Wine Styles Research Articles

Overcoming the reproduction of the value(s) system in wine: insights from Southern Arizona

ABSTRACT The underrepresentation of the diversity of wine production around the globe, the standardization of varieties, wine styles, and taste, as well as the imbalance between grapes and place specificity, are global effects of the reproduction of the wine value(s) system. From the context of emerging winegrowing places and through a qualitative analysis of diverse experiences among the first generation of Sonoita-Elgin (Arizona, USA) wine producers, this paper explores the influence of wine value(s) system hierarchy on their practice, knowledge, and development. Despite its low representation and visibility globally, emerging wine places like Arizona are introducing new actors to the global wine scene, questioning the homogenization of varieties and styles, the efficiency of evaluation and classification programs based on geographical indication models, and the challenges of achieving collective representations and global recognition of quality. The particularities of Sonoita-Elgin wine producers facing these challenges reveal alternative perspectives and attributes of the relationship between place of origin, value, and quality. In that regard, this work illustrates how these new interpretations represent the current transformation of the practices, ideas, and meanings in the production and consumption of wine, contributing to critical debates on change.

The changing geography of wine climates and its implications on adaptation in the Italian Alps

AbstractWine production and quality both strongly depend on suitable climatic conditions. Increasing the climate resilience of wine regions is therefore of critical importance but requires instruments to evaluate shifts in climatic conditions and growing suitability. This evaluation is particularly challenging in mountain viticultural areas due to their complex topoclimatic patterns, yet they offer the possibility to analyze climate change impacts and adaptation strategies across various climatic conditions and cultivated varieties. Here, we assessed historical and future bioclimatic conditions and identified effective adaptation strategies toward more sustainable and climate‐resilient wine production in the mountain winegrowing regions within South Tyrol in the Italian Alps. We found significant changes in climatic conditions under future scenarios, such as an increase in the Huglin index (HI) and cool night index (CNI) as well as a decreased dryness index (DI), causing an expansion of suitable areas for viticulture as well as a spread of unprecedented climatic conditions in traditional vineyards. Impacts and suitable adaptation options varied depending on climate type and grape variety, highlighting the need for targeted solutions that balance the need for high‐quality wine production with environmental protection and sustainability. Higher elevated areas over 1000 m a.s.l. will experience an increased suitability raising the need for restrictions regarding the expansion of vineyards to avoid degradation of natural ecosystems and biodiversity declines. In contrast, many traditional winegrowing areas will need to implement a combination of short‐ and long‐term adaptation measures to maintain traditional wine styles. Our findings provide a framework for the assessment of viticultural suitability and the formulation of appropriate adaptation strategies for the sustainable cultivation of wine grapes in a changing climate that applies to a variety of climates and grape varieties.

Studying how dry extract can affect the aroma release and perception in different red wine styles.

Four red wine matrices representing different red wine styles with the same VOCs (volatile organic compounds), were obtained by enriching a bleed wine with increasing amounts of deodorized dry extract obtained from the pressed wine of the same vinification. The release of VOCs was determined by solid phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS), in conditions mimicking those applied during sensory assessments. Results show that even though the perception of the overall odor intensity was not significantly influenced by the matrix, this latter modulated the odor profiles: at rising wine dry extract, fruity, floral odors decreased, while dehydrated fruit, woody-toasty, vegetal-earthy notes increased. These changes cannot be fully explained by the observed significant influence of the matrix on the release of VOCs or by their correlations with the considered matrix components (ethanol, residual sugars, phenolics, pH), but findings suggest that perceptual interactions are involved. This study could be useful in pressing and blending management for wine aroma quality also considering wine compositional trends under the current climate change context. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Correlation of chemical composition and sensory scores in Spanish Monastrell red wines: Insights from a blind wine competition

