Distillation
Distillation is the thermal separation process used to produce spirits by heating a fermented liquid to vaporize alcohol, then condensing the vapor to create a concentrated alcoholic product with higher proof than the original fermentation.
In Plain English
Distillation is the core process that makes spirits different from beer and wine. After grains, fruit, or sugar are fermented into a low-proof alcoholic liquid (like a beer or wine), that liquid is heated in a still. Alcohol vaporizes at a lower temperature than water, so the vapor is richer in alcohol than the original liquid. The vapor is cooled back into liquid, producing a spirit with much higher alcohol content. Different still types produce different flavor profiles: pot stills (used for whiskey, brandy, and many craft spirits) retain more flavor compounds, while column stills (used for vodka, gin, and large-scale production) produce cleaner, higher-proof distillate. The distiller's skill lies in managing the cuts — separating the desirable middle portion of the distillation run from the undesirable heads and tails.
Technical Detail
Distillation operates on the principle of differential boiling points: ethanol boils at 78.37°C versus water at 100°C. In practice, the distillate contains both ethanol and water in varying proportions depending on the still design and operation. Pot stills (batch distillation) produce distillate in a range of 60-85% ABV in a single pass and retain significant congeners (flavor compounds). Column stills (continuous distillation) can produce distillate above 95% ABV with minimal congeners. The TTB regulates maximum distillation proof by product type: bourbon/rye whisky must be distilled at ≤160 proof (80% ABV), brandy at ≤170 proof, and vodka must be distilled at ≥190 proof. These limits are set in the standards of identity (27 CFR 5.22) and directly affect the character of the final product. The heads (first fraction, high in methanol and acetone) and tails (last fraction, high in fusel oils) are separated from the hearts (middle fraction) through skilled cutting.
Why It Matters
Distillation is the defining process for the entire spirits industry. For equipment manufacturers, understanding distillation methods and trends drives product development and sales. For consultants, advising on still selection, distillation parameters, and process optimization is a specialized service. The choice of distillation method affects COLA classification because the maximum distillation proof limits determine which standards of identity a product can meet.
Related Terms
Frequently Asked Questions
What is the difference between a pot still and a column still?
Pot stills operate in batches and produce lower-proof distillate with more flavor congeners, preferred for whiskey and brandy. Column stills run continuously and produce higher-proof, cleaner distillate, preferred for vodka and neutral spirits. Some distillers use hybrid systems combining elements of both.
Can you distill alcohol at home?
Federal law prohibits distilling spirits at home without a DSP permit, regardless of the quantity or intended use. This differs from home brewing of beer and wine, which is permitted up to certain volumes. The prohibition is primarily a tax issue, as spirits are subject to federal excise tax.
How many times is a spirit typically distilled?
It varies by product type and producer. Many pot-still whiskeys are double-distilled (some Irish whiskeys are triple-distilled). Vodkas may be distilled multiple times or pass through a column still with many theoretical plates. The number of distillations affects purity and flavor character.