Throughout the recorded history of alchemy and distillation, many interesting still designs have been suggested by the renowned philosophers, doctors, and chemists of their time. These scientists sought to improve their stills used for essential oils, mineral acids, and alcohol, and they leave us many creative designs that bear little resemblance to modern stills.
The earliest alembic stills are dated to around 1850 BCE from Cyprus. The ancient stills found there have undergone archeological reconstruction and proven to work well for creating perfumes. Unusual still designs appear centuries later in 4 CE, where Zosimos of Panopolis provides an account of Mary the Jewess and her interesting dibikos and tribikos stills dating to 1 CE. It is the period of roughly the 16th through 18th centuries in Europe that give us a nice variety of unusual and curious still and condenser design sketches. Giambattista della Porto provided designs inspired by mythology and animals. Condensers shaped as cones, zigzags, and right-angled keys appear in the scientific literature in France and Germany at this time. Alchemical recipes for ardent spirits and waters of life are compiled by the likes of John French in London. It is from this period that we have focused our research and recreations from manuscript drawings. It would seem that, over time, these ancient designs have been dismissed as strange, complex, or imaginary. Revisiting these unusual stills and condensers using modern borosilicate glass, temperature monitoring, and analytical tools allows us to observe their performance for consumable alcohol distillation.
We have selected five air-cooled designs from the following scientists for our reconstruction study for craft alcohol distilling:
- Hieronymus Brunschwyg (c. 1500) —
“Twins” circumambulatory still
- Adam Lonicer (c. 1555)
Sharp angle apparatus
- Nicholas Le Fevre (1662)
Apparatus with “zigzag” condenser
- Herman Boerhaave (1693)
Tall conical apparatus
- Johann Conrad Barkhausen (c. 1700)
Twisted helix apparatus
All of the apparatuses were reconstructed using borosilicate glass from sketches of their respective authors. As little to no dimension are provided in the ancient texts, the reconstruction followed the geometry and scaling as closely as possible. All of the reconstructed units are fully functional stills in the United States, therefore, they were assigned serial numbers and reported as an equipment amendment to the TTB in November 2020 under Mohawk Spirits Distillery.
Nicasius le Febure, also known as Nicolas le Fèvre, was born in the Ardenns in the early 17th century. He was a Calvinist and held appointments as a scientist in the French court and later in the English court as the laboratory manager at St. James, London. In his treatise, Traite de Chimie (1646, 1660), he sought to improve the design of distillation apparatuses. It is in this work where we find his curious zigzag condenser. Another French chemist, medical doctor, and fellow Calvinist, Moyse Charas, also gives a similar zigzag air cooled design in his Pharmacopeè Royale Galenique et Chymique (1676–1753).
In operation, the wash in the boiler is slowly brought to a gentle boil. The room temperature was held at 20 °C with air conditioning. As hot vapors enter the zigzag, each section reaches thermal equilibrium, traveling upwards within about ten minutes. The point where condensation occurs is readily visible as the front moves up the apparatus. Hot vapors are moving upwards through a thin film “pipe” of condensate that is returning to the boiler. The 90° angle at each zigzag provides additional contact surface for intimate mixing of the vapor phase and liquid phase as well. The apparatus operates in simple full reflux until the countercurrent hot vapors and condensate climb through all zigzags against gravity and reach the ambix at the top of the zigzag.
This is the largest reconstruction we have undertaken, and is our favorite apparatus out of all of the whole collection, just based on appearance! The zigzags provide the rectification, and we have achieved greater than 92% purity (184 pf) on the first pass with this unit.
The Boerhaave Cone Apparatus
Dr. Herman Boerhaave was born at Voorhout (Netherlands) in 1668 and earned his doctorate at Leyden in 1690, teaching theoretical medicine, then practical medicine, then chemistry. He is one of the scientists who is credited with assigning the word “alcohol” for the spirits of wine. While an esteemed teacher, his contributions to distillation design are limited. There is one mention, however, that is of interest for craft distilling: a “conical condenser in the form of a sugar-loaf”. There is one non-working example of this cone-shaped still built out of copper on display in the Poli Grappa Museum in Bassano del Grappa, Italy.
In operation, the wash in the boiler is slowly brought to a gentle boil. As hot vapors enter the cone, the cone body reaches thermal equilibrium within an hour. Throughout the run, the cone temperature is held steadily at 75 °C from base to apex. Majority of the rising hot vapors condense on the cooler cone walls and are returned slowly as a thin film to the boiler. The thin film edge and condensate “tears” are easily observed in front of bright lighting or cast shadows. The cone is operating in simple full reflux until the hot vapors reach the peak of the cone. A small amount of hot vapors will eventually travel past the peak and into the condensing sidearm, providing the distillate. In careful operation, most of the sidearm is at room temperature, and the distillate is returned at close to room temperature to the receiver flask.
Amazingly, this simple cone will rectify the wash to almost 93% (186 pf) on the first pass! This still operates dropwise and is quite slow to finish a run with the best results. Overheating the wash can overheat the cone, and hot vapors escape the sidearm, turning this into a poor-performing pot still. Patience is a virtue when operating ancient stills!
Hieronymus Brunschwyg (1450–1513) was a “native of Strassburg” and studied medicine at Bologna, Padua, and Paris. He published two very important works on distillation: “The Small Book of Distillation” (1500), and the so-called “Big Book of Distillation” (1512), containing 79 illustrations of distillation apparatuses. It is in the Big Book that we find a curious sketch of the “Twins” or circumambulatory still. This apparatus is interesting because other scientists of the period copied it in their works.
