Distilled, when applied to alcohol, means the liquid has been heated to separate ethanol from water and other substances, then collected as a more concentrated spirit. Fermentation alone produces drinks like beer and wine with roughly 5% to 15% alcohol by volume. Distillation takes that fermented liquid and pushes the alcohol concentration much higher, which is how spirits like whiskey, vodka, rum, and gin are made.
How Distillation Actually Works
The process relies on a simple physical fact: ethanol boils at 78°C (about 172°F), while water boils at 100°C (212°F). When you heat a fermented liquid, the alcohol vaporizes first. That vapor rises, gets collected, and cools back into a liquid in a separate container. What you’re left with is a spirit that has a much higher percentage of alcohol than the original fermented “wash” or “mash” it came from.
There is a natural ceiling to how pure the separation can get. Ethanol and water form what chemists call an azeotrope at 96% ethanol and 4% water, meaning at that ratio they boil together and can’t be separated any further by simple distillation alone. In practice, most spirits are distilled well below that point and then diluted with water to reach their target strength before bottling.
Distilled Spirits vs. Fermented Drinks
Every alcoholic beverage starts with fermentation. Yeast eats sugar and produces ethanol and carbon dioxide. Beer, wine, cider, and sake stop there. The yeast eventually dies off as the alcohol concentration rises, which is why fermented drinks top out around 15% ABV in most cases.
Distilled spirits pick up where fermentation leaves off. The fermented liquid is essentially the raw material. Whiskey starts as something like a beer. Brandy starts as wine. Rum starts as fermented sugarcane juice or molasses. The distillation step is what transforms these into spirits, concentrating the alcohol and selectively carrying over (or leaving behind) flavor compounds.
Pot Stills vs. Column Stills
There are two main types of equipment used, and they produce noticeably different results.
Pot stills are the older, simpler design: large copper vessels that are filled, heated, emptied, and filled again for each batch. This slower process retains more of the flavor compounds from the original fermented liquid, producing spirits with rich, intense aromas. Tequila, mezcal, many malt whiskeys, and some Jamaican rums are typically made in pot stills.
Column stills, developed in the 1830s, are tall cylindrical towers with stacked plates inside that create multiple stages of separation. They run continuously rather than in batches, making them far more efficient. They also distill to a higher alcohol content, which strips out more flavor compounds and produces a cleaner, more neutral spirit. Most vodka and many lighter rums and grain whiskeys come from column stills.
Heads, Hearts, and Tails
Not everything that comes out of a still is safe or pleasant to drink. Distillers divide their output into three fractions, called “cuts,” and only keep the middle portion.
- Heads: The first liquid to emerge. It contains the most volatile compounds, including methanol and acetone. These are potentially toxic and taste harsh. Distillers discard them.
- Hearts: The middle cut. This is the clean, desirable spirit with the best balance of flavor and purity. It’s the only portion that ends up in the bottle.
- Tails: The last fraction. It carries heavier compounds called fusel oils that create an oily mouthfeel and off-flavors. Tails are either discarded or redistilled.
Knowing where to make these cuts is one of the core skills of a distiller. In column stills, the separation happens more automatically across the stacked plates. In pot stills, the distiller monitors the output and decides in real time when to switch from heads to hearts to tails, which is part of why pot-distilled spirits vary more from batch to batch.
How Distillation Shapes Flavor
Beyond ethanol, fermented liquids contain hundreds of minor compounds called congeners. These include esters, aldehydes, and organic acids that contribute aroma and taste. The degree of distillation determines how many congeners survive into the final spirit.
A spirit distilled to very high purity, like vodka, has almost no congeners. That’s by design: vodka is often distilled multiple times and then filtered through charcoal to strip away as much character as possible, leaving a clean, neutral taste. Bourbon, on the other hand, is distilled to retain a high level of congeners, which gives it its bold, complex flavor. Research has found that bourbon’s heavy congener load is also associated with more severe hangovers compared to low-congener spirits like vodka.
Gin sits in an interesting middle ground. It starts as a neutral spirit similar to vodka, but is then redistilled with botanicals like juniper berries, citrus peels, herbs, and spices. To legally be called gin, the spirit must be flavored with juniper. London Dry Gin adds all its botanicals before the final distillation. Other styles steep botanicals in the spirit afterward, allowing for bolder or sweeter flavor profiles.
What “Distilled Spirit” Means Legally
In the United States, the federal alcohol regulations define distilled spirits broadly as ethyl alcohol and all dilutions and mixtures of it intended for drinking. The category covers everything from whiskey and rum to brandy, gin, and beyond. Products with less than 0.5% ABV fall outside the definition entirely, and certain low-proof mixtures that are mostly wine are also excluded.
The legal framework matters because it determines labeling, taxation, and how products can be marketed. A beverage that has been through a still is regulated differently than beer or wine, even if the final alcohol content is similar. That’s why you’ll sometimes see “distilled spirit” on labels for products like hard seltzers or canned cocktails: the alcohol inside was produced through distillation, not just fermentation, regardless of the drink’s final strength.