Climate change spares no industry, and the production of eaux-de-vie, particularly their barrel aging, is no exception. The influence of climatic variations on the organoleptic properties and stability of the final products has become a major concern for quality-conscious producers.
To understand the impacts of climate change, it is essential to revisit the origins of the compounds that define the very essence of eaux-de-vie.
After exploring the origin of volatile aromatic compounds in fermented raw materials (Consequences of Climate Change on the Quality and Stability of Spirits – Part 1), this second part focuses on the role and importance of controlling continuous or batch distillation to achieve the desired eau-de-vie quality.
The final part of this series will address the key physicochemical changes that eaux-de-vie undergo during barrel aging.
This three-part journey will provide insights into the effects of climate change on the composition of barrel-aged eaux-de-vie and propose potential solutions to preserve their quality.
Modification of volatile compound composition
during continuous and batch distillation –
Quality criteria
Role of distillation in composition of eaux-de-vie
Distilation serves several purposes:
- Producing new volatile aromas
- Concentrating volatile compounds already present in the raw material
- Sorting to limit the presence of undesirable compounds
- Eliminating certain unwanted compounds
1- Volatile compounds likely to form during distillation
During the heating phase, new aromatic compounds will form depending on various factors: medium acidity, presence of lees, heating duration, heating temperature and type (gas, wood, electricity), type of equipment, copper thickness, distillation method, etc.
This section presents the main families of compounds that form during distillation, along with their key representatives, which influence the organoleptic properties of eaux-de-vie.
1a- Release of fatty acids and fatty acid esters from yeasts
Before distillation, these compounds are retained in the cell walls of yeasts. They are mainly released when fermentation lees are incorporated into the raw material for distillation. This process enriches the distillate with aromas and texture. It is similar to less stirring (“bâtonnage”) in white wines, which enhances aromas and adds roundness to the wine.
The key representatives with a strong fruity and floral aromatic interest are fatty acid esters:
Ethyl caproate, ethyl caprate, ethyl caprylate, isoamyl caprylate and isoamyl caprate.
However, heavier esters can lead to undesirable odors. This is the case for: Ethyl myristate, ethyl palmitate, ethyl linoleate, and ethyl linolenate. The corresponding fatty acids can also cause cold instability issues.
The aromatic impact of these compounds in eaux-de-vie is detailed in Annex 2 at the end of this article.
1b- Varietal aromas from precursors in the raw material
Some non-volatile aroma precursors may remain trapped in the fermented raw material, often because they are bound to sugars.
Through heat and acidity, hydrolysis reactions occur, releasing volatile aromas. Among the most well-known compounds from grapes or fermented fruits:
- Terpenes, such as Linalool (floral notes of lavender, lily of the valley) and Geraniol (rose and geranium notes).
- Or also, Ketones, such as beta-ionone (violet aroma).
1c- Compounds formed from key chemical reactions in the “boiler”
The boiler acts as a true chemical reactor, where various reactions occur, often facilitated by the presence of copper. Some key reactions include:
- Esterification: Alcohol + Acid → Ester + Water (e.g., ethyl acetate, isoamyl acetate)
- Acetalization: Alcohol + Aldehyde → Acetal + Water
- Maillard Reactions: Sugars + Amino Acids → Formation of furans, pyrazines, etc.
- Strecker Reactions: Involving amino acids, leading to the formation of aldehydes such as acetaldehyde (ethanal).
⇒ Among the many compounds formed during these reactions that influence organoleptic properties, two of the most common across all raw materials for distillation are acetal and furfural.
– Acetal
Origin: Acetal is primarily formed from the reaction of ethanal (acetaldehyde) with ethanol. The presence of ethanal favors acetal formation.
- Sulfiting the raw material or fermentation to prevent spoilage contributes to ethanal formation.
- In the presence of residual sugars (glucose, fructose), heating causes thermal degradation, producing light aldehydes such as ethanal.
- Ethanal can also be formed through Maillard or Strecker reactions.
Aromatic Impact: Acetal contributes to dried fruit notes. However, at high concentrations (> 50 mg/L), it can mask subtle aromas and even be perceived as burnt alcohol.
Note: In the presence of ethanal, acetal will continue to form during distillation and aging, reacting with ethanol over time.
– Furfural
Origin: The primary source of furfural during heating is the thermal degradation of pentoses (non-fermentable sugars).