Red wine is a complex beverage, both chemically and sensorially, making it a very interesting beverage from a sensory perspective. Additionally, wine offers consumers a multitude of choices and brands. Considering this diversity, wine competitions and scoring could provide a way of helping consumers in their choices. In this study, sixty-seven commercial Spanish Monastrell red wines, which participated in an official blind contest, were grouped into different winemaking categories based on aging and wood contact. These wines were chemically analyzed to explore relationships between their allocated groups and their chemical composition. Additionally, the study aimed to find correlations between the total scores given in the contest and the wines' volatile compounds, chromatic parameters, and physicochemical properties. The goal was also to identify the chemical parameters that most strongly correlated with the obtained scores. Considering all 67 wines, the results showed a significant linear regression between the wine scores and their physicochemical and volatile compounds, with a coefficient of determination of 48.4 %. However, when the wines were analyzed considering the different categories, the coefficient of determination for those wines competing in the category of aged wines increased up to 84.8 %. In addition, some wine chromatic characteristics such as color intensity, total phenol index and polymeric anthocyanin seemed to be highly related to the score received for the wines in a contest. Therefore, the results obtained in this work can be useful to define a certain style of wine that most probably could get a higher score in a wine contest.

Adoption and Impact of Fungus-Resistant Grape Varieties within German Viticulture: A Comprehensive Mixed-Methods Study with Producers

The reduction of phytosanitary treatments in viticulture is widely demanded by policymakers and consumers. An important solution is the use of resistant grapes, which can cut plant protection applications by up to 80%. Although this is a significant improvement, viticulture is mainly carried out with traditional grapes. Therefore, the aim of this paper is to identify the factors that encourage the cultivation of fungus-resistant grape varieties (FRGV), as well as the challenges and opportunities in marketing. Our study used an exploratory sequential mixed-methods model design. In the first step, data were collected through 48 in-depth interviews and analyzed. Based on the qualitative results, a survey of 422 producers was conducted. The quantitative research results were segmented by company size and production type to provide a deeper understanding. The main drivers for cultivation are the ecological benefits resulting from the reduction of pesticide use, with organic producers particularly motivated by sustainability goals. Smaller producers are driven by the opportunity to introduce a new wine style, whereas larger producers are more cautious and focus on cost savings. The cultivation of resistant grape varieties is restricted by a large number of varieties, lack of experience, and unfavorable characteristics from initial generations of resistant grapes. A low level of grape variety prominence and customer awareness, as well as unattractive variety names, negatively affect producer acceptance. To facilitate higher market acceptance, it is important to offer attractive grape varieties, directly communicate them to consumers, and provide information about the sustainable effects.

Cultural differences in wine conceptualization among consumers in France, Portugal and South Africa

Consumers’ mental pictures of wine are multifaceted and are shaped by their sensory (taste, smell, visual, sensation) perceptions, in addition to emotional, cultural and extrinsic (brand, price, and awards) influences. This study explores whether consumers from three different wine cultures share mental representations of three wine concepts. Through an online survey, French, Portuguese, and South African wine consumers described their conceptualizations of Wine, Red wine and White wine aroma. Given these nations’ rich winemaking traditions and diverse wine styles, differences in consumer perspectives were likely to emerge. The findings demonstrate that, regardless of cultural background, the broad concept of Wine aligns with the more specific Red and White wine conceptualizations, although the latter concepts diverge from each other. Notably, cultural contexts significantly influence participants’ representations of Red Wine, with particularly marked contrasts between the South African and French respondents. This suggests that like experts, wine consumers have also built representations of wine through semantic memory. This cross-cultural analysis of consumer interpretations of wine concepts holds the potential for refining marketing strategies to overcome cultural barriers in wine purchasing behaviour.

Strain prevalence and killer factor only partially influence the fermentation activity of pairwise Saccharomyces cerevisiae wine strains inoculation.

