Distillation Process
Part of Alcohol and Distillation
The complete distillation process from heating the wash to collecting purified alcohol.
Why This Matters
Fermentation alone can only produce liquids up to about 15-18% alcohol by volume. Beyond that concentration, the yeast dies in its own waste product. Distillation is the process that takes this weak alcoholic wash and concentrates it to 40%, 60%, 80%, or even higher purities. This concentrated alcohol is essential not just for drinking spirits but for medicine, fuel, solvents, and preservation.
Understanding the full distillation process, not just the equipment but the sequence of steps, temperatures, timing, and decision points, is what separates safe, effective distillation from dangerous waste. A poorly run still produces toxic methanol-contaminated spirits, wastes fuel, and can even explode. A well-run still produces clean, safe product efficiently.
This article covers the entire process from start to finish: preparing the still, heating the wash, managing temperatures, collecting fractions, and cleaning up. Master this sequence and you can distill anything from grain whiskey to purified water to essential oils.
Preparing for a Run
Before applying any heat, complete these preparation steps:
Charge the Still
Pour your fermented wash into the pot (boiler) of the still. Filter out large solids first through a cloth or mesh strainer. Solids scorch on the bottom of the pot, creating off-flavors and potentially blocking vapor flow.
Fill the pot no more than 75% full. The remaining headspace allows for foaming and prevents liquid from being pushed up into the column or lyne arm (a phenomenon called “puking” that contaminates your distillate with unfermented wash).
Check All Seals
Inspect every joint, connection, and seal in the still. Vapor leaks waste product and create fire hazards. Traditional sealants include:
- Flour paste: Mix flour and water into a thick paste. Apply around joints. It hardens with heat and peels off when cool.
- Rye dough: Similar to flour paste but more pliable. Traditional in European distilling.
- Wet cloth strips: Wrap dampened cotton or linen around joints. Works temporarily but must be re-wetted during long runs.
Prepare the Condenser
Fill the cooling water jacket or start the flow of cooling water. The condenser must be cold before vapor reaches it. If using a static water bath, have additional cold water standing by for replacement.
Set Up Collection Vessels
You will need at least three separate containers for collecting different fractions:
- Foreshots/heads jar (small, 200-500ml)
- Hearts container (your main collection vessel)
- Tails container (medium, 1-2 liters)
Label them clearly. Have a way to quickly switch between containers, such as a funnel that can be moved from one jar to another.
The Heating Phase
Starting Heat
Apply heat to the pot gradually. Rapid heating causes uneven boiling, foaming, and difficulty controlling the process. If using a wood fire, start with a moderate fire and increase as needed. If using a gas or alcohol burner, begin at medium heat.
Critical Temperatures
Understanding the boiling points of key compounds is essential:
| Compound | Boiling Point | Status |
|---|---|---|
| Acetone | 56.2C | Discard (foreshots) |
| Methanol | 64.7C | Discard (foreshots) |
| Ethyl acetate | 77.1C | Discard (heads) |
| Ethanol | 78.3C | Collect (hearts) |
| Water | 100C | Dilutes product |
| Fusel alcohols | 100-140C | Discard (tails) |
Methanol Danger
Methanol is produced in small quantities during all fermentation. It causes blindness and death even in small doses. The foreshots fraction concentrates methanol and must ALWAYS be discarded. Never skip this step.
Temperature Monitoring
A thermometer at the top of the column or in the vapor space of the pot is invaluable. Without one, you must rely on timing and sensory evaluation (smell, taste of small samples, rate of drip).
As the wash heats, the temperature rises steadily until it approaches 78C. At this point, you will see the first drops of liquid emerging from the condenser. The temperature may plateau briefly as the lightest compounds boil off.
Collecting Fractions
Foreshots (First 50-100ml)
The very first liquid to emerge from the condenser contains the highest concentration of methanol, acetone, and other volatile toxins. For a typical 20-liter wash, discard the first 50-100ml (roughly the first 30-60 minutes of very slow dripping).
Foreshots smell harsh, sharp, and chemically. There is no ambiguity: they smell wrong. Discard them or save them for use as solvent or fire starter. Never drink foreshots under any circumstances.
Heads (Next 200-500ml)
After the foreshots, the distillate transitions to the heads fraction. Heads contain ethanol mixed with lighter alcohols and esters. They have a sharp, solvent-like smell that gradually softens.
The heads fraction is not dangerous in the way foreshots are, but it contributes harsh flavors and headache-inducing compounds. Experienced distillers save heads and add them back to the next batch’s wash for redistillation, recovering the ethanol they contain.