Fermented raw materials rich in pentoses typically come from plant materials high in hemicellulose, which is less common in most spirits, as they are generally derived from hexose-rich sources (starch, sucrose).
Furfural can also form in small amounts via Maillard reactions in the presence of residual sugars (glucose, fructose, pentoses).
Aromatic Impact: Low levels of furfural produced during heating are not detrimental to eau-de-vie. On the contrary, they contribute positively to its aromatic bouquet.
⇒ Among the main esters generated by the reaction between various alcohols and acids in the medium, we can highlight fruity aromas that can be routinely analyzed:
2- Concentration of volatile compounds during distillation
Distillation enables selective evaporation: The principle of this evaporation depends on the type of distillation used. This topic is further explored in the following section: “Different distillation principles and their impact on volatile compounds”.
By removing as much water as possible, distillation increases alcohol and aroma concentrations. However, it also has the potential to amplify flaws present in the raw material, making it essential to implement a selection process during distillation.
3- Selection process of volatile compounds during distillation
Whether it involves removing “heads” or “tails,” making cuts at specific distillation plates, or utilizing reflux mechanisms in distillation columns, the selection process aims to minimize raw material defects while optimizing the concentration of desirable aromatic compounds.
For the selection process to be effective, it is crucial to consider both the type of distillation and a deep understanding of how key volatile compounds behave during distillation. This topic is further explored in the following section: “Different distillation principles and their impact on volatile compounds”.
4- Capture of undesirable compounds by copper
– Sulfur compounds
Sulfur compounds (methanethiol, ethanethiol, and dimethyl trisulfide) have extremely strong odors even at very low concentrations. These compounds can be captured by the copper surfaces of distillation equipment, where they precipitate as sulfides and can subsequently be filtered out.
– Fatty acids
Heavier fatty acids can become insoluble when the alcohol content drops too low, leading to instability in the final product or even rancidity. By reacting with copper, these fatty acids form complexes that precipitate, allowing them to be removed through filtration.
Maintaining the copper surfaces of the distillation apparatus is essential to ensure their optimal efficiency in removing these undesirable compounds.
Different distillation principles and their Impact on the volatile composition of Eaux-de-Vie
The distillation of spirits, such as wine eaux-de-vie, fruit eaux-de-vie, rum, whisky and tequila, can be carried out using various methods, depending on tradition, regulations, and the producer’s objectives: Batch distillation (single-pass or double distillation) or Continuous column distillation.
Although different types of distillation have varying effects on concentration, separation, and the removal of undesirable compounds, they share the following fundamental principles:
1- Shared characteristics of the various distillation methods
– Ethanol is more volatile than water
Ethanol evaporates more easily than water, allowing its gradual enrichment in vapor during distillation. however, there is a specific interaction between water and ethanol, known as the azeotropic phenomenon.
– Ethanol and water associate: azeotropic phenomenon
Water and ethanol form an azeotropic mixture, meaning their combined boiling point (78.15°c) is slightly lower than that of pure ethanol (78.43°c). This phenomenon limits the maximum ethanol concentration that can be achieved by simple distillation to 96.5% vol. (under normal atmospheric pressure). Beyond this concentration, ethanol and water vapors have the same composition, making further separation impossible without special techniques used to produce neutral alcohol.
– Ethanol concentration changes throughout the distillation process
At the beginning of distillation, the first vapors are rich in ethanol. as the temperature rises in the boiler, ethanol gradually decreases in the vapor phase, as less volatile compounds (such as water) become more dominant. this evolution depends on the type of distillation (continuous or batch) and how the distillation process is conducted.
– The transfer rate in the vapor phase varies for different volatile compounds
The vapors formed during distillation do not contain only water and ethanol but also other volatile compounds. these compounds are carried along depending on:
- their boiling point: compounds with a boiling point lower or close to that of ethanol, such as ethanal (acetaldehyde), concentrate in the first fractions.
- their affinity with ethanol: some compounds, such as ethyl acetate and acetic acid, although not highly volatile, can be carried by ethanol vapors due to molecular interactions.
Methanol is an Exception: Methanol is a highly volatile compound (boiling point: 64.7°C) that is carried along with ethanol throughout the entire distillation process. This occurs due to its similar volatility to ethanol and its chemical affinity with ethanol. Additionally, methanol is trapped in the pectins of certain raw materials and can be gradually released during distillation.