Commercial Saccharomyces cerevisiae starters are single-strain cultures widely used in winemaking to optimise the fermentation process and improve the organoleptic quality of wine. Unfortunately, the worldwide extensive use of a limited number of industrial strains led to the standardisation of the sensory properties, reducing the identity of wines. Therefore, the use of multi-strain S. cerevisiae starters can be an alternative tool to alter the sensory profile of wines, increasing the diversity of wine styles. However, this strategy may be interesting only if the overall fermentation kinetics is not affected. To date, there is a lack of information regarding the influence of multi-strain starters on the overall fermentation process in wine. In this context, killer toxins, affecting the viability of sensitive strains, can play a significant role. This study aimed to evaluate the effects of pairing eight wine strains of S. cerevisiae (two sensitive, three neutral and three killer) in co-fermentations compared to single-strain fermentations. Results evidenced that, among co-fermentations where the strain prevalence was significant, the killer strains constituted 79% to 100% of the total yeast population when co-inoculated with a sensitive one. However, in most of the cases, co-fermentations kinetics were similar to those of sensitive strains or worse than both strains. Thus, the presence of a killer strain alone is not sufficient to predict the overall fermentation progress, which is an essential information in winemaking. Interestingly, the neutral strain P304.4 was always prevalent, regardless of the second strain and, in most of the co-fermentations, the overall fermentation trend was similar to the P304.4 single-strain fermentation. Regardless of killer activity, our results suggest that the effect of strains on fermentative kinetics is still unpredictable, and further studies are needed to thoroughly explore strain to strain interactions in winemaking.

The Impact of Microbial Activity on the Chemical Composition and Aroma Profile of Traditional Sparkling Wines

Traditional sparkling wines are produced in a two-step sequence of alcoholic fermentations, followed by extended aging which is an influential factor for the final aroma profile. Traditionally, the second fermentation and aging are conducted in bottles over a minimum of 18 months, resulting in an aroma profile which is shaped by oxidative secondary metabolites like aldehydes, acids and fatty acid esters. In this study, a total of 29 traditional commercial sparkling wines from the categories Champagne, Cava, California Champagne, and others (Prosecco and Cremant) were analyzed. The objective was to determine the impact of microbial activity on the stylistic characteristics of traditional sparkling wines and allow winemakers to reproduce the specific fermentation conditions. The results indicate that malolactic fermentation plays an important role in Champagne and some Cavas, but not in the other sparkling wine categories. The metabolic activity of lactic acid bacteria results in an altered acid profile, amino acid utilization, and aroma production. While primary fermentation esters like phenylethyl acetate and isoamyl acetate are significantly reduced in Champagne and Cava, aroma compounds from secondary microbial activity like ethyl lactate and 2-acetyl-1-pyrroline are increased. This underlines the importance of diverse microbial activity of the characteristic style of traditional sparkling wines.

The double-edged effects of visualizing wine style: sweetness scale on wine label

PurposeA visual sweetness scale with an arrow pointing to a specific sweetness level is now required on all labels of AOC Alsace. The sweetness scale makes it easier for consumers to understand what is in the bottle. What is less clear, however, is whether such labeling is always effective. To fill this gap, the current research paper aims to examine the positive and negative effects (double-edged effects) of a visual sweetness scale and identify the boundary condition.Design/methodology/approachTwo studies were conducted using a 2 (cue type: scale vs text) by 2 (consumer type: novices vs experienced wine consumers) between-subjects, quasi-experimental design.FindingsThe double-edged effects are only significant among wine novices. Specifically, though wine novices are more likely to purchase wine with a sweetness scale (vs text) due to perceived diagnosticity (Study 1), they are unwilling to pay more due to low perceived quality (Study 2).Practical implicationsThe study findings provide practical implications for wine producers, marketers and restaurants regarding when and how to use the sweetness scale on wine labels and wine service.Originality/valueTo the best of the authors’ knowledge, this research is the first to reveal the impact of visualizing wine style on wine labels. More importantly, while most previous research demonstrates the positive effects of using visual cues, this research sheds light on its drawbacks and examines the underlying mechanisms.

