Young Wines Research Articles

The Wisdom of Bacchus: Emblematic, Iconographic and Literary Allusions in the Hermitage Painting by P. P. Rubens

The painting “Bacchus” by Peter Paul Rubens (State Hermitage Museum, St Petersburg) has frequently attracted the attention of both local and foreign researchers. In this article, we question the interpretation of the painting as a simple allegory of the autumn grape harvest and the celebration of production of young wine. Bacchanalian subjects since Antiquity have been loaded with additional meanings associated with regeneration and creative potentials. The latter aspect was picked up and developed by Renaissance artists. Rubens followed often that tradition. L. D. Davis saw in the Hermitage painting a metaphor of the creative method of the Flemish painter, who trusted intuitive impulses more than rigid rules. We share partially this point of view, but we propose to consider the named work in a broader sense than that scholar did. It seems to us that Rubens presented in “Bacchus” his allegorical self-portrait, emphasizing his love of life and his philosophical emancipation. Thus, the Flemish artist expressed his opposition to moralizing and short-sighted opinions in contemporary culture and his desire to return to the breadth of the Renaissance vision. As a consequence, the allusions contained in his painting to “The Andrians” by Titian, some emblems by Andrea Alciato, as well as the new Rubens interpretation of Comus, an ancient character, which John Milton used in his didactic mask a few years before the creation of Hermitage work, — don’t seem accidental. The portly Bacchus in the painting is presented as the lord of earthly diversity and boundless abundance, at the same time he is a wise mentor-judge, indicating how to properly handle all this wealth open to human race. The concept of the boon as the right disposal of freedom and desires, reflected in iconographic system of the Hermitage painting, fits with the ideas of Plato’s dialogue “Feast”.

Chemometric Differentiation of White Wines from a Low-Aromatic Grape Obtained by Spontaneous Fermentation, Enriched with Non-Saccharomyces, or with a High-Glutathione-Producing Saccharomyces Yeast

This work focuses on the establishment of analytical and sensory differences between young wines obtained from the same grape must fermented using different strategies. The main purpose is to provide winemakers with objective criteria to help them to choose the best fermentation method to obtain the desired wine characteristics. The effects of four strategies were tested: a spontaneous fermentation with wild yeasts (WYs) and the addition of starter cultures of Lachancea thermotolerans (LT), Metschnikowia pulcherrima (MP), and a Saccharomyces cerevisiae strain that is an overproducer of glutathione (SC) in different batches of the same must of the Pedro Ximénez white grape. The analytical results obtained show as the LT wine has the highest glutathione content, while the lowest ethanol concentrations. The use of chemometric tools applied to the volatile compounds allowed to differentiate the four wines by a principal component analysis (PCA) and the identification of 27 key compounds. The four wines did not show statistical differences in their smell or taste attributes and only the LT wine was visually differentiated from the rest.

Role of amino acids in flavor profiles and foam characteristics of sparkling wines during aging

As sparkling wine ages, a well-balanced amino acid composition can enrich its flavor profiles and achieve an optimal state for foam characteristics. This study aimed to determine the influence of amino acids on the flavor profiles and foam characteristics of white and rosé sparkling wine. The concentrations of amino acids and aroma compounds were determined via liquid chromatography–mass spectrometry (LC–MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Correlation analysis and multiple linear regression (MLR) models were employed for further analysis. It revealed that the content of amino acids (except for proline) in both sparkling wines decreased with aging (11–23%). Ethyl octanoate had the largest odor activity value (OAV) value in both wines, but its content decreased with aging. The foam parameters of both sparkling wines decreased with increased aging duration, leading to changes in effervescence-related taste traits. Correlation analysis showed that most amino acids positively correlated with ethyl octanoate and foam characteristics, whereas the foam parameters did not increase along with the protein concentrations. Furthermore, the MLR analysis emphasized that amino acids had a greater impact on foam characteristics than volatiles. This study provides guidance for the production of high-quality sparkling wines.