Due to its toxicity, international regulations set maximum limits for methanol in spirits. For example, 200 g/hl AP for wine eaux-de-vie produced in the European Union [1].
It is difficult to reduce methanol solely through distillation, as this requires specialized equipment.
Instead, it is preferable to control methanol levels in the raw material before fermentation.
For more details, refer to the blog article: “Consequences of Climate Change on the Quality and Stability of Spirits – Part 1“.
2- Batch distillation with Double distillation – Quality of eaux-de-vie
2.1 Principle
It consists of performing a first distillation with the collection of a certain volume of Heads, Hearts, and Tails. It is called “Second distillation” because the Hearts from the first distillation is redistilled, possibly with fractions of Heads and Tails.
Interest in redistilling the Heart:
The maximum alcohol content that can be achieved in the Heart of the first distillation is limited. To obtain a higher alcohol concentration, “Second distillation” is necessary. Moreover, recycling Heads and Tails into the Hearts of the distillation enhances the complexity of the product to be distilled. This blend is called “Low wine” and typically has an alcohol content of 25 to 35 % vol..
During both distillations, the alcohol concentration in the vapors is at its highest at the beginning and then gradually decreases to just a few percent. As the liquid in the boiler is depleted of alcohol, water becomes the dominant component.
2.2 Effect on Concentration
This distillation method generally allows the alcohol to be concentrated up to a factor of 10, with the maximum alcohol content in the Eau-de-Vie typically between 70 and 85 % vol..
2.3 Effect of Selection
The collection of Heads and Tails during the first and second heating phases helps to limit certain defects in the fermented raw material.
Some of these fractions can be recycled, either into the product to be distilled in the next first heating or into the Low wine.
Through these different collections and their possible recycling in distillation, Le Tri can be highly effective in finely correcting organoleptic defects caused by volatile compounds in excessive concentrations.
2.4 Main parameters of batch distillation affecting the composition of Eaux-de-Vie
- Shape and material of the still
- Temperature and quality of the cooling water
- Heating temperature and flow rate
- Volume of Heads and Tails collected
The Shape of the Still
The shape of the still plays a crucial role in the selection process during distillation:
- Height and inclination of the swan neck influence vapor purification.
A tall neck promotes better separation and reflux, especially with a high inclination. - Width and shape of the boiler affect the smoothness of evaporation.
At equal capacity, a wider boiler provides a larger evaporation surface, leading to gentler and more homogeneous evaporation. - Presence of a cap (shape of the shoulder).
An onion- or dome-shaped cap induces partial condensation of heavy compounds, encouraging natural reflux and better purification of vapors.
A more straight or angular shape allows vapors to pass more directly, increasing the presence of heavy compounds in the distillate.
Conclusion on the effects of the still shape
The natural reflux induced by the overall shape determines the purity or richness of the distillate. A shape that promotes significant reflux leads to a more purified distillate, while reduced reflux results in a richer and more complex distillate.
The choice of still shape depends on the type of spirit desired, ranging from a light and refined distillate to a complex and aroma-rich distillate.
Every design detail contributes to the unique characteristics of the final product.
Material and thickness of the still
The type of material and its thickness influence:
Heat exchange
A thin wall allows for rapid heating, while a thicker wall distributes heat more slowly and evenly.
Slower heat diffusion enables more controlled temperature rise, which can influence the efficiency of the selection process.
Chemical reaction
Copper captures certain undesirable compounds, such as sulfur compounds.
It acts as a catalyst for specific reactions, such as those between alcohols and acids that produce aromatic esters (e.g., isoamyl acetate, which has a banana aroma).
Heating Temperature
It has a significant impact on the evaporation or retention of certain compounds at the alcoholmeter ports:
- If set too high, it will evaporate the most aggressive volatile compounds but allow too many heavy fatty acids to pass through, which can lead to heaviness in the distillate.
- If set too low, it may result in reduced aromatic complexity.
Controlling this temperature at different distillation phases is part of the distiller’s expertise.
The ability to regulate this temperature depends on controlling cooling water temperatures, which requires proper equipment for water production and temperature control.
Flow Rate
The flow rate influences the arrival of the “secondes” (the fraction between the Hearts and the tails, which contains most of the esters and aromatic fatty acids).
- A slower flow rate delays the arrival of the secondes, which are rich in fatty compounds.