Development of a Novel Approach for Controlling and Predicting Residual Sugars in Wines

Residual sugars (RS) in wine are the sugars that remain in a wine after fermentation is complete. In some wine styles, such as semi-dry wines, the accurate measurement of the RS concentration is critical for both qualitative and legislative reasons. Brix, measured by a simple refractometer, can give a good estimation of the RS concentration in the must, but during fermentation, the presence of alcohol leads to inaccurate sugar measurements. In order to measure the RS accurately, other more precise techniques are used, most of which are expensive or require professional skills. Therefore, novel approaches for rapid, easy, and practical measurements for estimating the sugar content have been suggested over the years. However, most of these methods do not supply an actual measurement of RS but rather give brix values, and those that measure RS involve special equipment, which is less relevant for small wineries. This study suggests a novel model for predicting and controlling the wine’s residual sugar. The data the model uses is the initial brix of the must before fermentation and its density during fermentation. The model was created by measuring actual residual sugars during the fermentation of natural and synthetic musts, with various degrees of initial brix levels, while simultaneously measuring their densities and correlating the two measurements. Linear regression between the residual sugar of the wine and its density was obtained for all treatments and repetitions (i.e., different values of must initial brix) with R2 values above 0.97. Using the model, one can calculate (before commencing the fermentation) the density values at which the fermentation will reach a particular desired residual sugar value for a specific initial brix level; the model is applicable for the fermentation conditions used in this work, i.e., brix levels of 18–27 °Bx, Saccharomyces cerevisiae strains (fx-33 and fx-10) in common conditions of fermentation regarding temperature and aeration.

Comprehensive two-dimensional gas chromatography-high resolution mass spectrometry for the detailed qualitative analysis of old vine Chenin blanc wine volatiles and comparison with young vine Chenin blanc wines

Old vine Chenin blanc (OVC) wines are produced from grapes harvested from vines older than 35 years, verified as Certified Heritage Vineyards in South Africa. This emerging premium wine style is of interest due to the purported unique sensory properties of these wines, including their complex aroma. There is however limited information available on the volatile constituents of these wines, which are primarily responsible for perceived aroma. The wine volatilome is exceedingly complex, and requires advanced analytical approaches to investigate. The present contribution reports the evaluation of comprehensive two-dimensional gas chromatography (GC × GC) as a powerful separation technique to gain qualitative insight into the volatile composition of OVC wines. Extraction of volatile compounds was performed using headspace solid-phase microextraction (HS-SPME), while the GC × GC separation was hyphenated to high speed high resolution time-of-flight MS (HR-TOF-MS) for compound identification. A representative set of eight Chenin blanc wines produced from young vines (YVC) was also analysed to investigate the potential use of GC × GCHR-MS data to differentiate these two wine styles based on differences in their volatile composition. The results confirm the utility of GC × GCHR-MS for the detailed qualitative analysis of wine volatiles, with a total of 277 compounds identified in the studied wines. 53 compounds were uniquely identified in the OVC samples, and 52 in YVC wines. Successful differentiation of the young- and old-vine wines was achieved based on tile-based Fisher (F) ratios and principal component analysis (PCA), although this differentiation could not be clearly linked to winemaking practices (wood maturation) or viticultural origin.

