Running the Still: Heads, Hearts, Tails
Reminder before this chapter: home distillation has no federal personal-use exemption in the United States. This chapter describes how a distillation run works as a matter of chemistry and process. It isn't legal advice and it isn't a workaround. Check your local, state, and federal rules before you build or run anything.
Chapter 2 ended with a finished, settled wash. This chapter covers what happens when that wash meets heat. The short version: a still doesn't produce one liquid, it produces a sequence of them, and the skill in distilling is deciding which parts of that sequence to keep.
Safety Comes Before Chemistry
A run involves a heated vessel, flammable vapor, and high-proof liquid collecting in the open. The failures that hurt people aren't exotic. They're the same handful every time:
- A still is never sealed. The vapor path from boiler to condenser output stays open to the air the entire run. A blocked or clamped-shut path lets pressure build in a hot vessel, and that's how boilers fail violently.
- Ethanol vapor is flammable, and it's heavier than air. Vapor that escapes a leaking joint or an undersized condenser pools low and travels. Open flame near the collection point and poor ventilation are the two conditions behind most still fires.
- Condenser cooling runs before the heat does, and stays on until the run is over. Losing cooling mid-run turns the output into uncondensed vapor.
- Runs are attended. The whole run, start to finish.
- Leaks get found before the run, not during it. Distillers commonly check joints with water in the boiler first.
None of this is optional reading. The rest of the chapter assumes it.
Why Distillation Separates Anything
Every compound in a wash has its own boiling point. Ethanol boils at about 173°F (78.4°C), water at 212°F (100°C), and the trace compounds from fermentation are spread on either side of ethanol. When a wash is heated, the vapor coming off is richer in whatever boils easiest at that moment. As the run goes on, the easiest-boiling compounds get used up, the temperature at the still head climbs, and the vapor's makeup shifts.
That shift is the whole game. The output at the start of a run and the output near the end come from the same wash but taste, smell, and measure completely differently. Distillers split that stream into four parts.
The Four Fractions
Foreshots. The first small amount off the still. Rich in the most volatile compounds: acetone, acetaldehyde, ethyl acetate. It smells sharp and solvent-like, closer to nail polish remover than to anything drinkable. Distillers discard foreshots as standard practice, every run, without exception.
Heads. Still volatile, still harsh, but increasingly ethanol. Heads carry solvent and fruity-sharp notes that fade as the run moves forward. They aren't kept in the final spirit, but they're often saved for a later run rather than thrown out.
Hearts. The part worth keeping. Clean, smooth, mostly ethanol and water, with the wash's character in balance. Everything upstream of this point in the guide exists to make the hearts better.
Tails. As the ethanol in the boiler runs low, heavier compounds start coming through: fusel oils, fatty acids, a wet-cardboard or wet-dog smell, an oily feel. Proof at the output drops steadily. Like heads, tails are usually saved and added to a later run, where the ethanol they still contain can be recovered.
The Methanol Question
Methanol is the concern everyone has heard about, and most of what gets repeated about it is wrong in one direction or the other.
Methanol boils lower than ethanol, which is why it's often described as "coming out first." It doesn't, cleanly. Methanol mixes completely with water and ethanol, and in a real run it's spread across the whole output rather than stacked at the front. Discarding the foreshots removes the most volatile compounds, but it isn't what controls methanol.
What controls methanol is the wash. Methanol comes mostly from pectin, the structural material in fruit. A sugar wash or a grain mash produces little. A fruit wash produces more, which is why chapter 2 flagged it. In practice, that means the methanol question gets answered at the fermenter, and conservative cuts are the second layer of margin on top of it, not the first.
Stripping Runs and Spirit Runs
Many distillers split the work into two passes:
- The stripping run is fast and makes no cuts beyond discarding foreshots. Its job is to pull as much alcohol out of the wash as possible. The result, called low wines, is a rough, lower-proof distillate with most of the wash's water left behind.
- The spirit run redistills the collected low wines slowly, and this is where the heads, hearts, and tails get separated with care.
Splitting the work this way means the careful, slow run happens on a smaller volume that's already concentrated, which makes the cuts easier to see and the run shorter. Reflux stills (chapter 1) do much of that separation inside the column in a single pass, which is part of why they suit neutral spirits.
Making Cuts
A cut is the point where the output switches from one fraction to the next. There's no single number that marks it. Thermometers, hydrometers, and your nose all feed into it:
- Temperature at the still head tells you roughly where you are in the run. On a pot still it climbs steadily. On a reflux still it holds steady through the hearts and moves when the run changes.
- Proof at the output falls through the run. Tracking it tells you how fast you're moving toward tails. Alcohol hydrometers are calibrated at a set temperature (printed on the hydrometer, commonly 60°F / 15.6°C or 68°F / 20°C), so a reading from warm distillate needs a temperature correction to be accurate. The Convert tab on our calculators handles the °F/°C side of that.
- Smell and taste are what experienced distillers trust most for the actual cut decision. Numbers tell you when to start paying attention. Your senses tell you where the line is.
Collecting in Jars
The most reliable technique for a new distiller isn't a better thermometer. It's small jars.
Instead of collecting the run in one vessel and guessing when to switch, distillers collect it in a numbered series of small jars, one after another, from the end of the foreshots to the end of the run. Each jar is a snapshot of one moment. Once the run is over, the jars get left loosely covered to air out, often overnight, and then evaluated side by side the next day: smell each one, dilute a small sample and taste it, and decide which jars join the hearts.
This does two things. It takes the cut decision out of the heat of the moment, and it turns every run into a record. Jar 14 was the last good one this time? That's a data point for next time.
Feints and Recycling
Heads and tails from the spirit run, together called feints, still carry usable ethanol. Many distillers save them and add them to the boiler on a later run. Over time this recovers alcohol that would otherwise be lost, and some styles of spirit build part of their character this way.
Keep a Log
Same advice as chapter 2, for the same reason. Date, wash, volume in the boiler, heat setting, head temperature at key points, proof per jar, which jars made the cut, final volume and ABV. The Yield tab on our calculators estimates what a wash should produce; the log tells you what it did. The gap between the two is where the learning is.
What's Next
The hearts coming off the still are high-proof and raw. The next chapter covers proofing and blending: bringing a spirit down to drinking strength accurately, why water gets added slowly, and how batches get combined to hit a target.
In the US, federal law bans distilling spirits at home, and the Supreme Court is reviewing that ban (DOJ v. McNutt). State and local rules apply too. This content is for informational and educational purposes only and is not legal advice. Calculator outputs are planning estimates, not lab measurements. Read our full Legal Disclaimer for more detail.
A federal appeals court ruling in April 2026 changed part of this picture in three states — see our full breakdown before assuming anything here is settled.