Riesling Wines Research Articles

Soil types as extrinsic cues differentially shape sensory perception of German Riesling wine

Despite the lack of consensus regarding the effects of different soils on wine flavour, the simplification of terroir to soil type has become increasingly common in wine marketing, particularly for German Riesling. To examine the effects of this strategy on sensory perception, twenty German Rieslings from four commonly marketed soil types (Buntsandstein, Löß, Muschelkalk, and Schiefer) were evaluated for aroma, taste, and mouthfeel attributes (rate-all-that-apply) by a panel of twenty wine experts, first without and then with each wine’s soil type given as an extrinsic informational cue. While ratings from the uninformed tastings suggest baseline differences among Rieslings from the various soils, the provision of soil type cues resulted in more extensive discrimination, particularly in terms of attributes related to minerality (earthy, chalky, marine, flinty, and salty). Soil type-dependent changes in ratings suggest distinct a priori conceptions for each soil shaped the panel’s expectations and differentially altered their perception, though further work is needed to determine whether nonexpert consumers would be similarly biased by these cues. For wine soil typing to be a viable marketing strategy, a well-defined “image” of each soil would need to be communicated to consumers, to ensure their expectations are set to trigger perception of the desired sensory properties.

Verbal descriptions modulate flavour perception and evaluation of wine: An exploratory study using Riesling and Muscat Bailey A wines

Significant efforts have been made in the wine industry to assist customers in making purchase decisions and enhance their drinking experience by providing verbal descriptions of the complex sensory characteristics of wine. However, the influence of such verbal descriptions on wine flavour perception and evaluation has not been examined. To fill this gap, this exploratory study performed an experiment using white Riesling wine from the 2021 German vintage and red Muscat Bailey A (MBA) wine from the 2019 Japanese vintage. Forty-six Japanese individuals (23 social drinkers and 23 wine experts) participated and were presented with two glasses of Riesling wine and two glasses of MBA wine with different verbal descriptions. One glass of Riesling/MBA wine was served with a description including its distinct aroma descriptor (i.e., a ‘petrol’ note for the Riesling wine and a ‘strawberry candy’ note for the MBA wine). For the other glass, the description did not include the descriptor. The participants were asked to taste the wines and rate their palatability, perceived sweetness intensities, acidity, astringency, alcohol sensation, body, and expensiveness on a 7-point scale. The results demonstrated that the social drinkers rated the Riesling wine with the ‘petrol’ descriptor as heavier-bodied and more expensive compared to the same wine without the descriptor. The wine experts were not as influenced as the social drinkers, but the experts rated the Riesling wine with the ‘petrol’ descriptor as less expensive. In the case of MBA wine with the ‘strawberry candy’ descriptor, the social drinkers rated it as more expensive, whereas the wine experts rated it as more palatable than the same wine without the descriptor. The results indicated that verbal descriptions of wine aroma indeed modulated the flavour perception and evaluation of wine, but the modulation effect varied between social drinkers and wine experts.

Comparative assessment of Riesling wine fault development by the electronic tongue and a sensory panel.

Wine faults threaten brand recognition and consumer brand loyalty. The objective of this study was to compare the acuteness of e-tongue and human sensory evaluation of wine fault development in Riesling wine over 42days of storage. Riesling wines uninoculated (control) or inoculated with 104CFU/mL cultures of Wickerhamomyces anomalus, Acetobacter aceti, Lactobacillus brevis, or Pediococcus parvulus were assessed every 7days with the e-tongue and a rate-all-that-apply (RATA) sensory panel. After 7days of storage, the e-tongue detected differences in all four wine spoilage microorganism treatments, compared to control wine, with discrimination indices over 86%. The RATA sensory panel detected significant differences beginning on day 35 of storage, 28days after the e-tongue detected differences. This study showed that the e-tongue was more sensitive than the human panel as a detection tool, without sensory fatigue. PRACTICAL APPLICATION: This research is useful for winemakers seeking additional instrumental methods in the early detection of wine faults. Given the results of this study, the e-tongue can be a useful tool for detecting early chemical changes in white wines that have undergone microbial spoilage, providing winemakers with time to mitigate faults before they surpass sensory thresholds.