INNOVATIVE DESIGN TECHNOLOGIES OF A MODERN MINIWINERY TAKING INTO AC-COUNT THE TERROIR FOR PINOT NOIR

The article presents a brief overview of scientific works that were aimed at studying the influence of terroir, harvest and technology on the quality and specificity of wine. Modern scientific methods for identifying wines from different regions are considered. Modern studies by Chinese oenologists have shown that a number of trace elements in wine (Cu, Zn and Mn) can be an indicator of the region of origin of the wine. Scientists from Australia, New Zealand, the USA, France and Portugal have also obtained interesting results in the identification of wines of different vintages and terroirs. Scientists have shown that the originality of table wines of specific regions and subregions can be determined on the basis of modern highly sensitive methods of analysis (spectroscopic methods for studying compounds using the phenomenon of nuclear magnetic resonance; combined methods with the joint use of NMR and the study of the target differential sensor matrix; fluorescent methods for determining the content of amino acids and amines, methods of cluster analysis, etc.). When determining the terroir for red wines, many researchers in different regions of our planet paid special attention to the Pinot Noir variety. This is due to the fact that for this particular variety, terroir plays a huge role in shaping the style of the future wine. At the Vinoman winery, together with the Odessa National Technological University, a comparative analysis of red table wines Pinot Noir from three terroirs of the southern part of the Odessa region was carried out. In addition, as part of the master's qualification work, an innovative project for the reconstruction of an existing enterprise was proposed, which involves the implementation of the gravitational principle of winemaking. The project takes into account the features of the area, climatic conditions and the range of products. Particular attention was paid to the implementation of all of the above aspects in the technology for the production of high-quality red table wines Pinot Noir. As a result of the work carried out, physical and chemical indicators were studied and a sensory analysis of the wines of the Bolgrad, Izmail and Reni terroirs was carried out. Based on the data obtained, preliminary conclusions were made about the prospects for the production of red table wines Pinot Noir at the Vinoman enterprise from certain terroirs in the south of the Odessa region.

Fine wine recognition and appreciation: It is time to change the paradigm of wine tasting

Wine quality maybe understood under two perspectives: (a) commercial quality, intended to satisfy overall consumers, and (b) fine wine quality, aimed at achieving a product with aesthetic value. The current food sensory techniques (e.g. Descriptive Analysis) have been successfully applied to develop wines accepted worldwide and characterized by pleasant sweetish flavours and smooth mouthfeel. On the contrary, these techniques are not suited to characterize fine wines given their dependence on sensory properties with aesthetic value. The conventional tasting approaches follow the sequence of vision, smell (orthonasal), taste and mouthfeel, ending by an overall evaluation. The sensory descriptors tend to be analytic (e.g. different aromas and tastes) or synthetic (e.g. body, structure) and the quality judgement is left for the final step. Some synthetic attributes may have an aesthetic significance (e.g. complexity, harmony, depth) and are more valued when the analytic or synthetic descriptors are highly praised (e.g. oakiness, silkiness, body, minerality). Consequently, these highly praised attributes are regarded as surrogates of fine wine quality. However, commercial wines are frequently judged of higher quality than fine wines irrespective of the taster expertise. We argue that the conventional sensory analysis sequence makes the overall evaluation secondary in relation to the previous analytical steps blurring the assessment of wine’s aesthetic properties. Probably due to top-down processing, the initial evaluation of colour or flavours governs the final overall quality evaluation that may be inconsistently rated. Then, to promote the recognition of fine wines, tasting should begin by first acknowledging the aesthetic properties and only proceed to the analytical steps if necessary. A tasting method is proposed to consumer educational programs where emotional responses are used to explain the differences between commercial and fine wine styles. Furthermore, cultural aspects should be included to appreciate the wholeness of wine. Hopefully, this holistic perspective would turn wine appreciation more approachable and facilitate the recognition of fine wines among consumers, increasing their appreciation and enjoyment.

The effect of commercial β-glucosidase and its immobilization on quality of red wine production