Shaping the chromatic characteristics of red wines by using biofilm-detached cells of Starmerella bacillaris strains

The aim of this study was to evaluate the effects of 10 Starmerella bacillaris strains inoculated as planktonic or biofilm-detached cells on the chromatic characteristics of Montepulciano d’Abruzzo wine. Wines inoculated with biofilm-detached cells of St. bacillaris were characterized by a higher content of glycerol and viable yeast cells and a lower content of ethanol than those obtained with planktonic cells. Pyruvic acid content ranged from 45.99 mg/L to 48.19 mg/L and from 41.13 mg/L to 45.9 mg/L in wines fermented with biofilm-detached and planktonic cells, respectively. Wines obtained with biofilm-detached cells showed levels of anthocyanins ranging from 506.8 mg/L to 659.9 mg/L, while those fermented with free cells of St. bacillaris ranged from 518 mg/L to 612.6 mg/L. Similarly, the content of polyphenols was higher in wines inoculated with biofilm-detached cells. The different amounts of these compounds resulted in differences in the wine's color. Wines obtained with biofilm-detached cells of St. bacillaris had lower b* and h* values than those obtained with planktonic cells. These wines also showed higher a* values, indicating the presence of a stronger red color than the others, and lower clarity (L*). Moreover, the data obtained highlighted that it is possible to predict the color of young wines from must measurements. Further studies will be done to evaluate the role of other non-Saccharomyces yeasts, grown under different aggregation states, in the definition of wine color.

국내 육성 포도 품종 아그데 적포도주 품질 특성

This study aimed to investigate the wine properties of new Korean grape cultivar Ageude. To this end, wine was produced using five grape cultivars including Campbell Early and Muscat Bailey A, which are commonly used for winemaking in Korea and Pinot Meunier and Gamay, which are European wine grape cultivars. We conducted a comprehensive analysis of wine quality properties, color, and phenolic compounds and compared the variations observed among these cultivars. The pH and total acid contents were in the ranges of 3.75-4.57 and 0.39-0.58%, respectively. Specifically, the total acid content of Ageude was 0.47% which was not high, when compared to those of other wines. However, the soluble solid content was 7.85 °Brix, which was higher than those of the other wines. In terms of color, the redness, color intensity, and hue values were all considerably high. Moreover, the total phenolic content and total anthocyanin content of Ageude were notably higher than those of the other cultivars. However, it is worth noting that proanthocyanidin was not detected. Based on these findings, Ageude is an excellent cultivar for producing red wine, owing to its high total anthocyanin content and redness due to the absence of proanthocyanidin, it is more suitable for producing short-term aging wine rather than long-term aging wine.

Effect of Maturation with American Oak Chips on the Volatile and Sensory Profile of a Cabernet Sauvignon Rosé Wine and Its Comparison with Commercial Wines

Rosé wines are commonly consumed as young wines mainly due to their freshness and fruity character. Nevertheless, in recent years a new market looking for alternatives to traditional wines has emerged. Considering this, the study of the volatile and sensory profiles of a varietal rosé wine aged with oak chips was carried out. Two Cabernet Sauvignon rosé wines were made: one was maturated with oak chips and the other without. Both wines were physicochemically characterized. Then, their volatile and sensory profiles were analyzed, also including two commercial wines. The results showed that the produced wines complied with Mexican regulations. Also, they showed greater relative areas in compounds such as ethyl (E)-2-hexenoate, ethyl heptanoate, ethyl nonanoate, ethyl 3-nonenoate, β-citronellol, (±)-trans-nerolidol, and β-damascenone. In their sensory profile, they were mostly related to attributes such as berries, prune, bell pepper, and herbaceous notes. Among the compounds related to barrel maturation, only cis-oak-lactone was identified in the rosé wine matured with chips. However, it was associated with vanilla, woody, smoky, and spicy attributes. According to the results, the maturation of rosé wines with oak chips could be a good alternative to provide them with unusual notes and thus offer new alternatives to traditional and new wine consumers.

A Molecular Toolbox to Identify and Quantify Grape Varieties: On the Trace of "Glera".

A pillar of wine authenticity is the variety/ies used. Ampelographic descriptors and SSR markers, included in several national and international databases, are extensively used for varietal identification purposes. Recently, SNP markers have been proposed as useful for grape varietal identification and traceability. Our study has been directed toward the development of a molecular toolbox able to track grape varieties from the nursery to the must. Two complementary approaches were developed, exploiting SNP markers with two different technologies, i.e., a high-throughput platform for varietal identification and a digital PCR system for varietal quantification. As proof-of-concept, the toolbox was successfully applied to the identification and quantification of the "Glera" variety along the Prosecco wine production chain. The assays developed found their limits in commercial, aged wines.

