Name: Eric Stroud
Owner and distiller, Mohawk Spirits Distillery
PhD, Organic Chemistry (2013, Seton Hall University); MS Environmental Engineering (1997, NJIT); BS Chemical Engineering (1995, NJIT)
Laboratory distillation and separations experience: 24 years. Craft distilling experience: 4 years
20 years: Pfizer (research scientist, 1995-1998); Syvax Inc. (principal investigator, 1998-2004); SharkDefense Technologies (principal investigator, 2004-2015).
Please provide how your background experience will provide the foundation for your research:
Dr. Eric M. Stroud has dedicated his career to organic chemistry and novel chemical signal research. He led the group of scientists that discovered, isolated, and commercialized the first shark repellent pheromones, has formulated a variety of products for pharmaceutical, medical device, and invasive species control, and hold 11 patents.
Distillation is a core discipline in all of his work, past and present. Dr. Stroud is proficient on a number of distillation techniques, including vacuum fractional distillation, spinning band, and molecular falling film. In 2015, he founded Mohawk Spirits Distillery, Canajoharie, New York (Mohawk Spirits, LLC). Mohawk Spirits Distillery is the first farm distillery in Montgomery County, New York, and farms pawpaws, medlars, and rare fruits. Within 3 years, Mohawk Spirits was won nine medals in international spirits competitions, including two silver medals from ADI (2017, 2018). Mohawk Spirits is set up as a research distillery and laboratory, with a number of small scale separation units and laboratory equipment to study novel distillation techniques.
Dr. Stroud is a graduate of, and is currently a collaborating scientist with Seton Hall University and Dr. James E. Hanson in the Department of Arts and Sciences. Seton Hall University provides state of the art analytical equipment, such as time-of-flight mass spectroscopy (GC-MS(Tof) and nuclear magnetic resonance. The GC-MS(ToF) instrument is useful for quickly characterizing how well a still can separate and purify ethanol, as well as a flavor and fragrance compound identification.
Mohawk Spirits Distillery proposes to fabricate and evaluate three ancient still designs dating back to the 16th century in order to prove or disprove that such designs are practical in modern craft distilling. The ancient stills will be constructed using modern materials and a controlled study will be performed to measure the efficiency of the separation in each unit.
While the cucurbit, Moor’s head, and alembic designs have prevailed into our present time, there are historical distillation unit designs that warrant a new investigation using modern materials such as borosilicate glass, digital temperate controllers, and sensitive instrumental analysis. A modern investigation would provide obvious improvements over the limited materials used in the stills fabricated in 16th-18th centuries, such as temperature stability through the run. A controlled study using current scientific techniques may provide the craft distilling industry with a more efficient distillation process, a unique still design for brand differentiation, or a method to produce a superior-tasting distilled spirit.
Throughout the recorded history of distillation, numerous sketches of unusual and intricate designs appear from European alchemists, scientists, and philosophers. Many of these historical designs exist only in manuscripts. A few non-functioning extant stills are currently found in European museums or the Poli Grappa Museum (Bassano del Grappa, Italy). This proposal shall focus on the designs published by three scientist-philosophers:
1. Hieronymus Brunschwyg (1500) – “Twins” still (Figure 1, attached)
2. Nicholas Le Fevre – (1662) – Apparatus with “zigzag” condenser and moor’s head (Figure 2, attached)
3. Herman Boerhaave (1693) – Tall conical condenser (Figure 3, attached)
While no peer-reviewed publications on the recreation of ancient still designed has been found in our literature search, a proof of concept exists.
Mohawk Spirits Distillery recently researched an ancient design by Giambattisa della Porta (1535-1615) and successfully demonstrated a modern distillation process for grape marcs to produce an excellent brandy. The distillation unit was based on della Porta’s “hydra” and “pelican” sketches. Our research unit was constructed with Kimax glassware, with custom glass blowing performed by ProGlass (China) and Q-Glass II (New Jersey). Digital temperature controllers were applied to the boiler and each stage, a distillation was performed without any liquid coolant or closed-cycle refrigeration. A complete separation of the wash into an excellent consumable brandy product was made using only pressure drop (flash drum) and simple reflux principles. This distillation apparatus was assigned serial numbers and was registered with the TTB in 2019. A picture of this unit is attached to this proposal (Figure 4).
The recreation of the della Porta’s hydra-pelican is a successful proof of concept. Videos and pictures of this unit are available upon request. This research proposal seeks to investigate and validate other distillation unit designs from della Porta’s period.
Each unit will be constructed with borosilicate glass. Boiler capacity will be at a scale between 1 liter to 22 liters, depending on the complexity of the joints and access points. This size will produce enough consumable alcohol for an independent taste evaluation by a separate panel. The clear glass will allow the researcher to observe how the vapor-liquid equilibrium behaves during the distillation run.
