Sherry Wines Research Articles

Impact of climate change on sustainable production of sherry wine in nearly-zero energy buildings

Wine is the main economic resource in the ‘Area of Jerez’, located in the south of Spain. It is one of the most important wine tourism destinations in the world. However, its sustainable production process, so strongly influenced by climatic conditions, can be clearly affected by the phenomenon of global warming. The ageing process of “Sherry wine” takes place in buildings known as ‘Cathedral warehouses’, an example of Nearly-Zero Energy Buildings (NZEBs). For centuries, they have been used to provide specific ecological conditions for biological ageing without any type of mechanical heating/cooling system. The purpose of this paper is to assess the impact of climate change on this production model. For this, the annual thermal behavior of a representative winery was monitored during several years. The first energy simulation model of this type of buildings was developed and validated (daily R2 = 99%; hourly R2 = 97%). Finally, the model was simulated by modifying the outdoor climatic conditions (9 years training data sets) for a climate change scenario, applying the ‘morphing’ method for the transformation of the weather data. The results show that, by the middle of this century, the average outdoor temperature will increase by 2.3 °C (in summer up to 3.6 °C). As a consequence, the temperature in the ageing zone would exceed the comfort limit for 19% of the year, (up to 34% in hot years). For 2080, the prediction is even worse (average value of 27%). As a result, the microorganisms responsible for this unique process could not maintain their activity. This fact will force the sector to face a harsh reconversion through the adoption of new mechanisms and strategies, which endangers the economic sustainability of an entire region dedicated to this practice. Beyond the specific case, the work highlights the need to evaluate the future behavior of NZEBs through simulation.

Hygrothermal conditions for the biological aging of sherry wine

The present work analyzed the hygrothermal environment of several prestigious warehouses where sherry wines of “Fino” and “Manzanilla” type are made. Through descriptive statistics, frequency histograms and psychrometric diagrams of temperature and relative humidity variations have been obtained. In addition, other factors such as the stability and uniformity of the interior environment have been quantified. The results showed significant temperature variations throughout the year (limit values of 5 °C and 31 °C), with a more stable relative humidity (between 60% and 90% for most of the year). Indoor conditions varied much more rapidly than in wineries for the aging of red wine, as a result of constant ventilation. Therefore, the annual average stability was 2.0 ± 0.8 °C per day and 0.14 ± 0.12 °C per hour. Vertical uniformity decreased in spring and summer, with stratification values close to 0.5 °C/m and 3% r.h./m. The monitored indoor environment is outside the comfort ranges described in the literature for extended periods of time (in the most extreme case, 96% of the time outside the recommended interval). For that reason, a reference psychrometric comfort diagram was proposed. Industrial relevanceFor the first time, the hygrothermal behavior of several wineries producing high quality wines (very high scores in the oenological guides) was extensively analyzed. The results of the study, which include monthly comfort intervals, should be a very useful tool for the sherry wine industry, in order to control and ensure optimal development of the flor yeast film. It should also be taken into account for the correct design of new wineries or the rehabilitation of abandoned warehouses.

Non-Saccharomyces Are Also Forming the Veil of Flor in Sherry Wines

Biological ageing is an essential process for obtaining some distinctive Sherry wines, such as Fino and Manzanilla. It occurs after the fermentation of the grape must due to the appearance of a biofilm on the surface of the wine called “veil of flor”. Yeasts belonging to the Saccharomyces cerevisiae species mainly comprise such biofilm. Although other species have also been found, these have been traditionally considered spoilage. Indeed, it has even been hypothesised that they may not be able to form biofilm on their own under such conditions. In the present work, four different non-Saccharomyces yeasts isolated from barrels in the Jerez area under biological ageing have been characterised through their physiological abilities, including extracellular enzymatic and biofilm-forming capabilities. Results showed not only a surprising ethanol tolerance, above 15.5% in all cases, but also a significant degree of extracellular enzyme production, highlighting the urease and proteolytic activities found in Pichia manshurica, as well as lipolytic activity in Pichia kudriavzevii, Pichia membranifaciens and Wicherhamomyces anomalus. As a conclusion, these non-Saccharomyces could be very interesting in the oenological field, beyond improving the organoleptic characteristics as well as technological features in these wines.