To find a feasible strategy for commercial β-glucosidase to enhance red wine quality, immobilized enzyme technology were considered. The preferred epoxy resin using the covalent binding method was ES-103B, and its optimal immobilization conditions were pH 4.9, 25 h immobilization time and 3 mg/g enzyme concentration. Meanwhile, this immobilized β-glucosidase still contained weak esterase activity just like commercial β-glucosidase. Free commercial β-glucosidase had different effects on the fermentation of 11 clones from three grape varieties (Syrah, Merlot and Cabernet Sauvignon) to produce wine. For example, the free enzyme increased the concentrations of β-damascenone, 1-hexanol, phenylethyl alcohol, and three ethyl esters (ethyl hexanoate, ethyl octanoate and ethyl decanoate) in a Cabernet Sauvignon (CS169) wine, but total anthocyanins level was reduced, affecting the color depth (a* value). Notably, during the alcoholic fermentation stage of CS169, immobilized β-glucosidase did not significantly decrease polyphenolic levels and color depth (a* value). What's more, using immobilized β-glucosidase under this treatment condition resulted in the highest levels of higher alcohols, ethyl esters, and acetate. Moreover, β-damascenone content increased by more than 25.35%, as well as phenethyl alcohol and benzaldehyde of benzenic compounds significantly increased by over 72.23% and two-fold, respectively. As a result, CS169 wine possessed more complex aroma and highest sensory score. Therefore, enologists can use immobilized β-glucosidase to develop various strategies that enhance wine quality and produce different wine styles.

Influence of an indigenous yeast, CECA, from the Ningxia wine region of China, on the yeast community dynamics and aroma of Cabernet Sauvignon wines

Commercial yeasts are normally used in the wine industry to achieve stable and enhanced wine flavors and aromas, but they can lead to a loss of diversity and a peculiar regional wine style. An indigenous commercial wine yeast, CECA, has been isolated from a well-known wine-producing region, Ningxia, China. As CECA is a young commercial yeast, further research into its characteristics is required. In this study, the performance of CECA in Cabernet Sauvignon wine fermentation, three different fermentation treatments, spontaneous without inoculation, inoculated with CECA, and inoculated with CECA after treatment of the grape must with dimethyl dicarbonate, were performed. During fermentation, six species of yeast identified through a culture-dependent method were also identified with a culture-independent method, although the relative abundance differed between the methods. The floral and fruity were confirmed as characteristics of CECA-inoculated wines using headspace solid-phase microextraction-gas chromatography-mass spectrometry and sensory evaluation. This study enables winemakers to better understand an indigenous commercial yeast, make a peculiar aroma for Ningxia wines and promote the reputation of Ningxia region.

Plasticity of red wine sensory profiles: improved understanding through grape berry sugar loading profiles

Reproducible aromatic red wine styles can be predicted based upon the measurement of grape berry sugar accumulation (corresponding to the quantity of sugar that accumulates per berry; mg/berry/day) and berry fresh mass. Distinct maturity stages, “Fresh Fruit” reminiscent of fresh/red fruits notes and “Mature Fruit” associated with dark fruit and plum characters could be correlated to berry sugar accumulation (mg/berry) and berry fresh mass evolution without any direct relationship with berry sugar concentration. After berry sugar accumulation plateaued, wine aromatic and phenolic maturity were uncoupled from technological maturity.

Introduced resistant grape variety Frontenac Blanc

Th e paper presents a variety trial and technological evaluation of the wine material from Frontenac Blanc grape, isolated as a color mutation in Canada plantations of the Frontenac Gris variety in 2006. Th e study was carried out in 2020–2022 in compliance with vitiviniculture recognized methodology in soil and climatic conditions of Potapenko All-Russian Research Institute of Viticulture and Winemaking, a branch of Federal Rostov Agrarian Scientifi c Centre, Novocherkassk, Rostov Oblast, Russia. Vineyards are open-earth, rainfed, graft ed, with Kober 5BB rootstock, 3.0×1.5 m planting scheme, shaping: double-shouldered low (40 cm) horizontal cordon, short pruning on knots. Agricultural technology is standard, generally recognized. Frontenac Blanc is found to obtain high winter hardiness, promising for open-earth cultivation. Th e variety has good resistance to infections: to mildew (2.0 score), oidium (2.5 score); grey rot has not been observed. Th erefore, frequent use of pesticides is not required and vineyard maintenance is simplifi ed. Th e high level of sugars (248 g/dm3) and t itratable acids (10.4 g/dm3) in t h e juice ensures a harmonious wine with well-balanced acidity. Due to such characteristics, the variety is considered to be promising for the production of diff erent wine styles, including dry still, semi-dry, as well as sparkling and liqueur wines. Th e wine material from Frontenac Blanc presents a distinguishing character, bright fruit aromas, rich structured fl avor, and lingering fi nish. Th e average tasting score of the wine material comprises 8.6 points (on a 1–10 scale). Th e variety has a high yield (16 tonnes/ha), which does not adversely aff ect the quality of products. Frontenac Blanc is resistant to cold and early ripening period (120 days) and can be eff ectively grown in regions with previously limited production due to extreme climatic conditions. Considering that, an innovative development of the wine industry in areas with cool and uncertain climate possesses a high potential.

