Wine Aging Research Articles

Microbial Communities of Flor Velums and the Genetic Stability of Flor Yeasts Used for a Long Time for the Industrial Production of Sherry-like Wines

Flor yeast strains represent a specialized group of Saccharomyces cerevisiae yeasts used for the production of sherry-like wines by biological wine aging. We sequenced the genome of the industrial flor yeast strain I-329 from a collection of microorganisms for winemaking “Magarach” and the metagenomes of two flor velums based on this strain and continuously maintained for several decades. The winery uses two processes for the production of sherry-like wine: batch aging and a continuous process similar to the criaderas–solera system. The 18S rRNA gene profiling and sequencing of metagenomes of flor velums revealed the presence of the yeasts Pichia membranifaciens and Malassezia restricta in minor amounts along with the dominant S. cerevisiae I-329 flor yeast. Bacteria Oenococcus oeni and Lentilactobacillus hilgardii together accounted for approximately 20% of the velum microbiota in the case of a batch process, but less than 1% in the velum used in the continuous process. Collection strain I-329 was triploid for all chromosomes except diploid chromosomes I and III, while the copy numbers of all chromosomes were equal in industrial velums. A comparative analysis of the genome of strain I-329 maintained in the collection and metagenomes of industrial velums revealed only several dozens of single nucleotide polymorphisms, which indicates a long-term genetic stability of this flor yeast strain under the harsh conditions of biological wine aging.

Diverse phenolic responses of six varietal wines (Vitis vinifera L.) throughout ageing in contact with a single type of oak barrels

SummaryBarrel ageing is a critical process in wine industry since it produces substantial changes in the chemical composition of wines. The transfer of polyphenols from wood to wine would be influenced by various factors including wood characteristics and storage conditions. The role of the wine matrix in the extraction/modification of polyphenols during wine ageing has been scarcely studied. The objective of this study was to characterise and compare the phenolic composition of six varietal wines (Carménère, Cabernet Franc, Malbec, Petit Verdot, Sangiovese and Tempranillo) during ageing in a single type of oak barrel aiming to learn about the role of the variety on the ageing process. Wine sampling was performed at 3‐month intervals for 1 year. Polyphenol profiles were analysed using spectrophotometric and HPLC‐DAD methods. The study showed that the effect of oak wood ageing on the phenolic composition of wines is highly influenced by the grape variety. Thus, different polyphenol‐associated chemical parameters of oak‐aged wines would be affected by chemical properties of the varietal wines that are present prior to barrel ageing.

Sanitisation of wine-ageing barrels using near Ultraviolet radiation

The ageing of wine in oak barrels represents a critical stage in winemaking at which product alteration can occur due to bacteria, yeasts or fungal growth. The control of microorganisms, such as yeasts of the Brettanomyces genus (Guzzon et al, 2011) and acetic acid bacteria (Kocijan et al, 2021), is of great importance, since the alterations that they can cause in wine can be very serious and cause great economic losses.

Toasted Vine Shoots as an Alternative Enological Tool. Impact on the Sensory Profile of Tempranillo Wines during Bottle Aging.

The use of toasted vine shoots (SEGs) as an enological tool is a new practice that seeks to improve wines by differentiating between them and encouraging sustainable wine production. The sensorial impact during bottle aging of wines treated with SEGs is a key factor to consider. This paper studies the influence of SEGs on Tempranillo wines treated with their own SEGs in two different doses (12 and 24 g/L) at two differences moments (during alcoholic fermentation and after malolactic fermentation) throughout 1 year of bottle aging. The results indicate that addition moment is the factor that most affects the evolution of sensorial descriptors. The greatest evolution in the wines was observed during the first 4 months, wherein improved integration of the notes related to addition of SEGs occurred. A reduction in the perception of dryness and bitterness was observed in the treated wines, therefore, SEGs could be considered accelerators to eliminate these initial sensations from wines.