- A faster flow rate brings the secondes in more quickly.
This explains why, to achieve optimal results when distilling with lees, the distillation speed should be relatively slow. A slower process helps to:
- Effectively separate the Heads from the secondes.
- Enhance the recovery of fatty acid esters, which contribute to the expected structure and aromatic balance.
Expert Marc GIBOULOT highlights the following point: “In double distillation using a pot still, a slow distillation speed and a high eau-de-vie cut (between 61-63 % vol) help limit the arrival of the secondes, which is more challenging in Armagnac-style column distillation.”
Water Quality
Using overly hard water can lead to scale buildup in the water circuits, progressively reducing cooling efficiency.
2.5 Volume of Heads and Tails collected – Recycling of these fractions
The quantities of Heads and Tails to be collected depend on a thorough understanding of the distillation equipment and the volatile compound profile of the fermented raw material.
Some experienced distillers are able to adjust the cut points in real time through tasting and olfactory evaluation, determining the appropriate fraction for the distillate as it flows.
In the absence of this expertise or the support of a specialist to fine-tune the equipment and define the distillation process, it becomes essential to:
- Analyze the key volatile compounds in the raw material.
- Study the passage rates of these compounds in relation to the equipment settings.
This approach ensures optimal separation and improves the overall quality of the distillate.
2.6 Examples of the behavior of certain compound families during distillation and the impact of selection
Aldehydes: Ethanal – Acetal
These compounds are primarily found in the Heads of the distillation. If present in excess in the raw material, they can be reduced by carefully adjusting the Heads cut.
Light Esters (Ethyl Acetate) – Fatty Acid Esters and Fatty Acids
Due to their affinity with ethanol, most light esters and fatty acids have a decreasing passage rate as distillation progresses.
Excessive removal of Heads can result in a significant loss of aromatic potential from these compounds.
Conversely, fatty acids tend to increase in concentration as distillation continues. Therefore, excessive removal of Tails may deprive the eau-de-vie of their contribution to roundness and texture.
Ethyl Lactate – Ethyl Succinate
Their passage rate increases during distillation, making them useful markers of Tails content in eaux-de-vie.
Higher Alcohols
Most higher alcohols are primarily found in the Hearts of the distillation. Once present in excess, they become difficult to remove, potentially lowering the final quality of the product by making the eau-de-vie heavier or even vegetal.
2.7 Selection has its limits
Based on the points discussed, if the selection process is not adapted to the composition of the raw material, it can lead to:
- Loss of essential aromatic compounds, such as fatty acid esters.
- Retention of undesirable compounds, which may negatively impact the quality of the eau-de-vie.
Examples of passage rates for key volatile compounds in a Cognac-style distillation are provided for reference in Annex 1 of this article.
2.8 Conclusion on batch distillation with “Second distillation” and the Quality of Eaux-de-Vie
When starting with high-quality raw material, mastering the operating settings of the distillation apparatus and performing a precise selection process based on the raw material’s composition can result in the production of highly refined eaux-de-vie.
To learn more about pot still distillation
Refer to the bibliographic references cited at the end of the article.
3-Batch distillation without “Second distillation”
3.1 Principe
This method consists of performing a single distillation, with the collection of a certain volume of heads, hearts, and tails.
3.2 Main differences from batch distillation with “Second distillation”
– These stills are primarily used for the production of fruit eaux-de-vie, marc spirits, or plant macerations.
– Their use is often preferred for artisanal production due to their lower efficiency, making them less suitable for industrial-scale production.
– To obtain complex eaux-de-vie without second distillation at a high alcohol content, a specific still design is required (Examples: Stupfler® still, pot still with an integrated column, and Muller still). These types of equipment allow for a simplified single-pass distillation while ensuring precise fractionation of compounds.
– Heating is generally performed using a bain-marie system, sometimes with direct or indirect steam, and rarely with gas. These heating methods provide even heat distribution, which helps prevent “rimé” (burns or overheating), especially in raw materials rich in dry extracts, such as marc or fruit fermentations from plums, pears, or cherries.
– These stills are often easier to operate, as maintaining a temperature close to 100°C at the base of the column ensures a complete passage of alcohol. However, some are equipped with a hydraulic dephlegmator, which enhances volatile compound separation by adjusting reflux. This feature helps retain heavier compounds in the lower sections of the still while increasing the alcohol concentration in the distillate.