Impact of harvest date on aroma compound composition of Merlot and Cabernet-Sauvignon must and wine in a context of climate change: a focus on cooked fruit molecular markers

Choice of harvest date can modulate the aroma intensity of herbaceous/vegetal, fresh fruit and cooked fruit nuances, thus helping the winemaker to produce wine of different styles and balance. Relationships between the sensory attributes and aroma compounds of Merlot and Cabernet-Sauvignon grapes that were harvested sequentially and the resulting wines were evaluated for two vintages: 2012 and 2014. The fine-tuning of the harvest date modulated the aromas of the young wine and impacted the intensity of the cooked fruit aromas for both Merlot and Cabernet-Sauvignon. No correlation was observed between the must and wine in terms of the intensity of the cooked fruit aroma. In order to observe an impact on the intensity of the cooked fruit aroma it was necessary to delay the harvest date of Cabernet-Sauvignon by 4 to 12 days in 2012 and 2014 respectively. This value was 7 days for Merlot wines (2014 vintage). Furanones, lactone and ketones were well correlated with the perceived intensity of the cooked fruit aroma in the young wine. In addition, the highest concentrations of γ-nonalactone, 3-methyl-2,4-nonanedione, massoia lactone and furaneol were detected in Merlot wines made using late-harvested grapes. At the measured concentrations, these compounds can explain the aroma of cooked fruit detected in the red wines. Similar results were obtained for the Cabernet-Sauvignon wines made from grapes from a later harvest. The volatile compounds produced from the lipoxygenase pathway in the grapes were putatively involved in the evolution of the aroma of the red wines from sequential harvest dates, opening up the possibility of managing aroma profiles through harvest date decisions. These findings are important, as the identification of measurable key chemical parameters in grapes could provide grape growers and winemakers objective indicators for predicting final wine style and quality.

Evaluation and Comparison of Dermo-Cosmetic Activities of Three Oak Species by Targeting Antioxidant Metabolites and Skin Enzyme Inhibitors.

The two main species, sessile oak (Quercus petraea Liebl.) and pedunculate oak (Quercus robur L.), predominant in French forests, are mainly used for aging wines and spirits; however, the potential of oak wood extract as a source of natural antioxidants, due to its high polyphenol content, could be more widely exploited. This study focuses on three oak species, the two that are well-known, namely, sessile and pedunculate oak, and a third that has seldom been described and valorized, namely, pubescent oak (Quercus pubescens). Water extracts of these three species were fractionated by semi-preparative HPLC. The antioxidant activities of crude extracts and fractions were measured by colorimetric and enzymatic tests. The anti-elastase and anti-collagenase activities of the extracts and their fractions were also evaluated. In parallel, samples were analyzed by UHPLC-HRMS to correlate the activity with the molecular composition using molecular networks. The results obtained for the total extract of the three species were compared to determine if the activity depended on the species. The results within the same species were also compared to highlight which fraction and, therefore, which molecular family was involved in the activity of the total extract. The various antioxidant tests showed good activity of the total extract for the three species of oak and a very good anti-collagenase activity. The antioxidant activity of oak extract has already been proven in the literature and this is correlated with its richness in polyphenols. This study shows that each molecular family of the extract contributes to the activities of the total extract. Oak extract can be used to neutralize the ROS produced during oxidative stress and to prevent the degradation of collagen and elastase during skin aging. Its complementary properties make oak extract a valuable ingredient to act against skin aging.

Metagenomic analysis of the relationship between the microorganisms and the volatiles' development in the wines during spontaneous fermentation from the eastern foothills of the Ningxia Helan mountains in China.

The natural fermentation of multispecies microbial communities is responsible for unique flavors of winery regions of the eastern foothills of the Ningxia Helan Mountains in China. However, the participation of different microorganisms in the metabolic network for the development of important flavor substances is not clearly defined. Microbial population and diversity on different fermentation phases of Ningxia wine were analyzed by metagenomic sequencing approach. Gas chromatography-mass spectrometry and ion chromatography were used to identify flavor components, and 13 esters, 13 alcohols, nine aldehydes and seven ketones were detected in volatile substances with odor activity values > 1, and eight organic acids were detected as important flavor components in young wine. Thus, 52 238 predicted protein-coding genes from 24 genera were identified in the Kyoto Encyclopedia of Genes and Genomes level 2 pathways of global and overview maps, and the genes were primarily involved in amino acid metabolism and carbohydrate metabolism. Major microbial genera (Saccharomyces, Tatumella, Hanseniaspora, Lactobacillus, and Lachancea) were closely related to self-characteristic compound metabolism and further contributed to wine flavor. This study clarifies the different metabolic roles of microorganisms in flavor formation during Ningxia wine spontaneous fermentation. Saccharomyces, dominant fungi involved in glycolysis and pyruvate metabolism, produces not only ethanol but also two important precursors, pyruvate and acetyl-CoA, which are necessary for the tricarboxylic acid cycle, fatty acid metabolism, amino acid metabolism, and flavor formation. Lactobacillus and Lachancea, dominant bacteria involved in lactic acid metabolism. Tatumella, dominant bacteria involved in amino acid metabolism, fatty acid metabolism, and acetic acid metabolism to produce esters in the Shizuishan City region samples. These findings provide insights into the use of local functional strains to generate unique flavor formation, as well as improved stability and quality, in wine production. © 2023 Society of Chemical Industry.

