What Do Alcohol Stills Do?

If you drink, you know what stills make. Whiskey, rum, vodka, gin, tequila, etc.—all of them are distilled. Though the results might be familiar, how they’re produced might not be.

Distilled Knowledge

At its heart, distillation is one of the most common ways to purify liquids, by separating them into their individual parts. Here, a fermented mixture made from the spirit's component parts (sugarcane or sugar for rum, grain for whiskey, agave for tequila) is separated by heat into alcohol and water.

As the fermented liquid is heated, the vapor that’s produced rises from the base and into a specially cooled copper column. The temperature is regulated so that most of the vapor falls back down into the pot. But the vapor with the highest alcohol content and lowest boiling point will rise through the opening at the top of the still, through the lyne arm and into a water-cooled chamber.

Here, the vapor condenses and drips into a collection chamber. However, the first part of the run, known as the head, contains a lot of volatile chemical compounds called cogeners. The heart, or middle part, is safe for consumption and is separated immediately. The end, or tails, is low proof and is often portioned off to be redistilled later.

Still Making Stills

Clair McLafferty

Most booze is made with a stainless steel, copper, silicon bronze, or brass still. Within the world of whiskey making, copper is king. Though it’s expensive to import the good stuff, copper is easy to form by hand and distributes heat evenly, and it reacts with sulfur in the distillate, says Vendome Copper & Brass Works Inc. Vice President Rob Sherman.

These attributes are important because evenly conducting heat results in an even distillation. During fermentation, yeasts produce sulfur compounds that can add unwanted bitterness to a spirit’s taste profile. But copper binds to these compounds, producing hydrogen sulfide and then copper sulfate. This chemical sticks to the still’s walls and is left behind as the spirit is distilled.

To produce a still, Vendome Copper designs it according to the distillery’s available space and the amount of production they expect. According to Sherman, about 95 percent of the new orders are going out to people who want to make bourbon and whiskey. The orders they receive from more established companies will be for replacement equipment rather than new designs. “If you change your still, you change your product,” says Sherman.

Every still is handmade, and takes between two and three weeks to assemble. Once it’s finished, “everything is broken down and unbolted and put into crates” before it's shipped and reassembled.

But as state laws change to make spirit production and sales easier, the demand has risen and will probably continue to rise. Right now, Vendome is operating on a 6-9 month delay. “As the laws change, we get hundreds of calls,” says Sherman. “If you go into a distillery, you’ll see that most of them use copper."