Improving the aging aroma profiles of Italian Riesling and Petit Verdot Wines: Impact of spontaneous and inoculated fermentation processes

The study employed gas chromatography-ion mobility spectrometry to differentiate between wines undergoing spontaneous fermentation and inoculated fermentation, with aging periods of 3, 9, and 15 months. The results indicate that throughout the three aging periods, there was a notable increase in the levels of ethyl hexanoate (Monomer, M), 2-methyl butanal, ethyl octanoate (M), ethyl octanoate (Dimer, D), propyl acetate, and 3-methylbutanal in the spontaneous Italian Riesling wine (RS). Furthermore, the compounds isoamyl acetate (M), ethyl formate (D), 4-methyl-2-pentanone (M), and ethyl formate (M) demonstrated the highest concentrations at 15 months in RS, accordingly, these compounds displayed a consistent upward trend throughout the aging period. A total of 14 volatile compounds exhibited an upward trend from 3 to 15 months in the spontaneous fermentation of Petit Verdot Wine (VS). Subsequently, these compounds attained their maximum levels. Spontaneous fermentation effectively enhances the aromatic characteristics of wines, consequently improving their capacity for aging.

1,1,6-Trimethyl-1,2-dihydronaphthalene Content of Riesling Wines in Hungary.

1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is known to give a petrol note when smelling and tasting wine, which is most pronounced in Riesling varieties. Its increasing concentration has been linked to climate change. In the present work, a gas chromatographic method was used to quantify free TDN in "Italian Riesling", "Rhine Riesling", and "Kéknyelű" wines from Hungary. From the vintages 2010 to 2020, 39 bottles of wine from different wine regions were evaluated by instrumental analysis and sensory evaluation. Our aim is to determine the extent to which the Riesling wines in Hungary show a petrol character. The other objective was a comparison of sorts to see if there is a difference in TDN production potential between Italian Riesling and Rhine Riesling. We also aimed to clarify the question whether the Hungarian variety Kéknyelű is also capable of developing a petrol character. The wines we tested were corked and screw-locked. This allowed us to compare the difference in TDN concentration variation over time between the two closure methods.

New Insight on the Formation of 2-Aminoacetophenone in White Wines

This study aimed to improve the understanding of 2-aminoacetophenone (2-AAP) formation in white wines, a compound responsible for atypical ageing (ATA) associated with a rapid loss of white wine fruity aroma and to the development of unpleasant odors. Two surveys performed in 139 white wines from Central Europe investigated the varietal effect on wine tendency to form 2-AAP during ageing. The role of some antioxidants and important transition metal ions present in wine (Fe, Cu and Mn) in the formation of 2-AAP was also investigated. The surveys highlighted that Muscat and Riesling wines showed significantly higher concentrations of 2-AAP than Chardonnay and some other regional varieties found in Central Europe such as Grüner Veltliner, Welschriesling and Zelen. The origin of such varietal effects could not be related to the level of any 2-AAP precursor. On the other hand, some of the important wine matrix effects were highlighted. A certain variability in capacity of different antioxidants to limit 2-AAP formation was observed. Supplementations of commercial tannins in wines tended to be more efficient than glutathione in preserving wines from the formation of 2-AAP. Transition metal ions significantly impacted 2-AAP synthesis through complex interactions. Generally, Fe and Mn tended to promote formation of 2-AAP, while the presence of Cu limited it. The higher concentration of transition metal ions significantly improved the efficiency of antioxidants to reduce 2-AAP formation. Further studies investigating the origin of varietal effects and the complex matrix effects involving metal ions and antioxidants in 2-AAP production are warranted.

Investigation of molecular changes in wine during storage in refrigerated cabinets

Investigation of molecular changes in wine during storage in refrigerated cabinets

Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts.