The impact of dosage sugar-type and aging on Maillard reaction-associated products in traditional method sparkling wines

Liqueur d’expedition (dosage) is a final sugar addition made to sparkling wine which determines the sweetness and balance of the finished product. In the present study, the influence of dosage sugar composition on Maillard reaction-associated products and precursors in traditional method (bottle-fermented) sparkling wines was evaluated over 18-months of storage in climate-controlled cellar conditions (14 °C, 70 % relative humidity). Evaluated dosage sugar-types included glucose, fructose, cane-derived sucrose, beet-derived sucrose, maltose, and Must Concentrate Rectified (MCR) Sucraisin®, which were compared to a zero dosage (no sugar added) control. Maillard reaction-associated products were quantified by headspace solid-phase microextraction coupled to gas-chromatography-mass spectrometry (HS-SPME-GC/MS), and precursors including sugars and amino acids, were measured by enzymatic assay and proton (1H) nuclear magnetic resonance (NMR) spectroscopy, respectively. Partial least squares discriminant analysis (PLS-DA) was used to effectively discriminate between wines based on aging duration but did not adequately separate wines treated with different dosage sugar-types. Decreases in alanine and glycine were observed after 18-months of cellar aging, suggesting that Maillard reaction product formation may be partially related to their depletion. Benzaldehyde and ethyl-3-mercaptopropionate were identified as discriminatory Maillard reaction-associated compounds when comparing 0- and 18-month aged wines, with benzaldehyde increasing and ethyl-3-mercaptopropionate decreasing over the aging period. This research contributes to an increased understanding of Maillard reaction pathways in the unique low-temperature and low pH sparkling wine matrix and establishes the relatively greater effect of aging duration compared to dosage sugar-type on the formation of Maillard reaction-associated products. The combined application of HS-SPME-GC/MS and 1H NMR based metabolomics presents new insights into the chemical composition of sparkling wines during aging.

Kinetics of oxygen consumption, a key factor in the changes of young wines composition

The oxygen that a wine receives during the winemaking process defines its properties. The aim of this work was to evaluate the oxygen consumption capacity of wines and its influence on the modification of their composition. This preliminary work evaluated the changes after 3 months in the chemical composition of twenty-seven Spanish commercial red, white and rosé wines after their air saturation and oxidation process at 35 °C for 7 days. All the wines studied were high oxygen consumers, while the white and rosé wines showed greater variability according to their chemical composition. Wines that consumed a lot of oxygen did so quickly or slowly, while wines that consumed little oxygen did so slowly. All the wines showed a significant decrease in ethyl esters of straight-chain fatty acids (50–58%), ethyl esters of branched-chain fatty acids (48–56%) and alcohol acetates (34–65%) content, and a significant increase in Strecker aldehydes (24%) because of oxygen consumption. This paper presents a preliminary approach to determine the oxidation tendency of different wines showing the importance of controlling the winemaking processes that can increase oxygen availability and of establishing the minimum appropriate level of free sulfur dioxide.

Identification of Oak-Barrel and Stainless Steel Tanks with Oak Chips Aged Wines in Ningxia Based on Three-Dimensional Fluorescence Spectroscopy Combined with Chemometrics.

With the increased incidence of wine fraud, a fast and reliable method for wine certification has become a necessary prerequisite for the vigorous development of the global wine industry. In this study, a classification strategy based on three-dimensional fluorescence spectroscopy combined with chemometrics was proposed for oak-barrel and stainless steel tanks with oak chips aged wines. Principal component analysis (PCA), partial least squares analysis (PLS-DA), and Fisher discriminant analysis (FDA) were used to distinguish and evaluate the data matrix of the three-dimensional fluorescence spectra of wines. The results showed that FDA was superior to PCA and PLS-DA in classifying oak-barrel and stainless steel tanks with oak chips aged wines. As a general conclusion, three-dimensional fluorescence spectroscopy can provide valuable fingerprint information for the identification of oak-barrel and stainless steel tanks with oak chips aged wines, while the study will provide some theoretical references and standards for the quality control and quality assessment of oak-barrel aged wines.