Simple glassware modification will be done in-house with a brazing torch. Complex glassblowing will be performed by Q-Glass (Montvale, New Jersey). Each unit will be designed to incorporate at least one temperature sensor at the boiler and one temperature sensor in a condenser. Chemical analysis of the washes and distillates will be performed at Seton Hall University (South Orange, NJ) using a Leco Gas Chromatograph and Time-of-Flight Mass Spectrometer.
A standard test “wash” will be distilled in each unit. The test wash will be a standardized solution of purified water, pure ethanol (representing the “hearts”), pure acetone or acetaldehyde (representing the “foreshots”), pure methanol (representing the “heads”), and pure n-butanol (representing the “tails”). The efficiency of the separation and percent yield will be compared across all three units and a fourth modern pot still. For each fraction, odor, ease of operation, and duration of the distillation run will also be recorded. These fractions will be not consumed. A GC-MS(ToF) analysis using peak height area will be performed on the distillate fractions collected to further study the separation efficiency of the modern pot still versus the three historical designs.
Once the operation of each unit is well understood, a second series of comparisons will be performing using a food-grade (consumable) wash. If required, a pure copper metal sponge will be inserted in each still to bind organosulfides. The same wash will be used in all four units. The consumable spirits fraction from each unit will be sent to other evaluators for an organoleptic study and blinded judging.
Within one year of the award, the following milestones will be achieved:
1. MONTHS 1-3: Fabrication of the of the Brunschwyg, LeFevre, and Boerhaave apparatus
2. MONTH 4: Distilling the standard wash solution through each fabricated unit and a modern still
3. MONTH 5: Analyzing the distillates from all four units using GC-MS(ToF)
4. MONTH 6: Distilling a consumable wash through all four units for an independent tasting panel
5. MONTHS 7-8: Submission of all required reports to the TTB for registration of the stills and alcohol produced
6. MONTHS 9-10: A summary report to ADI on all results, along with the analytical data from the GC-MS(ToF)
7. MONTHS 11-12: Videos of each device in operation, suitable for the Internet or social media
$4,500.00 – Total funds requested.
$3,000.00 – MATERIALS: Custom glassblowing costs, to be provided by Q-Glass II (Towaco, New Jersey), estimated at $1000.00 / still, inclusive of raw materials, glassblowing time, adjustments, and shipping.
$1,000.00 – ANALYSIS: Instrumental analysis, inclusive of gas, columns, and consumables. Estimated at $100/sample, 5 samples for standard solution analysis, 5 samples for consumable sample analysis
$500.00 – SERVICES: Video production and editing costs of the stills in operation, suitable for ADI use, conferences, and presentations
Mohawk Spirits Distillery will provide, gratis, professional time, mash material, yeasts, chemicals, containers, and distillery consumables. Mohawk Spirits Distillery will also ensure that all stills constructed are registered with the Alcohol and Tobacco Tax and Trade Bureau, and that all required monthly reports are submitted.
The final stills will be shipped for display and demonstration at any ADI conference or workflow, as requested.
This research proposal will benefit the craft spirits industry by providing feasibility data on ancient still designs. If these designs prove practical, a craft distiller will be able to differentiate their products by marketing about the use of a historical design, e.g. produced using a “ancient design” or “16th century method”. These designs may prove to provide a better organoleptic profile than modern stills for certain types of spirits, hypothetically, fruit brandies. Potentially, these designs may have less energy input requirements than modern stills, or cheaper manufacturing costs.
A primary reference for the historical designs considered in this research proposal are found in “Short History of the Art of Distillation”, Forbes, R. J. E. J Brill, Leiden, Holland. 1948. pp. 79-80, 207-210. Sketches of these units are attached to this proposal.
Boerhaave, H., “Elementa chemiae” (Leiden, 1731/1732, 2 vols.).
Boerhaave, H., “Elements de chimie” (paris, 1754, 6 vols.).
Brunschwygk, Hier, “Liber de arte distillandi de simplicibus oder Buch der rechten Kunst zu Distillieren die eintzigen dinge” (Strassburg, 1500, Johann Gruninger, the so-called “Small Book of Distillation).
Brunschwygk, Hier, “Liber de arte Distillandi de Compositis; Das Buch der waren Kunst zu distillieren die Composita and simplicia und das Buch thesaurus pauper” (Strassburg 23 Februar 1512, the so-called “Big Book of Distillation). (Other editions: Strassburg 1519, 1531; Francfort 1553, 1594, 1598, and several adaptions by Ulstad, Ryff, Uffenbach).
Lemery, N., “Cours de cymie contenant la maniere de faire les operations en usage dans la medicine par une method facile avec des instructions et raisonnements sur chaque operation our l’instruction de ceux qui veulent s’appliquer a cette science” (Paris, 1675, 1744, and 21 more editions).
Mohawk Spirits Distillery, online (February 6, 2020): http://www.mohawkspirits.com