It is expected that any processing and handling of lees (e.g., drying, storage or removal of residual alcohol using various concentration techniques) will expose the material to oxidation and the consequences of oxidation on the biological activity of the lees and the lees extracts are unknown. The effects of oxidation (using horseradish peroxidase and hydrogen peroxide model system) on phenolic composition and their antioxidant and antimicrobial activities were investigated in (i) a flavonoid model system composed of catechin and grape seed tannin (Cat:GST) extracts at various ratios and (ii) in Pinot noir (PN) and Riesling (RL) wine lees samples. For the flavonoid model, oxidation had a minor or no impact on total phenol content but increased (p < 0.05) total tannin content from approximately 145 to 1200 µg epicatechin equivalent/mL. An opposite observation was found in the PN lees samples where oxidation reduced (p < 0.05) the total phenol content (TPC) by approximately 10 mg GAE/g dry matter (DM) lees. The mean degree of the polymerization (mDP) values of the oxidized flavonoid model samples ranged from 15 to 30. The Cat:GST ratio and interaction of the Cat:GST ratio with oxidation were found significantly to affect the mDP values of the flavonoid model samples (p < 0.05). Oxidation increased the mDP values in all oxidized flavonoid model samples except for Cat:GST 0:100. The mDP values of the PN lees samples ranged from 7 to 11 and remained the same after oxidation. There was no significant reduction in the antioxidant activities (DPPH and ORAC) of the model and wine lees after oxidation except the PN1 lees sample (decreased from 3.5 to 2.8 mg Trolox equivalent/g DM extracts). In addition, no correlation was observed between mDP (approximately 10 to 30) and DPPH (0.09) and ORAC assay (-0.22), which indicates that the higher mDP resulted in a poor ability to scavenge DPPH· and AAPH· free radicals. Antimicrobial activities of the flavonoid model were found to be improved after the oxidation treatment against S. aureus and E. coli with minimum inhibition concentration (MIC) of 1.56 and 0.39 mg/mL. This may indicate that new compounds were formed during the oxidation treatment, and these compounds showed more effective microbicidal activity. LC-MS work is required in the future to identify the compounds that are newly formed during the oxidation of the lees.

Effects of Mixed Fermentation on the Aroma Compounds of ‘Italian Riesling’ Dry White Wine in Eastern Foothill of Helan Mountain

To study the effect of mixed fermentation of non-Saccharomyces strains and Saccharomyces cerevisiae on the aroma quality of ‘Italian Riesling’ wine in the eastern foothill of Helan Mountain and to determine the most optimum process of mixed fermentation, two selected non-Saccharomyces strains, including Hanseniaspora uvarum YUN268 and Pichia fermentans Z9Y-3, were inoculated with Saccharomyces cerevisiae in different proportions (10:1 or 1:1) and different stages (48 h in advance or simultaneously at the beginning) to ferment ‘Italian Riesling’ dry white wine. The oenological parameters and aroma indexes of the wine samples were evaluated. The results showed mixed fermentation can not only reduce the alcohol content of wine 0.24~0.71% vol but also increase the glycerol content to improve the taste of wine. The mixed fermentation effect of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae resulted in improvements, especially the high proportion (10:1) sequential inoculation and simultaneous inoculation of wine samples (WSP10 and WCP10), which not only produced more volatile aroma substances and glycerol content but also increased the total amount of ester substances by 49.4% and 56.5%, respectively, compared with the control. The sensory evaluation scores of WSP10 and WCP10 were significantly higher than the control (89.3 and 88.1 points, respectively). At the same time, it can also enhance the aroma of lemon, cream, almond, and others and increase the aroma complexity of wine. Therefore, these two methods of mixed fermentation inoculation are more suitable for the production of Italian Riesling wine in the eastern foothill of Helan Mountain. In conclusion, the mixed fermentation of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae 10:1 (simultaneous or sequential) inoculation is suitable for the production of Italian Riesling dry white wine in the eastern foothill of Helan Mountain.

Evaluation of plant phenolic extracts as an alternative to sulfur dioxide for the control of Oenococcus oeni and Brettanomyces bruxellensis

In the current work, the potential of plant phenolic extracts to replace the ability of SO2 to inhibit spoilage microorganisms was evaluated. The study included the application of different doses of plant phenolic concentrates to test their antimicrobial activity against O. oeni, and Brettanomyces yeasts. For the evaluation of O. oeni, Chardonnay and Riesling wines were inoculated with the lactic acid bacteria, and antimicrobial agents were added: SO2 or phenolic concentrates. Then within seven weeks and six months, the levels of malic and lactic acids in the control and treated samples were monitored. In the tests to verify the control of Brettanomyces, oak cubes were contaminated with the spoilage yeasts and later treated with water (control) or two aqueous sanitizing solutions (conventional one: water with citric acid and SO2; experimental one: containing phenolic concentrates). Later, the corresponding solutions and water were analyzed for the presence of Brettanomyces yeasts by observation and plate numbering. Results confirm the inhibitory capacity of the phenolic concentrates tested regarding these two microorganisms, showing promising results.