– As with batch distillation with second distillation, the effectiveness of the separation between Heads, Hearts, and Tails largely depends on the design of the still. Key factors include:
3.3 Conclusion on batch distillation without “Second distillation” and the Quality of Eaux-de-Vie
With high-quality raw material, precise control of the distillation equipment settings, and a well-executed separation process based on the composition of the raw material, this method is capable of producing highly refined eaux-de-vie.
The initial investment may be more expensive, but with a higher yield and lower energy costs compared to batch distillation with “Second distillation”, the choice of this method depends primarily on the type of spirit to be produced and the production objectives.
4- Continuous Column Distillation
4.1 Principle
Continuous distillation is based on an uninterrupted flow of raw material through a distillation column, allowing for the constant separation of different constituents. The mixture to be distilled is continuously introduced into the column, where it passes through successive rectification plates.
- Alcohol and volatile compounds rise as vapor toward the top of the column.
- Heavier residues (such as water) descend and are removed at the bottom of the column.
- At each level of the column, partial condensation of the vapors allows interaction with the liquid phase, promoting progressive alcohol concentration as the vapor rises.
4.2 Effect on Concentration
Continuous distillation allows for higher alcohol concentrations than batch distillation, thanks to continuous rectification on each plate. Depending on column design and the number of plates, alcohol can be concentrated up to 96%, making it ideal for neutral alcohol production.
4.3 Effect of Selection
In continuous distillation, the optimization of volatile compound separation relies on precise and stable settings of the column. These settings include:
- Number of plates
- Temperatures
- Liquid and vapor flow rates
- Reflux conditions
Unlike batch distillation, where manual cuts allow for direct selection of fractions, continuous distillation relies on an automated and continuous separation of compounds at different levels of the column:
- The separation of Heads, Hearts, and Tails happens continuously, with each compound extracted at a specific level of the column based on its boiling point.
- Precise temperature and pressure control allows for the adjustment of compound concentrations, depending on the desired characteristics of the eau-de-vie.
Example: The more plates a column has, the greater the temperature difference between the first and last plate, and the more effective the reflux becomes, refining the separation of volatile compounds.
4.4 Conclusion on continuous distillation
Continuous distillation offers many financial advantages over batch distillation:
- Lower investment costs
- High yield, with continuous production
- Reduced labor costs
- Less raw material loss
- Energy savings
However, continuous distillation has limitations when it comes to recovering heavy and structuring compounds, such as fatty acids and their esters, which are essential to aromatic complexity. Due to their low volatility, these compounds tend to concentrate in the lower plates or remain trapped in the column residues.
Example: During an attempt to recover certain fatty acid esters known for their positive aromatic properties, I observed that an undesirable compound, allyl alcohol, with its harsh characteristics, was extracted at the same level. In this type of column, preserving beneficial aromatic compounds requires rigorous bacterial management from the fermentation stage to limit the production of unwanted compounds, such as allyl alcohol (for more details on the origin of this compound, refer to the blog article on volatile compounds from fermentation: “Consequences of Climate Change on the Quality and Stability of Spirits – Part 1“).
For further reading on continuous distillation: refer to the bibliographic references at the end of the article.
C onclusions on the impact of still selection on the composition of Eaux-de-Vie
Hundreds of volatile compounds can be found in eaux-de-vie. It is the harmonious balance of these compounds that gives the final product its desired quality.
Regardless of the distillation method, it cannot completely correct major defects in the raw material without compromising the composition of the eau-de-vie.
Therefore, optimizing distillation begins with optimizing the quality of the fermented raw material and maintaining strict quality control throughout the process.
Ranges of volatile compound concentrations to be respected
Beyond regulations linked to appellations, which specify minimum or maximum limits, it is difficult to establish precise guidelines for volatile compound concentration ranges without knowing the intended purpose of the eau-de-vie whether it will be used to produce “Blanche” or aged in barrels, and for how long ?
As a result, the definition of a volatile compound profile can vary significantly depending on the characteristics of the final product intended for commercialization.
Key Steps in Defining an Appropriate Volatile Compound Profile:
- Refer to analytical specifications from appellations, especially those required by European regulations, export country regulations, importers, or specific client requirements.
- Define the desired profiles based on client expectations. This includes:
– Analyzing the profiles of successful products in the market
– Conducting comparative analyses of existing commercialized products that closely match your target profile. - Consider the state of your stocks, including eaux-de-vie currently in finishing or aging, to determine your needs.