Despite the puzzling arrangement, the operation is straightforward: There is “hot” twin, and a “cold” twin. The hot twin holds the wash, and the cold twin is the receiver. The hot vapors leaving the hot twin have two condensation paths to take: The ambix above it, and the solen tube leaving it. Most of the distillate is observed flowing in downward in the solen into the cold twin. The bulbs above each pot allow rising vapors to quickly expand through a neck into a cooler space. The vapors condense on the ambix walls, forming “tears,” which flow downward by gravity to the solen. The cold twin vapor temperature remains close to room temperature even when the boiler is operating at 90 °C. The hot twin vapor temperature is approximately half of the boiler temperature when distilling.
First pass distillation provides a maximum of about 85% (170 pf) alcohol, provided the boiling is well-controlled and gentle. Overheating a bulb ruins the entire run. This still operates better than a standard pot still, but does not provide as much rectification as the other apparatuses we built.
The Barchusen Apparatus
Johann Conrad Barkhausen (Barchusen in Dutch) was a chemistry teacher in Utrecht around the year 1694. Glassblowing and glass materials by this time were advanced, but the distillation designs were not particularly unique amongst the chemists of this period. The twisted helix condenser used by Barchusen immediate jumps out to the reader because of its unusual shape: It is simply one single long air-cooled glass tube formed into this shape.
In operation, the wash in the boiler is slowly brought to a gentle boil. The room temperature was held at 20 °C with air conditioning. Countercurrent hot vapors are moving upwards into the helix through a thin film “pipe” of condensate that is returning to the boiler. Each bend provides additional contact surface for intimate mixing of the vapor phase and liquid phase. The apparatus operates in simple full reflux until the hot vapors climb through seven bends and reach the peak. After the peak, the vapors and condensate are no longer working against gravity, and they enter the cooler side of the apparatus. There, the vapors are condensed and ride down the other half of the helix to the receiver.
This wildly shaped apparatus provided the highest purity alcohol of all of the ancient stills we reconstructed: Over 93% purity ethanol (186 pf) on the first pass. That feat was accomplished with just a twisted tube, with no running water or coolant, and a very simple heating mantle! Perhaps our distiller-predecessors were on to something here!
Adam Lonicer (1528–1586) was the town physician in Frankfort, Germany. He studied medicine and mathematics and taught at the University of Marburg circa 1553. He authored the works Naturalis historie opus novum (1551), and Herbarium (1555), which contained a special appendix about distillation. A strange apparatus is provided which Lonicer intended for essential oil extraction. There is one nonworking example of this still on display in the Poli Grappa Museum on the left of the entrance if you look carefully!
Our reconstruction of the Lonicer apparatus was limited only to the second key-shaped condenser in the ancient sketches. We interpreted the sketches to show that the first unit is a reflux column and is hot along its entire path. The condenser is the second key-shaped unit positioned on top of a thumper. We decided that, given careful temperature control, only one apparatus was required to understand how this design functioned.
Once boiling begins, hot vapors rise up the first straight section and reach the first 90° bend in the crook. At this point, reflux of the condensate is observable, and the liquid-vapor front moves through the crook quickly to the second 90° bend. The next straight section slows this progression, and all the while, there is visible return of the condensate to the boiler by gravity. The most difficult control point is keeping the hot vapor edge at the peak of the angled top, not allowing it to pass through to the long downward arm. The boiler temperature control is not quick enough to adjust for this. Adding or subtracting a cooling fans and aluminum foil wrap helped to control this.
Amazingly, just a few 90 degree bends is all it takes to create rectification and a number of theoretical plates of separation! We were able to achieve greater than 92% purity (184 pf) on the first pass distillation with this unit.
The careful reconstruction of five ancient distillation apparatus has proven that these forgotten and esoteric designs are capable of producing high purity ethanol on a single distillation run using only air cooling. The curious angles and bends in the Barchusen, LeFèvre, and Lonicer designs act as plates of separation and enrich the vapor phase. The highest purity observed in this research project was 93.11% pure ethanol from the Barchusen apparatus. Interestingly, a simple cone shape will also provide as high as 92.78% pure ethanol, as demonstrated by the Boerhaave apparatus.
These ancient designs are not without challenges. The room temperature must be cool throughout the distillation run, and air conditioning is a requirement during the summer months. Because the purity of alcohol distillate from these stills is always very high throughout the entire run, “cuts” must be made by taste and smell. Wide temperature swings or large changes in proof are not observed until very late in the distillation run. Sizing the boiler and carefully controlling the boiler rate are paramount. It is very easy to overheat these designs and sent hot vapor through the entire apparatus with aggressive boiling.
We believe our research is the first successful reconstruction in glass of such designs in glass in centuries. We encourage craft distillers to reconstruct and scale up these easy designs in copper for the production of boutique craft spirits, and hopefully differentiate their brands with an exciting twist of history from the 16th to 18th centuries!
Mohawk Spirits Distillery would like to thank the American Distilling Institute and President Erik Owens for their grant award that made this research possible. We would like to extend special thanks to our glassblowing partner, Q-Glass (Towaco, New Jersey) for their help with apparatus construction. Finally, we thank our legal partner, Hops & Vine Consultants (www.hopsandvine.net, New York), for their assistance with the TTB equipment registration of all of the stills described in this report.
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