Impacts of photoselective bunch zone shading on the volatile composition and sensory attributes for &lt;i&gt;Vitis vinifera&lt;/i&gt; L. cv. Riesling

Photoselective shading is a process that modulates the radiation intensity in specific regions of the electromagnetic spectrum. It is a common practice in horticulture to manipulate specific plant physiological responses, but to date has only received minimal attention in viticulture. The potent odorant 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) is of particular relevance for aged Riesling wine, which are also known to be impacted by the magnitude of bunch zone light exposure during berry development. Hence, in this study, the effect of photoselective bunch zone shading on the formation of TDN in wine was investigated across two consecutive growing seasons. Applying red, black or green shade cloth (SC) to the bunch zone provided unique bunch zone light environments and yielded distinct differences in grape and wine composition compared with the unshaded control. Overall, bunch zone shading through shade cloth was effective in reducing overall photosynthetically active radiation compared to the control and the photoselectivity of the SC treatments differently affected a number of grape and wine measures. Fruit yield was somewhat but not significantly lower under black SC treatments, while juice pH was increased in grapes grown under green and black SC across both vintages compared to the control. Both grape sugar accumulation (P = 0.035) and ammonia nitrogen (P = 0.043) showed evidence of treatment effects, although with low F-statistics (4 and 3, respectively). Measures of hydrolytically released TDN in juice and free TDN concentrations in wine were lower in SC treatments. Unexpectedly, sensory descriptive analysis of the wines demonstrated that increased ‘kerosene-like’ aroma was not consistently associated with free TDN concentrations in wine. In summary, photoselective bunch shading was demonstrated to be an effective method for manipulating grape and wine outcomes and may aid in overcoming viticultural obstacles and quality impacts associated with climate change.

Target-Guided Isolation of Progenitors of 1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) from Riesling Wine by High-Performance Countercurrent Chromatography.

High-performance countercurrent chromatography (HPCCC) was used for the target-guided isolation of precursors of 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) from Riesling wine. In separated HPCCC fractions of an Amberlite® XAD®-2 extract obtained from a German Riesling, TDN-generating fractions were identified by the acid-catalyzed hydrolysis of the progenitors at pH 3.0 and subsequent HS-GC-MS/MS analysis. The presence of multiple TDN-generating precursors in Riesling wine could be confirmed. From polar HPCCC fractions (11–13 and 14–16), 3,4-dihydroxy-7,8-dihydro-β-ionone 3-O-rutinoside and 3,4-dihydroxy-7,8-dihydro-β-ionone 3-O-β-d-glucopyranoside were isolated as major TDN-precursors at a sufficient amount for structure elucidation by NMR spectroscopic studies. In the medium polar HPCCC factions (27–35), enzymatic hydrolysis liberated the aglycones 3-hydroxy-β-ionone and 3-hydroxy-TDN in minor amounts. In further less polar TDN-generation fractions (36–44 and 45–50), glycosidic progenitors were absent; instead, a minor TDN formation most likely from non-conjugated constituents was observed.

CREATION OF SENSORY PROFILES OF RIESLING WINES FROM EUROPE, AMERICA AND OCEANIA AND THEIR COMPARATIVE CHARACTERISTICS

Effective work at the winery is possible only if the final result is taken into account. Riesling wines have a different organoleptic profile depending on the country of cultivation, zone, climate and weather conditions. High temperatures affect the high concentration of TDN in the berry, more moderate forms herbal, fruit and mineral descriptors. Of course, work at the winery is also important. This work presents the results of the research of seven Riesling wines from different countries of the world: France, Italy, Germany, Austria, Ukraine, New Zealand and Australia. All wines are from the same harvest year and are made using similar technology. Looking at the possible difference in grape clones, terroir and yeast, the author understands the discrepancy in descriptors, but the main criteria for wine quality are objective indicators. The most important indicators of the quality of wines are balance and aftertaste, the whole range of descriptors and indicators of taste, in the end, should answer two questions – how good is the balance and long aftertaste. The higher the score, the higher the quality of the product. The analysis carried out by the author shows that the Riesling wines produced in New Zealand, Austria and Germany received the highest indicators of balance and aftertaste. These same samples received the highest points according to the scoring method, in addition, the first two have the highest ratings in the categories “aroma intensity” and “taste intensity”. Another important criterion of wines from the Riesling variety – minerality – is also the largest in the above three wines. The Ukrainian sample turned out to have good descriptors of berry, floral and stone aromas, and has good acidity. These data may indicate the peculiarity of the Ukrainian terroir, but still require additional research. The obtained data can be used to improve the organoleptic profile of Riesling wines grown in Ukraine.