DESIGN OF A SMART PACKAGING FOR SHERRY WINES THROUGH HOLONIC ENGINEERING

The purpose of this study is the introduction of the Holonic framework for the conceptual design of an "intelligent packaging" in the Sherry Wine´s Industry. This purpose is based on the search for an effective design, that is, a design that produces the desired effect on the user, thus fulfilling their expectations and leaving aside the existing problems in the traditional wine packaging. Due to the lack of specific methodologies, the holonic model has been chosen as an integrating framework for the design and development of conventional products. In addition, this model allows to support the combined use of other classical methodologies such as: AHP, QFD, FAST, TRIZ among other, allowing to use in the model, the advantages provided by each of them separately. The result is the methodological application to the design of an intelligent package that achieves the desired goals while improving the consumer experience. The proposed packaging design allows its direct reuse, being advantageous for obtaining certifications and audit approval. In addition, the use of intelligent technologies allows effective control and correct use of the product. Keywords: Sherry wines; holonic engineering; bottle; smart packaging; sustainable design; industrial design.

Sherry Wines: Worldwide Production, Chemical Composition and Screening Conception for Flor Yeasts

The manufacturing of sherry wines is a unique, carefully regulated process, from harvesting to quality control of the finished product, involving dynamic biological aging in a “criadera-solera” system or some other techniques. Specialized “flor” strains of the yeast Saccharomyces cerevisiae play the central role in the sherry manufacturing process. As a result, sherry wines have a characteristic and unique chemical composition that determines their organoleptic properties (such as color, odor, and taste) and distinguishes them from all other types of wine. The use of modern methods of genetics and biotechnology contributes to a deep understanding of the microbiology of sherry production and allows us to define a new methodology for breeding valuable flor strains. This review discusses the main sherry-producing regions and the chemical composition of sherry wines, as well as genetic, oenological, and other selective markers for flor strains that can be used for screening novel candidates that are promising for sherry production among environmental isolates.

Valorization of Traditional Alcoholic Beverages: The Study of the Sicilian Amarena Wine during Bottle Aging

Traditional alcoholic beverages have always been part of the Mediterranean culture and, lately, they have been re-evaluated to valorize both the territory and local customs. In this study, the Amarena wine, a fortified wine included in the national list of the traditional agri-food products, was characterized during bottle aging for oenological parameters, chromaticity, volatiles, and inorganic elements. Then, experimental data were visually interpreted by a principal component analysis (PCA). PCA revealed that most of oenological parameters (i.e., alcoholic grade, total dry extract, sugars, organic acids, and phenolic compounds) had a scarce discriminating power. Additionally, ethyl esters were only present in younger products, while remaining at quite constant levels. Conversely, certain metals (i.e., Mg, Na, Mn, Zn, and Cu), chromatic properties, and pH differentiated older Amarena bottles from the younger counterpart. Particularly, acetaldehyde and furanic compounds proved to be valid aging markers. A sensorial analysis highlighted that fruity and floral odors and flavors characterized younger beverages, while dried fruity, nutty, and spicy notes were displayed by older products, along with the valuable attribute of “oxidized” typically observed in aged Sherry wines. Overall, this study may encourage the production and commercialization of the Amarena wine, thus preserving the cultural heritage of the Mediterranean area.

Influence of alcoholic strength on the characteristics of Brandy de Jerez aged in Sherry Casks®

Brandy de Jerez is produced by ageing wine distillates in casks that have previously contained Sherry wine. A Criaderas and Solera system is used according to the corresponding Technical File. However, the alcohol content of the distillate that is subjected to ageing is not specified, even if this is a factor that affects both brandy quality and production costs. This paper studies the influence that alcohol content has on the physicochemical and sensory characteristics of aged Brandy de Jerez. Six Criaderas and Solera systems have been characterised with alcoholic strengths between 65% and 80% ABV. The brandies with 65% ABV showed a higher concentration of the polyphenolic compounds extracted from the wood and from the wine used to season the casks, and also a higher colour intensity. In addition, these brandies were preferred by the tasters and were granted better scores for the descriptors that characterize Brandy de Jerez.