Characterization of the Aroma Profile of Commercial Prosecco Sparkling Wines

In this work, the aromatic characterization of commercially available Prosecco wines with a price range between EUR 7 and 13 was carried out. These wines came from three different areas of origin: Valdobbiadene, Asolo and Treviso. Seventy volatile compounds were identified and quantified in the wines. Quantitatively, the wines were mainly characterized by compounds of fermentation origin (alcohols, acids, esters), and C6-alcohols, and to a lesser extent, terpenes, low molecular weight volatile sulfur compounds (VSC), and benzenoids. To determine their impact on the aroma of Prosecco wine, the respective OAVs were calculated. The molecules with higher OAV were ethyl hexanoate, isoamyl acetate, and β-damascenone. More generally, esters, responsible for fruity notes, seemed to play a major role in the aroma of Prosecco wine. Investigation into the possible effect of different production zones indicated 16 significantly different compounds accounting for differences between the various areas of origin of the wines, being mostly VSC, esters and C6-alcohols. A sensory evaluation through a sorting task highlighted the formation of clusters; wine samples were divided into two main groups partially attributable to the areas of origin. From a chemical point of view, cluster A was richer in esters, while cluster B had, on average, higher concentrations of compounds associated with wine aging such as cyclic terpenes, norisoprenoids (TDN and vitispirane), and VSC.

White Wine Antioxidant Metabolome: Definition and Dynamic Behavior during Aging on Lees in Oak Barrels.

White wines' oxidative stability is related to a flow of chemical reactions involving a number of native wine compounds comprising their antioxidant metabolome. By applying the combination of powerful and modern analytical approaches (EPR, DPPH, and UPLC-qToF-MS-based metabolomics), we could define wine antioxidant metabolome as the sum of molecular antioxidant markers (AM) characterized by their radical scavenging (AM-RS) and nucleophilic (AM-Nu) properties. The impact of on-lees barrel aging of chardonnay wines on the antioxidant metabolome was studied for two consecutive vintages. The identification of wines' antioxidant metabolome allows for a detailed understanding of the transient chemical interplays involved in the antioxidant chemistry associated with well-known antioxidants and opens an avenue towards personalized winemaking. The present study gathers for the first time the dynamics of wines' antioxidant metabolome during on-lees aging. Monitoring the variations of the wine antioxidant metabolome can provide an avenue to better control the winemaking process using the knowledge of how to optimize the wine aging potential.

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.

Hydrogen Sulfide Formation in Canned Wines Under Long-Term and Accelerated Conditions

<h3>Background and goals</h3> Wines in aluminum beverage cans (“canned wines”) are a rapidly growing packaging segment due to several factors, including convenience and sustainability advantages. However, canned wines have higher concentrations of hydrogen sulfide (H₂S; “rotten egg”) than wines in glass packaging. It was hypothesized that wine composition and liner selection affect H₂S formation in canned wines. <h3>Methods and key findings</h3> Commercial wines (n=10) were stored in either glass or aluminum beverage cans with one of three liners for up to 32 weeks. Wines stored in glass showed negligible H₂S production after 32 weeks. Wines stored in acrylic lined cans produced up to 1307 μg/L H₂S (median = 162 μg/L) within 8 weeks. Wines stored in BPA epoxy cans produced less H₂S (maximum = 51.8 μg/L median = 11.8 μg/L after 32 weeks), with comparable performance observed for BPA non-intent (BPA-NI) epoxy liners. H₂S formation was well-correlated with visible damage to the interior liners, but poorly correlated with dissolved aluminum. H₂S from accelerated aging of wines with lined aluminum coupons (50 ºC, up to 14 d, anoxic conditions) correlated with H₂S produced during long-term aging, but not with H₂S produced by unlined aluminum coupons. Molecular SO2 was best correlated with increased H₂S production in epoxy lined cans during long-term aging of commercial wines, and similar results were observed under accelerated conditions with coupons in a model-wine factorial experiment. <h3>Conclusions and significance</h3> Maintaining low molecular SO2 (less than ~0.4 mg/L) and using epoxy liners (BPA or BPA-NI) appear critical for ensuring low H₂S during long-term can storage up to 8 months. The accelerated aging approach described in this work may be applicable to other corrosive beverages.