Non-Saccharomyces Yeasts from Organic Vineyards as Spontaneous Fermentation Agents.

Currently, non-Saccharomyces yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non-Saccharomyces yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non-Saccharomyces yeasts. Fermentative isolates belonging to the species Hanseniaspora meyeri, Hanseniaspora osmophila, Pichia guilliermondii, Pichia kudriavzevii, Torulaspora delbrueckii, and Wickerhamomyces anomalus were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, W. anomalus stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of W. anomalus presented those activities. T. delbrueckii isolates were highlighted for their significant β-lyase activity. In addition, T. delbrueckii was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.

Dosing oxygen from the early stages of white winemaking: Effect on oxidation–reduction potential, browning stability, volatile composition, and sensory properties

This study investigated the effect of controlled oxygen addition during alcoholic fermentation (4 mg/L, at 2nd, 4th, 6th, 10th, 14th, 16th, 20th day) and aging on lees (2 mg/L, every 15 days for 3 months) in a stainless-steel tank for white wine production from a nearly neutral grape. Under less reductive conditions (Ox), alcoholic fermentation was completed in 27 days, whereas one extra week was required under more reductive conditions (no-Ox). The greatest amount of dissolved oxygen in Ox wine triggered the increase of redox potential (EH) starting from the end of alcoholic fermentation and throughout aging (169 and 150 mV in Ox and no-Ox wine, respectively), also improving the wine resistance to browning. Oxygen addition from the early stages of winemaking significantly modulated volatile composition and sensory attributes, which may contribute to the diversification of wine style.

The Effect of Yeast Inoculation Methods on the Metabolite Composition of Sauvignon Blanc Wines

Evidence from the literature suggests that different inoculation strategies using either active dry yeast (ADY) or freshly prepared yeast cultures affect wine yeast performance, thus altering biomass and many primary and secondary metabolites produced during fermentation. Here, we investigated how different inoculation methods changed the fermentation behaviour and metabolism of a commercial wine yeast. Using a commercial Sauvignon blanc (SB) grape juice, fermentation was carried out with two different inoculum preparation protocols using Saccharomyces cerevisiae X5: rehydration of commercial ADY and preparation of pre-inoculum in a rich laboratory medium. We also determined the effect of different numbers of yeast cells inoculation (varying from 1 × 106 to 1 × 1012) and successive inoculation on fermentation and end-product formation. The yeast inoculation method and number of cells significantly affected the fermentation time. Principal component analysis (PCA) using 60 wine metabolites showed a separation pattern between wines produced from the two inoculation methods. Inoculation methods influenced the production of amino acids and different aroma compounds, including ethyl and acetate esters. Varietal thiols, 3-mercaptohexanol (3MH), and 4-methyl-4-mercaptopentan-2-one (4MMP) in the wines were affected by the inoculation methods and numbers of inoculated cells, while little impact was observed on 3-mercaptohexyl acetate (3MHA) production. Pathway analysis using these quantified metabolites allowed us to identify the most significant pathways, most of which were related to central carbon metabolism, particularly metabolic pathways involving nitrogen and sulphur metabolism. Altogether, these results suggest that inoculation method and number of inoculated cells should be considered in the production of different wine styles.