Revealing the Yeast Diversity of the Flor Biofilm Microbiota in Sherry Wines Through Internal Transcribed Spacer-Metabarcoding and Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry.

Flor yeast velum is a biofilm formed by certain yeast strains that distinguishes biologically aged wines such as Sherry wine from southern Spain from others. Although Saccharomyces cerevisiae is the most common species, 5.8 S-internal transcribed spacer (ITS) restriction fragment length polymorphism analyses have revealed the existence of non-Saccharomyces species. In order to uncover the flor microbiota diversity at a species level, we used ITS (internal transcribed spacer 1)-metabarcoding and matrix-assisted laser desorption/Ionization time of flight mass spectrometry techniques. Further, to enhance identification effectiveness, we performed an additional incubation stage in 1:1 wine:yeast extract peptone dextrose (YPD) before identification. Six species were identified: S. cerevisiae, Pichia manshurica, Pichia membranifaciens, Wickerhamomyces anomalus, Candida guillermondii, and Trichosporon asahii, two of which were discovered for the first time (C. guillermondii and Trichosporon ashaii) in Sherry wines. We analyzed wines where non-Saccharomyces yeasts were present or absent to see any potential link between the microbiota and the chemical profile. Only 2 significant volatile chemicals (out of 13 quantified), ethanol and ethyl lactate, and 2 enological parameters (out of 6 quantified), such as pH and titratable acidity, were found to differ in long-aged wines. Although results show a low impact where the non-Saccharomyces yeasts are present, these yeasts isolated from harsh environments (high ethanol and low nutrient availability) could have a potential industrial interest in fields such as food microbiology and biofuel production.

Analytical and Chemometric Characterization of Fino and Amontillado Sherries during Aging in Criaderas y Solera System.

Fino and Amontillado are Sherry wines, produced in Marco de Jerez area (southern Spain), and aged in Criaderas y Solera system. Fino Sherry wine follows a biological aging process, under a veil of flor yeasts, while Amontillado Sherry wine shares the same biological aging firstly, followed by oxidative aging, which gives them special features. Organic acids, esters, higher alcohols, phenolic compounds and total dry extract of Sherries evolve during aging due to evaporation processes, physical-chemical reactions, wood contributions and microbiological activity. During aging, Sherry wines improve their organoleptic profile, as could be proved in the tasting sessions. Hierarchical Cluster Analysis and Factor Analysis with factor extraction using Principal Components of Sherry wines studied were carried out and natural groupings of the wines according to the type of aging and their age were observed. A strong correlation between the parameters analyzed and the aging of each wine has been seen in the Multiple Linear Regression studies, establishing two different models, one for each type of Sherry wine, that, with only four of all the variables studied estimated the wine age with more than 99% of confidence. This constitutes a useful tool to control the age of these Sherry wines in the winery.

Industrial Buildings with Zero Energy Consumption: Cathedral Warehouse for Sherry Wines

The industrial sector needs solutions and strategies that allow buildings to reduce their energy consumption and develop their daily business activities. This paper discusses the long-term monitoring measures of indoor thermal conditions in a warehouse with zero energy consumption. The objective is to promote the use of passive design strategies within the industrial sector by analyzing an example of the feasibility of achieving controlled environmental conditions with zero energy consumption. In total, more than a million data points were processed and analyzed in different periods of the year. Experimental measurements showed strong gradients in the vertical distribution of temperature, this being a key aspect of the general behavior of the indoor environment of the warehouse. A standard comparison variable was developed to quantify the monthly and daily evolution of vertical stratification of the air to explain in detail the thermal behavior of the warehouse throughout the year. The results showed the efficacy of the design of these constructions to mitigate the high temperatures typical in a Mediterranean-Oceanic climate. This example of ingenuity in passive design demonstrates how, by combining the right strategies, the desired conditions can be obtained without any energy consumption.