Chemo-diversity of chiral monoterpenes in different styles of Riesling wine from different regions

Monoterpenes are important characteristic compounds for aromatic white wines, including Riesling, but their enantiomer composition has been little explored in wine. Enantiomers can differ depending on region and style, as they are sensitive to environmental factors, and thus could be used for wine authentication. Thirteen monoterpene isomers were quantified by HS-SPME-MDGC-MS in fifty-four commercial Riesling wines from three wine styles (dry, medium dry and medium sweet) and four well-established wine-growing regions in Germany, France (Alsace) and the USA (New York and Oregon). Significant differences were found for nine out of the 13 enantiomers among different regions and eight enantiomers among styles. X-Y scatterplots of enantiomer pair concentrations, with excellent fitted lines, implies low variation of enantiomeric ratios from each region. The study suggests that wines from different regions and styles were differentiated by chiral monoterpene profiles. Chiral monoterpene analyses could provide supporting information in Riesling wine authentication by offering an objective measure of flavour quality, as these compounds are key compounds for Riesling aroma and flavor.

Implicit prices of attributes of fine German Riesling: magnitude and heterogeneity

PurposeThis study aims to analyse how wine attributes affect prices of fine German Riesling wines, provide estimates of the magnitude and heterogeneity of the attributes' implicit prices and draw conclusions on the pricing of fine wine and the research methodology.Design/methodology/approachImplicit prices of attributes of fine German Rieslings are estimated with fixed-effects regressions and their heterogeneity across quantiles of the conditional price distribution is tested with quantile-regression techniques. The analysis is based on a unique online data set for prices and characteristics of collectible wines.FindingsQuality levels according to the German Prädikat system, additional quality awards for exceptional quality, the wine region, age or vintage as well as ullage and the bottle condition are relevant when explaining the price of cellarable wine. Additionally, the influence of the firm's individual reputation is very strong. Relative price premiums for some major attributes of fine German Riesling change significantly across quantiles of the conditional price distribution. Other attributes are characterised by a rather stable relative (but not absolute) price premium.Originality/valueThis is, to the best of our knowledge, the first hedonic price analysis which concentrates exclusively on fine German Riesling wine. By applying both classical and quantile regressions, the authors are able to derive new insights on quality-price linkages in this growing segment of collectible wine and on the research methodology.

Effect of Cold Stabilization Duration on Organic Acids and Aroma Compounds during Vitis vinifera L. cv. Riesling Wine Bottle Storage.

During the storage of wines in bottles, especially white wines, tartrate crystallization often occurs, which reduces the commercial value of the wines and therefore needs to be avoided by performing cold stabilization treatments before bottling. However, whether different cold treatment durations impact the quality of a wine’s aroma has not yet been of special concern. This research was conducted at an industrial scale to explore how cold treatments at −5.3 °C for 10 to 15 days impact the organic acids, aroma compounds, and sensory quality of Riesling dry white wines, and the variation was documented at the end of treatment, and at 6 and 12 months of bottle storage. The results showed that cold treatments significantly reduced tartaric acid concentrations and significantly affected the concentrations of most aroma components in the wines only after 12 months of bottle storage, including the main components of esters, norisoprenoids, terpenoids, and furfural. Moreover, the concentrations of some components showed an increasing trend with the bottle storage, especially 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), the characteristic volatile of Riesling wine, suggesting that an acidic condition resulting from cold treatment might facilitate the conversion of some aroma precursors into volatiles. In conclusion, cold stabilization treatments, within limits, can improve tartaric acid stability and could promote the conservation of aroma compounds during bottle storage without adversely affecting the aroma profile of the wines.