Hearts (The Main Collection)
The hearts fraction is your target product. It begins when the distillate smells clean, smooth, and pleasant, with the characteristic warmth of ethanol and none of the sharpness of heads.
Signs you have reached the hearts:
- Smell: Clean, smooth, warm. If making fruit brandy, you may detect fruit aromatics.
- Taste: A tiny drop on the tongue burns cleanly without harshness or bitterness.
- Temperature: Column temperature stabilizes around 78-82C.
- Flow rate: Steady, consistent dripping (aim for 2-4 drops per second for quality; faster risks pulling over impurities).
Continue collecting hearts as long as the distillate remains clean-tasting and the column temperature stays below about 85-88C.
Tails
As the ethanol in the wash depletes, the column temperature rises and heavier compounds begin to come over. The tails fraction is characterized by:
- Smell: Wet cardboard, oily, musty
- Taste: Harsh, bitter, oily
- Appearance: May appear slightly cloudy
- Temperature: Column temperature climbs above 90C
Stop collecting hearts and switch to the tails container. Tails contain water, fusel oils, and other heavy compounds. Like heads, they can be saved and added to the next batch for redistillation.
Managing the Run
Heat Control
The single most important skill in distillation is heat management. Too much heat causes:
- Rapid boiling that carries liquid droplets into the vapor (reduces purity)
- Difficulty separating fractions (everything blurs together)
- Risk of scorching if the pot runs low
Too little heat causes:
- Extremely slow output (wasted fuel and time)
- Poor separation in some still designs
Aim for a steady, moderate output rate. For a small pot still (20-50 liters), 2-4 drops per second from the condenser is a good target. Adjust heat to maintain this rate.
The Parrot and Proofing
A “parrot” is a small glass or clear container that the distillate flows through on its way to the collection vessel. It allows you to continuously monitor the proof (alcohol concentration) of the output.
Without a hydrometer, you can estimate proof by:
- Shake test: Collect a small sample in a jar and shake vigorously. High-proof spirits produce small, persistent bubbles. Low-proof spirits produce large bubbles that pop quickly.
- Burn test: Dip a spoon in the distillate and ignite it. Spirits above 50% ABV burn with a steady blue flame. Below 40%, they struggle to sustain flame.
When to Stop
End the distillation run when:
- Column temperature exceeds 95C (mostly water coming over)
- The distillate no longer burns when ignited
- The output tastes predominantly of water with unpleasant oily notes
- You have collected the expected volume of product
A 20-liter wash at 10% ABV contains 2 liters of pure alcohol. Accounting for losses, expect to collect 2-3 liters of hearts at 50-65% ABV from a single run.
After the Run
Shut Down
- Remove heat source from the still.
- Allow the system to cool before disassembling. Opening a hot still releases scalding steam.
- Drain and discard the spent wash (called “pot ale” or “dunder”). This can be composted or used as animal feed supplement.
Clean the Equipment
Rinse the pot, column, and condenser with hot water immediately after each run. Residual wash left in equipment promotes bacterial growth and off-flavors in subsequent batches.
Periodically deep-clean copper components with a vinegar and salt solution to remove tarnish and verdigris. Rinse thoroughly with clean water afterward.
Process the Distillate
Your collected hearts may be:
- Diluted to drinking strength (40-50% ABV) by adding clean water
- Aged in oak or other wood containers for flavor development
- Redistilled for higher purity (see Multiple Runs)
- Used as-is for fuel, medicine, or solvent
Always label containers with the date, source material, proof, and whether it is hearts, heads, or tails. Good record-keeping is essential for consistency and safety.
Common Problems and Solutions
Cloudy distillate: Usually caused by too-rapid distillation pulling over liquid. Reduce heat. Can also indicate fusel oils, especially if cloudiness appears when diluted with water (the “louche” effect).
Low yield: Check for vapor leaks. Ensure the wash was fully fermented before distilling. Verify condenser is adequately cooled.
Scorched taste: Solids in the pot are burning. Strain wash more thoroughly before charging. Use a double-boiler or bain-marie setup for delicate washes.
Still “puking”: Wash is foaming up into the column. Reduce heat immediately. Next time, fill the pot to only 60% capacity. Anti-foaming agents (a drop of vegetable oil) can help.
Inconsistent drip rate: Heat input is fluctuating. Stabilize your fire or burner. With wood fires, maintain a bed of coals and add small amounts of fuel frequently rather than large additions.