Sherry wine industry by-product as potential biosorbent for the removal of Cr(VI) from aqueous medium

A low-cost biosorbent obtained from the Palomino Fino grape seed, a Sherry wine industry by-product, has been proposed as a way of valorising this material. The biomass was characterised obtaining values of 0.68 ± 0.05 g mL−1 for bulk density, 1.02 ± 0.09 g mL−1 for apparent density and 33.3% for porosity. The pHpzc was 5.2 and the surface negative charge value was 2.4 ± 0.2 mmol g−1. The analysis of surface morphology showed differences due to the sorption. The results showed a promising potential for chromium(VI) removal from aqueous solutions. The studies were carried out in batch scale and a 23 factorial design was applied for the optimisation of the process. A percentage of 91.7 ± 0.6% was achieved for the biosorption of Cr(VI) under optimal conditions using pH 5.5, 15 g/L of biosorbent and 8 h of contact time. The biosorption capacity showed a remarkable linearity from 0 to 2 mmol L−1 Cr(VI) and a precision of 0.64% for the removal of 1 mmol L−1 of metal. Langmuir, Freundlich and Temkin isotherm equations and the parameters of six kinetic models were used in the equilibrium modelling and identifying the mechanism of the biosorption. The combination of physical and chemical sorption mechanisms was proposed for the chromium removal with a high maximum sorption capacity (qmax = 208.3 mg g−1). Thermodynamic parameters indicated the spontaneous and endothermic nature of the chromium removal. The successful biosorption was based on the special grape seed components with a relevant content in antioxidant and lignocellulosic compounds.

A Methodology Based on FT-IR Data Combined with Random Forest Model to Generate Spectralprints for the Characterization of High-Quality Vinegars.

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint (“spectralprint”) of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.

Characterization of the Key Aroma Compounds in a Commercial Fino and a Commercial Pedro Ximénez Sherry Wine by Application of the Sensomics Approach.

Following the sensomics approach, the key aroma compounds of a commercial Fino and Pedro Ximénez sherry were identified, quantitated, and validated through recombination experiments. In Fino sherry, 31 compounds were determined in concentrations above their odor detection thresholds, with the fruity/green smelling 1,1-diethoxyethane displaying the highest odor activity value ((OAV); the ratio of the concentration to the odor threshold) of 8970, followed by ethyl (2S,3S)-hydroxy-3-methylpentanoate (853) and 2- and 3-methylbutanal (448). In the Pedro Ximénez sherry, 23 compounds were present in concentrations exceeding their odor thresholds, and the malty smelling 2- and 3-methylbutanal were found with the highest OAV (1006), followed by 1,1-diethoxyethane (808) and methylpropanal (561). The results were compared to those characterized previously by us in an Amontillado sherry revealing that in all three sherry wines, 1,1-diethoxyethane, 2- and 3-methylbutanal, methylpropanal, ethanol, ethyl (2S,3S)-2-hydroxy-3-methylpentanoate, acetaldehyde, and 3-(methylthio)propanal, as well as the fruity-smelling ethyl 2-methylbutanoate, ethyl hexanoate, ethyl octanoate, and ethyl 3-methylbutanoate ranked among the 15 odorants with the highest OAVs. But, although most odorants were identical in the three sherries, their amounts differed significantly. The results are discussed considering the different winemaking processes and the different aroma profiles.

Comparative Evaluation of Brandy de Jerez Aged in American Oak Barrels with Different Times of Use.

Brandy de Jerez is a European Geographical Indication for grape-derived spirits aged in oak casks that have previously contained any kind of Sherry wine and, therefore, are known as Sherry Casks®. Wood compounds have a substantial influence in the quality of the brandies that are aged in the barrels. In the cellar, the barrels that have been used for many years to keep Sherry wine or other wine spirits are often used for this purpose. When wooden barrels are used for the first time, they release a large amount of compounds into the liquid contained in them. Such amount decreases over time but casks life cycle has remained unexplored until now. The present work has the aim to study the brandies obtained from the same wine spirit after two years ageing in three differently oak casks: namely new, 7 years of use (4 years containing Oloroso wine and 3 years containing wine spirits) and 32 years of use (8 years containing Oloroso wine and 24 years containing wine spirits). According to the results from our experiments, even after 32 years of use, the wood barrels still contribute to modify the organoleptic characteristics of brandy. Moreover, the brandies aged in used barrels were judged more balanced than those aged in new barrels.

