Bartender Basics

From commercial vodka to cult bourbon, all spirits are distilled. It’s a scientific and often creative process that transforms harsh ethanol into something safely potable and, if you’re lucky, downright delicious. But when it comes to distilling, methods vary. The two most common types of distillation are named after the machinery involved: pot and column stills. The differences between pot and column distilling include equipment, efficiency and output. Whether one approach is inherently better than the other is up for debate, and professional distillers say nuance is key. Here is a quick guide to understanding how pot and column distilling work to make your favorite spirits. How Does Distilling Work? Any liquid can be distilled. For example, to distill water, you pour it into a container with a lid, heat it until the water becomes steam and then cool and collect the condensed vapor so it turns back into liquid. The resulting distilled water contains none of the original impurities or minerals. It’s slightly more complicated to distill a mixture of liquids that have different chemical structures, like combining water and ethanol to distill into liquor. Ethanol is more volatile and has a higher vapor pressure than water, so it transforms into steam faster. Distillers must calibrate these components as they create the flavors, textures and proofs of their desired spirits. That’s where pot and column distilling, along with other types of stills come into play. What Is Pot Distillation? Pot stills are ancient. Archeologists discovered an early iteration at Tepe Gawra (5000-1500 B.C.E.), a Mesopotamian settlement located in modern-day Iraq. A modern pot still consists of a tub-like base surrounded by a heat source such as a flame, steam jacket or electric coils. Often made of copper, the tub connects to an elongated tube, sometimes called a swan neck. Additionally, it connects to a condenser and some sort of receptacle you might hear referred to as a basin, parrot or spirit safe. To use a pot still, distillers pour their liquid into the tub and heat it. After it turns into vapor, it rises through the swan neck and meets the condenser. There, a coolant lowers the temperature, and the steam condenses back into liquid that collects in the basin. This process is usually repeated multiple times to attain proof and palatability. As a result, pot stills are often used by small and craft operations, particularly those that specialize in richly flavored spirits like Scotch, Irish whiskey, Cognac and tequila. “A pot still gives you all those rich cereal flavors and esters that taste almost fruity,” says Isaac Winter, the blending and distilling manager at High West Distillery in Utah. “The distillate tends to be heavier, too.” Joe O’Sullivan, a master distiller at Clear Creek and Hood River Distillers, both in Oregon, compares pot still distillation to a piece of handmade furniture. “It may have imperfections, but it’s loaded with character.” What Is Column Distillation? Also called continuous, patent or Coffey stills, column stills were developed in the early 19th century. They use the same principles of vapor creation and collection as pot stills, but the machinery looks and functions differently. Rather than a squat tub, there’s an upright pillar that might be made of copper or a combination of stainless steel and copper. It contains several layers of perforated plates, around which vapor condenses and pools. “A column still acts like a series of pot stills placed on top of each other, with the liquids vaporizing and condensing over and over again on each tray inside the column,” writes Nicole Austin in The Oxford Companion to Spirits & Cocktails. Because the liquid is continuously vaporizing and condensing in the column, this method tends to be quicker and more hands-off than in a pot still. It’s an especially effective way to make spirits like vodka since the machine can essentially whittle down the base mixture to its most neutral essence, says O’Sullivan. “But that’s not to say craft whiskey can’t be made on a column still, because it definitely can," he notes. The Difference Between Pot and Column Distillation Pot stills aren’t better than column stills, they simply serve different purposes. If you want to create a neutral spirit quickly and consistently, a column still will serve you best. If you aim to create something distinctive with a heavier texture, go with a pot still. To do the latter at scale, you might prefer a hybrid still, which combines a tub-like base beneath a tower that functions similarly to a column still. But, there’s no one-size-fits-all approach to distillation, says O’Sullivan. “I’ve had some really terrible products made on pot stills and I’ve had wonderful products made on column stills.” Ultimately, it all depends on the distiller, their materials and what they’re best at using. “We need to stop assigning value to the tool and recognize what the tool can do for us,” he adds. “Some people can sculpt with a chainsaw and some can sculpt with a scalpel.”