- Obtain analytical data on the key volatile compounds in freshly distilled eaux-de-vie, complemented by sensory tasting notes.
- Understand the evolution of organoleptic properties during finishing or barrel aging, to anticipate how the eau-de-vie will develop over time.
By following these steps, you can establish a precise and adaptable volatile compound profile suited to the intended spirit and market demands.
Examples:
- For a “White” eau-de-vie, highly volatile and aggressive Heads compounds (such as acetaldehyde, isobutanal, and acetal), higher alcohols, and heavy compounds (such as fatty acids) should not be present in excess. On the other hand, a small amount of fatty acid esters can add smoothness (e.g., between 20 and 30 mg/L for a finalized product at 40% vol.).
- A freshly distilled eau-de-vie that seems “soapy” due to an excess of fatty acid esters may not be suitable for direct commercialization as “Blanche.” However, during aging, it can develop complex floral and fruity aromas while enhancing smoothness.
Note: For barrel aging, the recommended volatile compound composition depends on several factors:
- Aging duration
- Type of wood (new barrels or previously used barrels)
- Wood grain (fine grain vs. coarse grain)
- Barrel size
- Type of toasting…
Given how these compounds evolve during barrel aging: evaporation of light compounds, concentration effects, wood extraction, chemical reactions, etc…
It is the expertise of the Maître de Chai or Master Blender to define the target profiles for the eaux-de-vie to be produced.
Blending different eaux-de-vie allows him for modulating the aromatic profile as desired. Discover OPTIMIX!
If you do not have established quality criteria or the necessary experience, consider consulting experts such as Ludwig VANNERON, Marc GIBOULOT, Thierry ARCHEREAU, who can assist you in defining these criteria through tasting and analytical assessments.
Specific training programs are offered at CIDS in Segonzac (France).
At the end of this article, two annexes provide information about the relationship between volatile compound profiles and aromas:
ANNEX 2 presents a non-exhaustive summary of the main volatile compounds that can be routinely analyzed and/or easily detected through tasting (such as sulfur compounds). It outlines their organoleptic impact on freshly distilled eaux-de-vie and provides, for reference, the recommended maximum concentrations to ensure an eau-de-vie free of major defects, as well as their behavior during batch distillation with “Second distillation”.
ANNEX 3 presents a non-exhaustive summary of the main organoleptic descriptors of eaux-de-vie and the key volatile compounds that may correlate with these descriptors.
To optimize Eaux-de-Vie blends with the new tool OPTIMIX
Blending eaux-de-vie after distillation is an excellent way to achieve the desired profile, whether for immediate production or for aging in barrels.
By using analytical data, particularly the analysis of key volatile compounds, it is possible to optimize this blending process.
An online application, OPTIMIX, has been designed to help you plan and refine your blending trials with precision and efficiency.
A blog article is dedicated to the benefits of creating blends with Optimix and lists some practical application examples: “Optimix – a tool to optimize your blends“.
Impact of Climate Change on the Composition of Eaux-de-Vie
This article and the previous one have examined the origins of the main volatile compounds responsible for the organoleptic properties of freshly distilled eaux-de-vie. They have also provided key insights into controlling their concentration profile to achieve the desired product quality, drawing on our expertise in the evolution of eaux-de-vie during refining and aging.
However, climate change can significantly impact the physicochemical maturation processes in barrels, potentially requiring adjustments to the profile of these eaux-de-vie.
As mentioned in the introduction, the third article will explore the major transformations that eaux-de-vie undergo during barrel aging, to better understand and anticipate the effects of rising temperatures in storage cellars
I would like to thank the following spirits experts for their contribution to the writing of this article:
Ludwig VANNERON, Marc GIBOULOT, Thierry ARCHEREAU
ANNEX 1: Passage Patterns of Key Volatile Compounds in Cognac-Style Distillation
Legends: (a) First distillation – (b) Second distillation
ANNEX 2
This table summarizes, for each compound family, its origin, passage behavior during distillation, and organoleptic impact in an eau-de-vie. It also provides key insights into concentration ranges necessary to obtain an eau-de-vie considered free of major defects.
Reminders:
– The origins of these compounds in fermented products are summarized in the synthesis table in the annex of the article on volatile compounds from fermentation: Consequences of Climate Change on the Quality and Stability of Spirits – Part 1.