HPLC-DAD-MS and Antioxidant Profile of Fractions from Amontillado Sherry Wine Obtained Using High-Speed Counter-Current Chromatography.

In the present work, the polyphenolic profile of a complex matrix such as Amontillado sherry has been processed by means of high-speed counter-current chromatography (HSCCC) and characterized by HPLC-DAD-MS. An Amberlite XAD-7 column was used to obtain the wine extract, and three different biphasic solvent systems were applied for HSCCC separation: MTBE (methyl tert-butyl ether)/n-butanol/acetonitrile/water (1.1/3/1.1/5+0.1% trifluoroacetic acid), MTBE/n-butanol/acetonitrile/water (2/2/1/5), and hexane/ethyl acetate/ethanol/water (1/5/1/5). As a result, 42 phenolic compounds and furanic derivatives have been identified by means of HPLC-DAD-MS, with 11 of them being identified for the first time in Sherry wines: 3-feruloylquinic acid, isovanillin, ethyl vanillate, furoic acid, dihydro-p-coumaric acid, 6-O-feruloylglucose, ethyl gallate, hydroxytyrosol, methyl protocatechuate, homoveratric acid and veratraldehyde. In addition, the antioxidant capacity (ABTS) of the obtained fractions was determined, revealing higher values in those fractions in which compounds such as gallic acid, protocatechuic acid, protocatechualdehyde, trans-caftaric acid, syringic acid, isovanillin or tyrosol, among others, were present. This is the first time that HSCCC has been used to characterize the phenolic composition of Sherry wines.

Chemical content and sensory changes of Oloroso Sherry wine when aged with four different wood types

Oloroso Sherry Wine is a fortified Sherry wine obtained by oxidation and ageing in American oak barrels of 500 L–600 L. In this work, the study of the suitability of other types of woods for the ageing of these wines was carried out. To compare the characteristics of the alternative woods, an oloroso wine was aged in four groups of 16 L barrels made of French oak, Spanish oak, chestnut, as well as American oak as control, with intense and medium toasting. Phenolic and furanic compounds, organic acids, volatile compounds, color characteristics, total polyphenol index and sensory analysis of wines aged for two months were analyzed. The results confirmed that the aged samples could be differentiated on the basis of their chemical composition, and that the use of alternative woods to age oloroso Sherry wines, and the level of wood toasting, had the potential to provide products with specific differences to the traditional aged in American oak. Furthermore, the organoleptic characteristics of these alternative wines were valued above a standard Sherry wine.

A Differential Proteomic Approach to Characterize the Cell Wall Adaptive Response to CO2 Overpressure during Sparkling Wine-Making Process.

In this study, a first proteomic approach was carried out to characterize the adaptive response of cell wall-related proteins to endogenous CO2 overpressure, which is typical of second fermentation conditions, in two wine Saccharomyces cerevisiae strains (P29, a conventional second fermentation strain, and G1, a flor yeast strain implicated in sherry wine making). The results showed a high number of cell wall proteins in flor yeast G1 under pressure, highlighting content at the first month of aging. The cell wall proteomic response to pressure in flor yeast G1 was characterized by an increase in both the number and content of cell wall proteins involved in glucan remodeling and mannoproteins. On the other hand, cell wall proteins responsible for glucan assembly, cell adhesion, and lipid metabolism stood out in P29. Over-represented proteins under pressure were involved in cell wall integrity (Ecm33p and Pst1p), protein folding (Ssa1p and Ssa2p), and glucan remodeling (Exg2p and Scw4p). Flocculation-related proteins were not identified under pressure conditions. The use of flor yeasts for sparkling wine elaboration and improvement is proposed. Further research based on the genetic engineering of wine yeast using those genes from protein biomarkers under pressure alongside the second fermentation in bottle is required to achieve improvements.