Application of Chitosan-Lignosulfonate Composite Coating Film in Grape Preservation and Study on the Difference in Metabolites in Fruit Wine

In order to solve the global problem of fruit rotting due to microbial infection and water loss after harvest, which leads to a large amount of food waste, this experiment uses degradable biological composite coating to prolong the preservation period of grapes. Chitosan (CH) and Lignosulfonate (LS) were used as Bio-based film materials, CH films, 1% CH/LS films and 2% CH/LS biomass composite films were synthesized by the classical casting method and applied to grape preservation packaging. Its preservation effect was tested by grape spoilage rate, water loss rate, hardness, soluble solids, titratable acid, and compared with plastic packaging material PE film. At the same time, 1H NMR technology combined with pattern recognition analysis (PCA) and partial least squares discriminant analysis (PLS-DA) was used to determine the nuclear magnetic resonance (NMR) of Cabernet Sauvignon, Chardonnay and Italian Riesling wines from the eastern foothills of Helan Mountain to explore the differences in metabolites of wine. The results of preservation showed that the grapes quality of CH films and 2% CH/LS coating package is better than the control group, the decay rates decreased from 37.71% to 21.63% and 18.36%, respectively, the hardness increased from 6.83 to 10.4 and 12.78 and the soluble solids increased from 2.1 in the control group to 3.0 and 3.2. In terms of wine metabolites, there are similar types of metabolites between cabernet Sauvignon dry red wine and Chardonnay and Italian Riesling dry white wine, but there are significant differences in content. The study found that 2% CH/LS coating package could not only reduce the spoilage rate of grapes, inhibit the consumption of soluble solids and titratable acids, but also effectively extend the shelf life of grapes by 6 days.

Physico-chemical analysis of the Rhine Riesling wines produced in Plešivica-Okić wine region during three consecutive years

Analizirani uzorci vina sorte Rajnski rizling iz vinogorja Plešivica-Okić proizvedeni su tijekom tri uzastopne godine (2009., 2010. i 2011.) na jednom obiteljskom gospodarstvu. Koncentracije alkohola, ukupnih i hlapljivih kiselina, ukupnog SO2 , glicerola i reducirajučih šećera u analiziranim vinima u skladu su sa zakonskim propisima. Uočen je izražen utjecaj klimatskih uvjeta na kemijski sastav analiziranih vina.

Wine Storage at Cellar vs. Room Conditions: Changes in the Aroma Composition of Riesling Wine.

Storage temperature is one of the most important factors affecting wine aging. Along with bottling parameters (type of stopper, SO2 level and dissolved O2 in wine), they determine how fast wine will evolve, reach its optimum and decline in sensory quality. At the same time, lowering of the SO2 level in wine has been a hot topic in recent years. In the current work, we investigated how Riesling wine evolved on the molecular level in warm (~25 °C) and cool (~15 °C) conditions depending on the SO2 level in the wine (low, medium and high), flushing of the bottle’s headspace with CO2 and three types of stoppers (Diam 30, Diam 30 origin and Diam 5) with different OIR levels (0.8–1.3 mg) and OTR levels (0.3–0.4 mg/year). It was demonstrated that the evolution of primary and secondary aromas, wine color and low molecular weight sulfur compounds (LMWSCs) during the two years of aging mainly depended on the storage temperature. Variation in the SO2 level and CO2 in the headspace affected mostly certain LMWSCs (H2S, MeSH) and β-damascenone. New aspects of C13-norisprenoids and monoterpenoids behavior in Riesling wine with different levels of SO2 and O2 were discussed. All three types of stoppers showed very close wine preservation properties during the two years of storage. The sensory analysis revealed that, after only six months, the warm stored wines with a low SO2 level were more oxidized and different from the samples with medium and high SO2 levels. A similar tendency was also observed for the cool stored samples.

The effect of ripening rates on the composition of Cabernet Sauvignon and Riesling wines: Further insights into the sugar/flavor nexus

Grape ripening accelerates under warmer and drier conditions, resulting in the accumulation of sugars (‘technological’ maturity) being decoupled from phenolic and aromatic composition. This study investigated the effect of different rates of ripening on the composition of Cabernet Sauvignon and Riesling wines. Manipulating crop load and irrigation led to distinct rates of berry ripening. In the resulting wines, reduced crop load affected the aroma composition, altering the profile and abundance of grape-derived compounds and fermentative esters. Phenolic composition was impacted by the irrigation regime, with color and tannin increased by late season irrigation. In Cabernet Sauvignon, the combination of treatments led to the largest ripening delay (3 weeks), resulting in less green and more fruity compounds, and improved phenolic composition. By mapping grape and wine metabolites and exploring their relationship, the outcomes of this study demonstrate the importance of ripening rates in determining wine quality.