Increasing amino acids and biogenic amines content of white and rosé wines during ageing on lees

The presence of biogenic amines in wine is more and more important both to consumers and producers alike, due to the potential threats of toxicity of humans and consequent trade implications. Biogenic amines are formed from amino acids by decarboxylation carried out by various enzymes located in yeasts and bacteria. During ageing of wines on lees, the release of different compounds, especially proteins, peptides, amino acids, breakdown products of yeasts, can impact on the quality of wine. The aim of this study is to describe the evolution of twenty-two amino acids, precursors of seven biogenic amines during ageing on lees for 12 months, respectively 18 months, using 12 commercial maturation products. The number of experimental samples is 26 (V1SB-V13SB, V1BB-V13BB), produced in Iasi vineyard, vintage 2020, from Sauvignon Blanc and Busuioaca de Bohotin grapes variety. Data indicated a major impact of the variables (commercial maturation products, autolysis process and grape variety) on wine’s characteristics. Considerable amounts of some essential amino acids, such as L-alanine, L-leucine, L-lysine, L-valine and L-glutamic acid were found in samples treated with commercial products, which contained significant amounts of mannoproteins, amino acids and vitamins (samples V6SB, V4SB, V5SB, V5BB, V4BB and V6BB). Vitamins and nitrogenous compounds released by autolysis are used as a support in the decarboxylation process, thus forming biogenic amines.

Application of ultrasounds to improve oak aging of white wines

Increasing the efficiency of the release for certain compounds during the maturation of some wines in the presence of oak chips is an important topic for oenology research. This study followed the influence of the use of ultrasound waves with a frequency of 35 kHz on the physicochemical and sensory characteristics of some white wines from Iasi, Romania. Oak chips (1 g/L and 2 g/L, fresh, light, and medium toasted) were added to the Fetească regală and Sauvignon blanc stabilized wines. The samples were kept at a constant temperature of 15oC for 10 and 15 days, respectively. For comparison, 15 mins. ultrasound-treated samples were used. It has been observed that this technique in addition to reducing the aging time, significantly influences the organoleptic characteristics of the treated wines. New ways to continue research to clarify, optimize and streamline the methods of artificial aging of wines have also been identified.

Micro-oxydation of wine in a ceramic vessel with CNT

Wine aging is typically performed using oak barrels. The porosity of the oak wood allows oxygen, which is one of the most important factors in the maturation and ageing of wines, to enter into the barrel in a controlled manner. Even though this is an established method, in has two major drawbacks a) the limited life of the barrels (they can be used up to three times) and b) alcohol evaporation during the ageing process. Our study was inspired by the ancient times when wine was stored in ceramic containers called amphorae. In the present study, ceramic vessels were made of porcelain and investigated as new containers for wine ageing. To create conditions for micro-oxygenation (MOX), the porosity of the porcelain ceramic vessels was modified by adding carbon nanotubes (CNTs) at different concentrations (0.1 to 0.3%). Red wine was stored inside the CNT/ceramic vessels and its total phenols, pH and weight was measured at a period of 5 months. The results showed that there is a potential for creating ageing conditions in porcelain ceramic vessels, as a controlled decrease in total phenols in wine was observed. Specifically, the vessels with a CNTs content of 0.1% showed the least reduction in total phenols, while the vessels with a CNTs content of 0.3% showed the greatest reduction in total phenols. Another advantage is the minimal wine volume reduction observed (0.8–1.8% compared to oak barrels 3–5%).

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.

Organoleptic characterization of wines in contact with oak wood fragments immersed in plasma activated water (PAW)

Oak barrels are a valuable material for wine ageing, although their difficult cleaning and disinfection favours microbiological contamination causing wine quality depreciation. Atmospheric pressure cold plasma is a suitable technique to reduce microbiota, but there is little research on its impact on the nutritional and sensory characteristics of foods. The aim of this study was to analyse the organoleptic characteristics of red wines in contact with plasma-activated waters (PAW) treated wood, of different origins and toasting levels. These red wines were compared with others that had been in contact with two types of control wood; some immersed in distilled water and others subjected to sulphur dioxide combustion. The results showed that oak wood treated with PAW did not cause defects at the olfactory and gustatory level of the red wines, which presented good harmony, sufficient body and balanced fruity and spicy notes, sometimes even superior to those described for red wines in contact with control wood (sulphited or submerged in distilled water). Therefore, the treatment of the wood with PAW did not have a negative impact on the sensory quality of the wines, regardless of the origin and toasting of the wood.

