Multiple Runs

Part of Alcohol and Distillation

Increasing alcohol purity and quality through multiple distillation passes.

Why This Matters

A single distillation pass through a simple pot still typically produces spirit at 40-65% ABV. This is adequate for drinking spirits but insufficient for many critical applications. Medical-grade antiseptic needs 60-70% ABV with high purity. Fuel alcohol needs 80-95% for engine use. Solvent alcohol needs the highest purity achievable for dissolving resins and extracting compounds.

Multiple distillation runs are the traditional method for achieving higher purity when you lack a reflux column. Each pass through the still separates alcohol from water and impurities more effectively. Double distillation is standard for most whiskeys. Triple distillation produces the smooth, clean spirits associated with Irish whiskey and premium vodkas. Four or more passes can approach 90-95% ABV.

Understanding multiple runs also improves your ability to produce clean spirits in a single run by teaching you how impurities behave and how each pass changes the composition of your distillate. Even if you choose to do only one run, the knowledge of what a second run would accomplish helps you make better fraction cuts.

Theory of Successive Distillation

Why One Pass Is Not Enough

Ethanol and water form a mixture that does not separate cleanly at any single boiling point. When a 10% ABV wash boils, the vapor is not pure ethanol; it is a mixture of approximately 55-60% ethanol and 40-45% water (plus trace compounds). Condensing this vapor gives you a liquid at 55-60% ABV, a significant concentration but far from pure.

The relationship between liquid composition and vapor composition is described by the vapor-liquid equilibrium curve. At every step, the vapor is enriched in ethanol relative to the liquid, but never completely pure.

Liquid ABV	Vapor ABV (approx.)	Enrichment Factor
5%	35%	7x
10%	55%	5.5x
20%	65%	3.2x
40%	75%	1.9x
60%	82%	1.4x
80%	88%	1.1x
89.4% (azeotrope)	89.4%	1.0x (no further separation)

Notice that the enrichment factor decreases as concentration increases. The first run achieves dramatic concentration. The second run achieves significant further concentration. Each subsequent run achieves less, with diminishing returns.

The Azeotrope Limit

At 89.4% ABV (95.6% by weight), ethanol and water form an azeotrope: a mixture that boils at a constant temperature and produces vapor of the same composition as the liquid. No amount of simple distillation can exceed this concentration.

To go beyond 89.4% ABV requires either:

• Molecular sieves (zeolite minerals that absorb water molecules)
• Azeotrope-breaking agents (adding benzene or cyclohexane, then redistilling)
• Salting out (adding anhydrous calcium chloride or potassium carbonate to absorb water)

For practical post-collapse purposes, 85-89% ABV is usually the practical ceiling and is adequate for virtually all applications.

Procedure for Multiple Runs

The Stripping Run (First Pass)

The first distillation of fermented wash is called the stripping run. Its purpose is volume reduction and rough concentration, not final product quality.

Procedure:

1. Charge the still with strained, fermented wash.
2. Apply relatively high heat for a fast distillation. Speed is acceptable on the stripping run because you are not trying to make precise fraction cuts.
3. Collect everything that comes over until the distillate proof drops below 20% ABV or the liquid no longer burns when ignited.
4. Discard the foreshots (first 50ml per 20L of wash) but combine heads, hearts, and tails into a single container called the “low wines.”

The low wines from a stripping run of 10% ABV wash typically come out at 25-35% ABV. You have reduced 20 liters of wash to perhaps 5-6 liters of low wines.

Multiple Stripping Runs

If you have a small still and a large quantity of wash, do multiple stripping runs and combine all the low wines. Then do a single, careful spirit run on the combined low wines. This is far more efficient than doing careful runs on each batch of wash.

The Spirit Run (Second Pass)

The spirit run is where quality happens. You distill the low wines slowly and carefully, making precise cuts between heads, hearts, and tails.

Procedure:

1. Charge the still with low wines (25-35% ABV). You may add water to bring the charge to about 30% ABV if necessary. Running very high-proof liquid through a pot still can be dangerous due to rapid vaporization.
2. Apply moderate heat for a slow, controlled distillation.
3. Make careful foreshot, heads, hearts, and tails cuts (see Heads, Hearts, Tails article for detailed guidance).
4. Collect hearts at a rate of 1-2 drops per second for maximum separation.
5. Hearts from a spirit run typically come off at 60-75% ABV.

