What is pot distillation?

We’ve learned that the first distillation of alcohol was a Muslim discovery, and what is now termed pot distillation was the original method.

Thousands of years ago, pot distillation produced balms, salves, and perfumes. But it wasn’t long before someone put wine in the still, and the world’s first brandy was born. Not only were the wine’s flavors more concentrated, but the alcohol content was higher, and the drink’s shelf stability improved incredibly.

Alright. Let’s take a couple of steps back. What does distillation actually do? Distillation is the process of using heat to separate elements in solution. In layperson’s terms, we’re talking about the simple fact that everything in solution has a vapor point (i.e., boiling point) or temperature at which it will turn into steam. We learned in multiple classes throughout our childhood and teenage years that water boils at 212 degrees Fahrenheit (100 degrees Celsius). This is the most important point.

But many ingredients in a given solution—let’s take wine as an example—have lower vapor points than water. This is convenient because it means that they can effectively be strained out of the water by catching their vapor and then recondensing it into a more purified form. Fortunately, beverage alcohol (ethanol) is one such element that has a lower vapor point than water, which means that we can separate the two.

But why is it called a “pot” still?

It’s called a “pot” still because that’s the basic shape of the device’s main chamber – or at least it used to be. Until the 1800s, we simply called it a “still,” but the invention of the “column” still caused a realignment and new names. Column stills are more efficient at creating pure ethanol, so they have been adopted by the vodka, Korean soju, and grain whisky industries, to name a few.

However, authentic (honkaku) shochu and awamori makers are prohibited from using them. They can only use pot stills, a requirement that has both upsides and downsides.

Column stills, used in Japan’s spirits industry since the early 1900s, create far more alcohol by comparison. This comes at the expense of flavor and aroma. When making vodka or Korean soju (green bottle), the goal is to make a neutral spirit, which is achieved by cyclically heating and cooling the fermented mash inside the still’s main chamber until it’s as divorced from the ingredients used to make it as humanly possible.

Column distillation often results in a spirit in the mid-90s ABV that smells of nearly pure ethanol. Column-distilled spirits are then diluted to bottling proof—around 40% ABV for vodka and high teens for green bottle Korean soju. Sometimes, they end up in a cask. In the case of green-bottle Korean soju, synthetic sweeteners are added before bottling. Vodka is also commonly adulterated, even though this is not typically labeled. Honey and sugar are sometimes used to soften the alcohol burn and provide some mouthfeel, while glycerine is also used to the same effect.

How are shochu and awamori unique?

Single pot distillation

Since pot distillation has the inherent quirk of leaving more flavor and aroma from the fermentation intact, most spirits traditions around the world will do at least two “runs.” In mezcal production, for instance, two runs are required. When the fermented mash is pumped into the still and heated with fire or steam, what comes out of the swan neck, through the condenser, and into a large container is known as a “stripping run.” If the fermentation was rushed, or the ingredients poor, then it’s hoped that the stripping run will help remove some of them alongside a large volume of water.

The distillate is then fed into a pot still a second time for what is known in the industry as the “spirit run.” With each successive run, the spirit tastes and smells less like the ingredients used to make it. Extra distillation simultaneously boosts ethanol isolation, creating a spirit with higher proof. A third distillation run is not uncommon.

But shochu and awamori are different from most spirits. They are only distilled once in a pot still.

This naturally means that Japan’s indigenous spirits will be lower-proof than their counterparts distilled elsewhere in the world. The nation’s tax code enforces this reality, requiring them to be bottled at under 90 proof. If you were hoping for firewater, this isn’t it.

But the inherent beauty in all this is that pot stills are honest. They will reveal the ingredients (good and bad) that spent weeks together during fermentation. Japanese distilleries are keenly aware that a low-quality ferment will taste like garbage after a single run through a pot still, which is why their fermentations are so lengthy, painstaking, and meticulous. A “long” whisky fermentation might last four days; a short shochu fermentation, on the other hand, will easily eclipse two full weeks before it meets the pot still.

Steel rather than copper

A metallic detail that catches many spirits aficionados off guard is the fact that shochu and awamori distilleries don’t use copper stills. They all use stainless steel pot stills. The high acidity levels found in the mash would rapidly degrade copper, and koji-assisted fermentation techniques used in Japan mean that sulfuric compounds aren’t a serious concern anyway.

No additives

One of the coolest things about Japan’s native spirits is that additives are never allowed. Unlabeled additives are surprisingly common in the spirits world. I’m talking boisé extract in Cognac, stevia in Korean soju, and E150A caramel coloring in rum.

Honkaku (authentic) Shochu and Ryukyu Awamori can only be made from approved ingredients (and their koji), water, and yeast. So, if you’re interested in a hangover-resistant sipping experience, give Japan’s traditional spirits a try!