A Strategy for Differentiating Oak Barrel Aged and Non-Oak Barrel Aged Wines by Using UHPLC–HRMS Combined with Chemometrics

The time involved and the high economic cost of using oak barrels to age wines have led to a significant price difference compared to non-oak barrel aged wines and may lead to some fraudulent sales in the market. In this study, an untargeted metabolomic strategy was developed to detect the metabolite composition of oak barrel aged and non-oak barrel aged wines in both positive and negative ion modes by using UHPLC–HRMS combined with the recently developed chemometric method AntDAS. The results of partial least squares discrimination analysis (PLS-DA) showed that the samples were characterized into two categories. Finally, 51 compounds were identified in positive ion mode, while 26 compounds were identified in negative ion mode. The results indicate that combining UHPLC–HRMS with AntDAS can reveal the material basis of wines and has excellent potential to differentiate between oak barrel aged and non-oak barrel aged wines.

Study of the influence of fermentation conditions on the content of aroma-forming substances in young red wines

One of the main requirements for young wines is preservation the qualities of the grapes, including the bright varietal aroma characteristic of essential oils concentrated in the grape skins. At the same time, in the formation of the aroma of wine, substances synthesized by the enzyme systems of yeast cells are involved in the process of alcoholic fermentation. The main factors influencing the formation and ratio of aroma-forming substances in wine are the composition of the substrate, the race of yeast and the conditions for the fermentation process. Therefore, studies of the influence of the conditions of the fermentation process in the production of young red wine materials on the chemical composition of the aroma-forming components of wine are relevant. The analysis of the data obtained indicates the influence of the methods of carrying out the alcohol process on the content of aroma-forming compounds: aldehydes, ketones, higher and polyhydric alcohols, esters and fatty acids. It has been shown that the fermentation of the pulp wort, unlike carbon dioxide maceration, leads to a greater accumulation of oxidation products: acetaldehyde, acetoin and diacetyl, and also contributes to a higher content of higher alcohols. Under conditions of carbon dioxide maceration, a significant accumulation of aromatic alcohol – phenylethanol occurs. The conducted studies have shown that the use of carbon dioxide maceration using the Moldova grape variety generally has led to a significantly lower formation of oxidation products of both wort components and fermentation products. The additional introduction of carbon dioxide contributed to a decrease in the RH potential of the fermenting wort, which stimulated the accumulation of substances in a reduced form. At the same time, the content of esters in the case of artificial maceration is higher than under normal conditions, which indicates more intense enzymatic esterification reactions.It has been established that carbon dioxide maceration, in comparison with the classical processing of grapes, contributes to a greater formation and extraction of favorable aromatic components, and the additional introduction of carbon dioxide enhances this process.

Chemical Stability of Thiol and Flavanol Sulfonation Products during Wine Aging Conditions.

Bisulfite (HSO3-) is the predominant form of sulfur dioxide, present as free and bound to wine relevant electrophiles under wine acidic pH. While sulfonation reactions of flavanols and thiols have been recently reported as key for wine preservation against oxidation, the transient mechanisms and physicochemical parameters responsible for that remain unknown. In the present study, sulfonation reaction kinetics of thiols and flavanols were monitored under simulated wine aging conditions. The reaction products were then characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and their chemical stability during time was determined by 1H NMR spectroscopy. Thiol and flavanol sulfonation reaction yields were both promoted by the presence of iron and oxygen, while their chemical stability was confirmed under the same conditions. The sulfonation derivatives of epicatechin and cysteine were synthesized and quantified in young and aged wines. Higher concentrations were reported for both metabolites in older wines, indicating their participation on the strongly bound sulfur dioxide fraction. These findings offer new prospects for more precise use of sulfur dioxide in winemaking.