Effects of magnetization with neodymium magnets treatment on blueberry wine ageing

The feasibility of magnetization treatment, using neodymium magnets, for blueberry wine ageing was investigated. Two magnetization ageing devices with different operating modes (M1, circulation between two tanks; M2, single-tank circulation) were used to treat new blueberry wine. Changes in the basic characteristics, phenolic substances, antioxidant capacity, and sensory properties were evaluated. The magnetization treatment induced a faster change in the basic characteristics of the wine compared to that of the control. The magnetized blueberry wine showed higher total phenol content, antioxidant capacity, and more volatile compounds. Sensory evaluation showed that the quality of blueberry wine was improved during magnetization ageing. Moreover, the positive influence of the M1 mode on the aforementioned properties was greater than that of the M2 mode. However, when the treatment time was more than 8 weeks, the antioxidant capacity, color, and sensory evaluation of the magnetized blueberry wine were worse than those of the control. These results proved that magnetization treatment could significantly accelerate the early ageing process of blueberry wine. The effect of M1 on the ageing process was better than M2.

Analytical, Chemometric and Sensorial Characterization of Oloroso and Palo Cortado Sherries during Their Ageing in the Criaderas y Solera System.

Oloroso and Palo Cortado are two types of sherry wines, produced in the Sherry Wine Region in Southern Spain, known as Marco de Jerez, where it is aged following the traditional Criaderas y Solera system. All of them are aged through oxidative ageing, even though the peculiar Palo Cortado Sherry wine is also aged biologically under a veil of flor yeasts in the first stage. Total dry extract, organic acids, aldehydes, esters, higher alcohols and phenolic compounds in these sherry wines evolve during their ageing as a consequence of evaporation and/or perspiration processes, chemical reactions, extraction of compounds from oakwood and microbiological activity. Sherry wines develop their characteristic organoleptic profile during their ageing, as could be proven through their tasting sessions. According to the sherry type, some natural groupings of the wines could be observed after their principal component analysis. Furthermore, by multiple linear regression methods, an important correlation between the parameters that were analyzed and the ageing of each specific wine has been confirmed, which allowed us to establish two different models, each corresponding to the sherry type in question. Only five of the variables that were investigated were required to successfully estimate each wine's age at over 99% confidence. This represents a rather convenient tool for wineries to monitor the ageing of these sherry wines.

Hygrothermal conditions for the aging of red wine from experimental data

Despite the importance of the aging process, there is great disparity in the hygrothermal conditions in which to carry it out. The aim of this work is to propose contrasted data, based on successful cases and millions of experimental data, which can be taken as a reference for the climate control of aging rooms. For this purpose, the hygrothermal environment of 19 red wine aging rooms with multiple construction designs was monitored and statistically characterized. The results showed a great variability in the hygrothermal environment. Frequency histograms and psychometric diagrams revealed the true hygrothermal environment of red wine aging rooms. There were large differences in stability and uniformity depending on the construction design (up to four times). The indoor hygrothermal environment was not kept within the comfort ranges mentioned by a wide list of authors (2–65% of time out of range). A contrasted psychometric diagram establishing monthly comfort intervals and other useful data (stability, uniformity …) were proposed, based on the hygrothermal environment of wineries with quality wines. The results should be a valuable tool for the wine sector, in order to control the evolution of aging, set the programming of air conditioning equipment and simulate the behavior of new wineries.

Industry and academia-a perfect match.