– The recommended maximum concentrations in freshly distilled eaux-de-vie vary significantly depending on the type of spirit to be produced. If needed, consult an expert to refine the appropriate concentration ranges.
ANNEX 3: Main organoleptic descriptors of Eaux-de-Vie and key volatile compounds that Mmy correlate with these descriptors
The shaded cells highlight the possible correspondences between the organoleptic descriptors of eaux-de-vie and volatile compounds.
(*) Compounds requiring specific analyses beyond routine direct injection gas chromatography with FID detection. See the section dedicated to this analytical technique in the blog article: Consequences of Climate Change on the Quality and Stability of Spirits – Part 1 or click directly here: GC-FID.
Bibliography
[1] REGULATION (EU) 2019/787 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 17 April 2019
“on the definition, designation, presentation, and labeling of spirit drinks,…”
[2] “From Vine to Cognac” – R. Cantagrel, B Galy – Tiré du livre Fermented Beverage Production – Second edition, 2003, édité par Andrew G.H. Lea et John R. Piggott.
To learn more about:
– The principles of distillation: “Distillation des mélanges eau-alcool” – Revue des œnologues N° 106, Martine DECLOUX.
– Cognac distillation: “Etude chimique de la distillation du Cognac” – Bulletin de l’Union des physiciens – Vol. 96, 2002, Jérôme SOURISSEAU.
– The influence of sulfur dioxide and lees on the quality of pot-distilled Brandy: article taken from the book by Alain BERTRAND ” Les eaux-de-vie traditionnelle d’origine viticole »- LAVOISIER – 27/07/2007 – Chapitre 7 – Maria Soleda JURADO, Belen PUERTAS et al.
– The effect of copper on the quality of spirits: “Dimethyl sulphide and the sensory characteristic defect of caçacha distilled in the absence of copper” du livre Distillated spirits – Tradition and Innovation – Chapter 31 – J.B. Faria, V. Ferreira, R. Lopez and J. Cacho.
– Classification of the most common defects in spirits and preventive measures: “Les défauts dans les eaux-de-vie”, ACW 2009, Feuille d’information 7 , Sonia Petignat-Keller, ACW Extension Destillate.
– Long-chain fatty acid ester content in Armagnac spirits: article taken from the book by Alain BERTRAND ” Les eaux-de-vie traditionnelle d’origine viticole” – LAVOISIER – 27/07/2007 – Chapitre 8, Eric HERVE, Marie-Claude SEGUR et Alain BERTRAND.
– The importance of controlling outflow temperatures in pot still distillation: “DISTILLATION ET MAITRISE DES TEMPERATURES DE COULAGE ” – Le Paysan Vigneron 26 juin 2009 .
– The challenges of distillation on the aromatic profile of pot-distilled whisky: se référer au « Livre de Chai – LA DISTILLATION DANS LA PRODUCTION DE WHISKY » de la Maison LINETI rédigé par Magali PICARD.
– Aromatic compounds of traditional white rum: “Nature, propriétés sensorielles et voies de formation” – – Ind. Alim. Agr. 124 (7/8) 20-29 (2007), Julie Coustel, Pierre Giampaoli, Martine Decloux.
– The quality of fruit brandies in relation to the quality of the raw material (plums, peaches, apricots): “Elaboration et connaissance des spiritueux – Recherche de la Qualité, Tradition et Innovation” – Roger CANTAGREL – Edition BNIC – 1er Symposium international de Cognac du 11 au 15 mai 1992, p234, R. CAMPEANU, MARA JONESCU, VALERIA IONITA, I GAVRIILESCU.
– Volatile compounds in cider brandies: “Elaboration et connaissance des spiritueux – Recherche de la Qualité, Tradition et Innovation” – Roger CANTAGREL – Edition BNIC – 1er Symposium international de Cognac du 11 au 15 mai 1992, p355, “Estimation de la composition d’une eau-de-vie de cidre par analyse rapide du cidre de distillation”, S. LESMELE, F. DOREY, S. LE GUENNEC, JM. LE QUERLER, J.F. DRILLEAU.
– Volatile compounds in Tequila: “Flavor and Chemistry of Wine and Other Alcoholic Beverages” – p243. Pedro A. Vasquez-Landaverde, Miriam G. Rodriguez-Olvera.
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