between, stills come in all manners of shapes with different characteristics and features.
Compare those 3,900 liter stills at the Macallan to the 80,000 liter behemoths at the Midleton Distillery, where Jameson and a range of other Irish brands are produced. The Midleton stills are the largest operational pot stills in the world, and they’re actually tiny in comparison to the largest pot stills ever made: the 140,000 liter stills used at Midleton in the past. A new set of three stills is on the way, which would increase their total to 10, all also exactly the same.
Distillation Styles & Practices Across the Globe
One leading misconception about distillation is that Scotch must be distilled twice, and that Irish whiskey must be distilled three times. The truth is that while both are norms, neither is a mandate, and there are exceptions to the rule. For instance, the Cooley Distillery in Ireland practices double distillation, not triple. In Scotland, a few distilleries actually triple distill their Scotch, including Auchentoshan.
Further, the grain whisky used in Scotch blends, or the growing number of Scotch grain whiskies, is produced with column distillation. The same goes in Ireland. Remember, though, that “grain whisky” simply refers to whisky that isn’t entirely made from malted barley. In Scotland and Ireland, it’s almost always essentially corn whisky, with a predominantly corn-based mash bill backed up by some level of malted barley.
The defined category of “single pot still Irish whiskey,” on the other hand, is a combination of malted and unmalted barley. While pot still is in that definition, it’s truly the mash bill which defines the category, not the process. Producers are actually allowed to include a certain amount of column distilled whiskey in a single pot still Irish whiskey.
Confused? Things are just as murky with our friends up north, where Canadian “rye whisky” may or may not qualify as rye whiskey in America, with 51% rye in the mash bill. It may not even have any rye whiskey at all.
Once again though, it’s the style of production which becomes a defining characteristic. As just one example, take the case of the new Crown Royal Cornerstone Blend, in which one of its three components is described as a “Coffey rye,” and another as “bourbon style,” yet they share a 60% corn, 36% rye, and 4% malted barley mash bill. Neither is a “rye whiskey” according to American regulation. The Coffey rye is one of Crown’s prized flavoring whiskies, made for just one month of the year and offering a highly creamy character, and the resulting whiskey is characterized by the Coffey still used to make it.
Japan uses yet another approach. Whereas Scotch blends may use stock be sourced from dozens of different distilleries, Japan follows different protocols. There, companies like Suntory produce their own blends by housing numerous whiskey stills of assorted shapes, sizes and styles all in the same facility. In tandem with different yeast strains and fermentation lengths, and assorted barrels, Suntory is capable of making over a hundred of their own different malt whiskies.
Back to bourbon, there remains some confusion about how it’s distilled. Large producers today most commonly follow a system where the first distillation is performed with a column still. The distillate is then transferred to a doubler, which is essentially just an attached, continuous pot still, for a second distillation run.
Massive brands have correspondingly massive column stills at their disposal. The main column still at Wild Turkey is 52-feet tall, with a 5-foot diameter and 19 stripping plates. The Maker’s Mark stills are 45-feet tall with 3-foot diameters and 17 plates. At the Jim Beam American Stillhouse, they have a six-story column still which is capable of having 200 gallons of mash per minute sent into it when it’s firing away.
Again though, while the column distillation and doubler setup is a norm for most large bourbon producers, it’s not a mandate. Look no further than Woodford Reserve, which uses an Irish-style pot still setup and triple distillation.
So is any one type of still, or shape of still, definitively better than the others? That depends on whether you’re asking someone from Kentucky, Scotland, Ireland, Japan, or beyond, and which brand that person either represents or most enjoys drinking. It’s a debate best done over a few drams.
Jake Emen is a freelance writer based in San Diego, and a lover of all types of whiskey. He's passionate about food, drink and travel, and lucky enough to write on such topics as he explores both newly burgeoning regions around the United States, and others across the globe. For...