My career developed very differently from those of most academic researchers. After school, I worked for 6 years in industries that employed yeast to manufacture ethanol and beer. At university, I was trained as a microbiologist with very little training in molecular biology. I retrained in 1987 in molecular yeast genetics and focused on genetic engineering of industrial yeasts to minimize the production of spoilage compounds in wine and ethyl carbamate, a carcinogen, in wine. The malolactic yeast ML01 and the urea-degrading yeast were the first genetically enhanced yeasts that obtained US FDA approval for commercial applications. Apart from applied research, I was fascinated by classic molecular yeast genetic studies using sophisticated techniques such as transcriptomics, proteomics, and metabolomics. Doing research at the University of British Columbia was stimulating and exciting, we established a core microarray and metabolomics facility that was used by many scientists at UBC and hospitals in Vancouver. I also established a state-of-the-art Wine Library that was used to study aging of wines produced in British Columbia. Finally, I have been fortunate to know and collaborate with leading yeast scientists who motivated me.

Effect of mannoproteins from different oenological yeast on pigment composition and color stability of red wine

In this work, MP-rich extracts from Saccharomyces and non-Saccharomyces yeasts were obtained by cell sonication and were characterized. The extracts were added to a red wine and color and pigment composition modifications were evaluated by CIELAB parameters and HPLC-DAD-MS, respectively, after cold treatment (to provoke colloidal instability) and storage at room temperature (to accelerate wine aging). Results indicate that the MP-rich extracts showed differences in their composition and in the structure of the MPs depending on the yeast species. They also had different effects on the stability of wine pigments, being the extract obtained from Torulaspora delbrueckii the one that provided the best results, by contributing to the colloidal and chemical stability of the coloring matter. Wines added with this extract showed concentrations of p-coumaroylated and caffeoylated anthocyanins 33.40% higher than the control wine after 4 days of storage at 4 °C.

Influence of Caffeic and Caftaric Acid, Fructose, and Storage Temperature on Furan Derivatives in Base Wine.

The aim of this study was to determine the influence of caffeic and caftaric acid, fructose, and storage temperature on the formation of furan-derived compounds during storage of base wines. Base wines produced from Chardonnay grapes were stored at 15 and 30 °C for 90 days with additions of fructose, caffeic acid, and caftaric acid independently or in combinations. Wines were analyzed following 90 days of storage for: total hydroxycinnamic acids, degree of browning, caffeic acid and caftaric acid concentrations, and nine furan-derived compounds. Caffeic and caftaric acid additions increased homofuraneol concentration by 31% and 39%, respectively, at 15 °C (p &lt; 0.05). Only the addition of caffeic acid increased furfural by 15% at 15 °C (p &lt; 0.05). Results demonstrate that some furan derivatives over 90 days at 15 °C increased slightly with 5 mg/L additions of caffeic and caftaric acid. This is the first time the influence of hydroxycinnamic acids on furan-derived compounds has been reported during short-term aging of base wine at cellar temperature.

Evolution of the Crown Procyanidins’ Tetramer during Winemaking and Aging of Red Wine

Condensed tannins play a major role in the quality of red wine. After grape extraction, they quickly evolve thanks to different oxidation mechanisms. Recently, NMR identified a new sub class of condensed tannins, named crown procyanidins, in red wine. The crown procyanidins’ tetramer exhibits a macrocyclic structure composed of four (-)-epicatechin with an unusual cavity in the center of the molecule. These new tannins exposed a higher polarity than the linear tannins. In this work, the evolution kinetics of these crown procyanidins during the winemaking process and after aging of red wine in bottles were studied. Samples’ quantification was analyzed by UPLC-UV-Q-TOF. The concentration of cyclic and non-cyclic procyanidins was compared. During the winemaking process, crown procyanidins are mainly extracted at the beginning of the alcoholic fermentation and they remain stable until the end of the winemaking process. The high polarity and solubility of this new molecule in water was confirmed. During the aging of red wine in bottles, crown procyanidins’ concentrations are stable, whereas the non-cyclic tannins decrease dramatically. Finally, a strong oxygenation experiment confirmed the crown procyanidins’ resistance to oxidation and unique skills.