Third and Subsequent Runs

Each additional run further concentrates the alcohol and removes residual impurities. The procedure is the same as the spirit run: charge the still with the hearts from the previous run, distill slowly, and make careful cuts.

Expected concentrations by run:

Run	Input ABV	Hearts Output ABV
1st (stripping)	8-12% wash	25-35% low wines
2nd (spirit)	25-35%	60-75%
3rd	60-75%	78-85%
4th	78-85%	84-89%
5th	84-89%	~89% (azeotrope limit)

Diminishing returns set in rapidly after the third run. Most applications are well served by double or triple distillation.

Managing Recycled Fractions

One of the key efficiencies of multiple-run distilling is recycling heads and tails.

The Feints System

Professional distillers use a systematic approach to recycling:

1. First run: Collect everything into low wines.
2. Second run: Separate into foreshots (discard), heads (save), hearts (keep), tails (save).
3. Third run: Add saved heads and tails from the second run to the hearts charge of a new second run. The recycled fractions get another chance at separation.

Over time, this recycling system reaches a steady state where the heads and tails containers maintain a roughly constant volume, with ethanol being continuously recovered into hearts while impurities are concentrated and eventually discarded or diverted to non-drinking uses.

Batch Accumulation

If you are doing many batches, accumulate heads and tails from multiple spirit runs until you have enough to fill a still charge (the “feints charge”). Distill this accumulated collection as its own run. The resulting hearts are often surprisingly clean because the impurities have been through multiple separations.

Practical Considerations

Fuel Costs

Each distillation run costs fuel. For a wood-fired still:

• Stripping run: 15-25 kg of firewood per 20L charge
• Spirit run: 10-15 kg per 5L charge (smaller volume, same heat-up time)

A double distillation uses 25-40 kg of wood total. A triple distillation adds another 10-15 kg. Consider whether the higher purity justifies the fuel expenditure for your specific application.

Fuel optimization:

• Insulate the still pot to reduce heat loss. Clay, stone, or earth packing around the pot can reduce fuel use by 30-40%.
• Use retained heat. After removing the still from the fire, the residual heat continues driving distillation for some time.
• Batch efficiently. Accumulate wash and do larger, less frequent runs rather than small daily runs.

Time Investment

Each run takes 3-6 hours including setup, heating, distillation, and cleanup. Double distillation requires two sessions (possibly on separate days). Consider this when planning production schedules.

Safety at Higher Proofs

Higher-proof spirits are more flammable and more dangerous:

• Spirits above 50% ABV ignite readily and burn with nearly invisible flames.
• Vapors from high-proof spirits accumulate in enclosed spaces and can ignite explosively.
• Spills of high-proof spirits create immediate fire hazards.
• Always have water available for fire suppression when working with spirits above 60% ABV.

Still Explosion Risk

Never charge a still with liquid above 40% ABV without first diluting with water. High-proof charges vaporize rapidly when heated, can overwhelm the condenser capacity, and create dangerous vapor pressure. Dilute to 30-35% ABV maximum before distilling.

Judging When to Stop

How many runs do you actually need?

Application	Runs Required	Target ABV
Rough drinking spirit	1 (careful) or 2	40-55%
Quality sipping spirit	2	55-65% (dilute to 40-50%)
Premium spirit	3	70-80% (dilute to 40-45%)
Antiseptic alcohol	2-3	60-70% (dilute to 70%)
Tincture solvent	2	50-80% (varies by plant)
Lamp fuel	2	75-85%
Engine fuel	3-4	85-90%
Maximum purity	4-5	89% (azeotrope limit)

For most communities, a standard practice of double distillation (one stripping run + one spirit run) serves the majority of needs. Keep the third and fourth runs for occasions when you specifically need very high-proof alcohol for fuel or industrial use.

Record Keeping for Multiple Runs

Track each run meticulously:

• Run number (1st/stripping, 2nd/spirit, 3rd, etc.)
• Volume and estimated ABV of the charge
• Foreshots volume discarded
• Heads volume (saved or discarded)
• Hearts volume and estimated ABV
• Tails volume (saved or discarded)
• Fuel used
• Time elapsed
• Any notes on taste, smell, or problems

This data allows you to calculate your overall yield (total alcohol captured as a percentage of alcohol available in the original wash), optimize your cut points, and plan production schedules.

A well-run double distillation captures 80-90% of the ethanol present in the original wash. A poorly run one may capture only 50-60%. The difference is almost entirely in technique, not equipment, which is why careful record keeping and continuous improvement matter more than expensive stills.