Rethinking about flor yeast diversity and its dynamic in the “criaderas and soleras” biological aging system

Fino wine is one of the most important Sherry wines and it is obtained through a complex and dynamic biological aging system. In this study, wine and veil of flor samples from fifty-two barrels with different aging levels and distributed in three different wineries from the Jerez-Xèrés-Sherry winemaking area have been analyzed during two years. Some of the wine compounds most deeply involved in flor yeast metabolism were analyzed to take into account the blending effect of this system. On the other hand, veil of flor was analyzed by molecular methods, finding five different species: S. cerevisiae, W. anomalus, P. membranaefaciens, P. kudriavzevii and P. manshurica, being the first time that the three last species have been reported in this biological aging system. Since S. cerevisiae was the vast majority of the isolates, its intraspecies variability was also analyzed by the simultaneous amplification of three microsatellite loci, obtaining nine different S. cerevisiae genotypes, also differentiated according to their physiological properties. Biodiversity analysis showed there were significant differences between the three wineries in the three aging scales, although the overall diversity was relatively low. Moreover, variations in the relative frequency of the different S. cerevisiae genotypes were found to be seasonal-dependent.

Autophagic Proteome in Two Saccharomyces cerevisiae Strains During Second Fermentation for Sparkling Wine Elaboration.

A correlation between autophagy and autolysis has been proposed in order to accelerate the acquisition of wine organoleptic properties during sparkling wine elaboration. In this context, a proteomic analysis was carried out in two industrial Saccharomyces cerevisiae strains (P29, conventional sparkling wine strain and G1, implicated in sherry wine elaboration) with the aim of studying the autophagy-related proteome and comparing the effect of CO2 overpressure during sparkling wine elaboration. In general, a detrimental effect of pressure and second fermentation development on autophagy-related proteome was observed in both strains, although it was more pronounced in flor yeast strain G1. Proteins mainly involved in autophagy regulation and autophagosome formation in flor yeast G1, and those required for vesicle nucleation and expansion in P29 strain, highlighted in sealed bottle. Proteins Sec2 and Sec18 were detected 3-fold under pressure conditions in P29 and G1 strains, respectively. Moreover, ‘fingerprinting’ obtained from multivariate data analysis established differences in autophagy-related proteome between strains and conditions. Further research is needed to achieve more solid conclusions and design strategies to promote autophagy for an accelerated autolysis, thus reducing cost and time production, as well as acquisition of good organoleptic properties.

Transcriptome Profile of Yeast Strain Used for Biological Wine Aging Revealed Dynamic Changes of Gene Expression in Course of Flor Development.

Flor strains of Saccharomyces cerevisiae are principal microbial agents responsible for biological wine aging used for production of sherry-like wines. The flor yeast velum formed on the surface of fortified fermented must is a major adaptive and technological characteristic of flor yeasts that helps them to withstanding stressful winemaking conditions and ensures specific biochemical and sensory oxidative alterations typical for sherry wines. We have applied RNAseq technology for transcriptome analysis of an industrial flor yeast strain at different steps of velum development over 71 days under experimental winemaking conditions. Velum growth and maturation was accompanied by accumulation of aldehydes and acetales. We have identified 1490 differentially expressed genes including 816 genes upregulated and 674 downregulated more than 2-fold at mature biofilm stage as compared to the early biofilm. Distinct expression patterns of genes involved in carbon and nitrogen metabolism, respiration, cell cycle, DNA repair, cell adhesion, response to various stresses were observed. Many genes involved in response to different stresses, oxidative carbon metabolism, high affinity transport of sugars, glycerol utilization, sulfur metabolism, protein quality control and recycling, cell wall biogenesis, apoptosis were induced at the mature biofilm stage. Strong upregulation was observed for FLO11 flocculin while expression of other flocculins remained unaltered or moderately downregulated. Downregulated genes included those for proteins involved in glycolysis, transportation of ions, metals, aminoacids, sugars, indicating repression of some major transport and metabolic process at the mature biofilm stage. Presented results are important for in-depth understanding of cell response elicited by velum formation and sherry wine manufacturing conditions, and for the comprehension of relevant regulatory mechanisms. Such knowledge may help to better understand the molecular mechanisms that flor yeasts use to adapt to winemaking environments, establish the functions of previously uncharacterized genes, improve the technology of sherry- wine production, and find target genes for strain improvement.