Microbiome composition and dynamics while grapes turn to wine

Microbial composition and activity were recorded during preparation of Pinot blanc (“Rulandské biele”) from one vineyard during the years 2018, 2019, and 2020. Both fungi and bacteria are important for primary fermentation and malto-lactic fermentation, therefore total DNA and total RNA were isolated, and genes for 16S and 28S rRNA were amplified to determine both bacterial and yeast profiles. Four phases of wine production were selected for testing. We tested the initial grape juice right after crushing the grapes, must ~2-3 days post inoculation, actively fermenting must and finally – young wine before filtration. We experimented on 3 batches with addition of selected strains of Lachancea thermotolerans, Metschnikowia pulcherrima and commercial strains of Saccharomyces cerevisiae. The most apparent was seasonality and the effect of weather at given year. Naturally occurring yeast Hanseniaspora was detected alongside major players like S. cerevisiae. The most dominant bacterial genera were Gluconobacter, Komagataeibacter and Acetobacter. We were able to detect contaminating coliform bacteria as a result of unexpectedly warm and humid conditions during the harvest in 2018. This method even detected plant pathogens Penicillium, Botrytis, and Alternaria in some samples, and might be indicative of the health of a vineyard.

Aging of Malbec Wines from Mendoza and California: Evolution of Volatile Composition

<h3>Abstract</h3> <h3>Background and goals</h3> The search for strategies to improve the quality of Argentine Malbec wines has led to experimentation with production of wines that achieve superior sensory properties after prolonged bottle aging. During aging, a series of complex oxidation-reduction and polymerization reactions occur. These reactions, responsible for changing the sensory aspects of wines, can be influenced by a variety of factors (terroir, winemaking practices, storage conditions, etc.). Thus, understanding the chemical processes that take place during bottle aging could significantly impact the enology industry. This work evaluates the evolution of aromatic profiles over time in Malbec wines from Mendoza and California. <h3>Methods and key findings</h3> Wines from Mendoza and California were obtained under standardized conditions. Determination of volatile profiles was carried out on young wines by gas chromatography-mass spectrometry and, subsequently, after seven years of aging. The effect of time and region on volatile profiles was investigated. The aging time showed a significant effect on the aromatic composition. While the profiles obtained after seven years were less diverse than at bottling, they retained a significant number of desirable volatile compounds. Additionally, the volatile profiles of the aged wines still permitted differentiation of samples by country of origin. <h3>Conclusions and significance</h3> The information obtained enabled us to assess the evolution of aromatic profiles during bottle aging of Malbec wines from Mendoza and California, and could be useful in decision-making regarding the blending, marketing, and storage of these wines.

Variations in physicochemical characteristics, antioxidant activity, phenolic and volatile profiles, and sensory attributes of tea-flavored Chardonnay wine during bottle aging.

A novel Chardonnay wine flavored with either green tea or black tea was subjected to bottle aging for 9 months, and the physicochemical properties, antioxidant capacity, total phenolic content, volatile content and sensory properties were monitored. There were 272 phenolic and non-phenolic compounds characterized in the aged Chardonnay wines, including newly formed 9, 1, 3 and 8 phenolic compounds and 10, 6, 1 and 6 non-phenolic compounds after aging for 1, 3, 6 and 9 months, respectively. For all the aged wines, catechin was determined as the most abundant phenolic compound, and epigallocatechin mainly contributed toward the antioxidant power. A total of 54 volatile compounds were identified in the aged Chardonnay wines, including 17 odor-active compounds. The aging process diminished floral and fruity odors, but intensified green odor. The consumer study revealed the highest consumer liking for 1% (w/v) black tea infused wine. This study revealed the quality and bioactivity of this novel flavored wine type during aging which is critical to understand the shelf-life and functionality of the product.

Influence of the use of sulfur dioxide, the distillation method, the oak wood type and the aging time on the production of brandies

Brandies are spirits produced from wine spirit and wine distillates. The original wines selected to be distilled to produce the wine spirits as well as the distillation method used determine, to a large extent, the organoleptic characteristics of the final products. The young wine spirits evolve during their aging in oak casks, this being another key stage that affects the chemical and sensorial characteristics of the final brandy. In this work, seven different brandies have been studied. They were obtained from wine produced with and without the addition of sulfur dioxide, during their fermentation, using different distillation methods (single, double or serial distillation using pot stills and continuous column distillation) and aged for 14 or 28 months in three different types of oak wood (Quercus alba, Quercus robur and Quercus petraea) previously toasted to two different grades (medium or light).The use of unsupervised pattern recognition methods (HCA and FA) determined that the addition of sulfur dioxide during the fermentation of the base wine has a major influence on the aromatic and phenolic profile of the aged distillates. On the other hand, by means of supervised pattern recognition methods such as LDA and ANNs, the most significant variables that would allow to discriminate between the classes of brandies identified in the study were evaluated. Thus, the results obtained should cast some light on the most significant variables to be taken into account regarding Brandy production processes if a better control over these production processes is to be achieved, so that more exclusive and better quality products are obtained.