Australian Journal of Grape and Wine Research最新文献

Many varietal aromas of wine are located in the berry skin. In the present study, we evaluated four important Austrian grape varieties: Grüner Veltliner, Sauvignon Blanc, Traminer, and Pinot Blanc. We assessed whether prefermentation skin contact, fermentation with the skin (only for Grüner Veltliner), and stabulation (lees stirring; only for Sauvignon Blanc, Traminer, and Pinot Blanc) could enhance the varietal aromas of the different grape cultivars. The aim was to intensify the varietal aromas without extracting the undesirable phenols. We performed a detailed analytical characterisation of approximately 100 volatile and phenolic compounds as well as a sensory characterisation. Although mash fermentation significantly increased the spicy aromas of Grüner Veltliner, which are affected by climate change (especially the sesquiterpene rotundone), it markedly decreased the fruitiness and increased the bitterness; therefore, it cannot be recommended for this cultivar. For Sauvignon Blanc, stabulation is a possible option; the varietal aromas (thiols and methoxypyrazines) were increased in the final wines of these variants. For Pinot Blanc and Traminer, prefermentation skin contact yielded the best results: for Traminer, it produced the highest content of monoterpenes (especially z-rose oxide), and for Pinot Blanc, it produced the highest content of ethyl esters. To summarise, stabulation will not completely replace classic skin contact, and mash fermentation is certainly not an alternative for the production of standard Grüner Veltliner wine. However, additional investigations are necessary with regard to other grape varieties, terroirs, and vintages before we can make final recommendations.

Rootstocks are used in viticulture to manage plant pests and diseases, particularly phylloxera and root-knot nematodes, and to improve grape and wine production. A wide range of rootstocks are commercially available, making selecting the optimal rootstock a difficult decision. In particular, distinct rootstock genotypes may manifest varying degrees of tolerance or resistance to abiotic stress, necessitating meticulous consideration during the rootstock selection process. This article reviews characteristics of various commercial rootstocks, as well as rootstocks being developed in recent years. This review further discusses responses of rootstocks to drought, soil nutrients, and soil pH. This review mainly focuses on influence of rootstocks on physiology characteristics of grafted scions rather than berry yield and quality. The breadth of this review benefits both researchers and practitioners by providing comprehensive summery of rootstocks to inform selection and to guide future research.

The term minerality is often used to describe high-quality still white wines produced in cooler regions, such as Chablis. What minerality means in sensory terms and what is responsible for its presence is the subject of debate, however. This study explored the concept of minerality by analysing 16,542 Chablis Premier Cru tasting notes entered into CellarTracker between 2003 and 2022 on wines three to seven years old, together with weather, topography, and soil data for the Chablis area. The top three words used to describe Chablis Premier Cru wine were citrus, minerality, and acidity. Mentions of minerality declined between 1999 and 2019 vintages, whereas those of acidity, salinity, floral, orchard fruit, and stone fruit increased. The trends for minerality and salinity were slightly stronger with the year of tasting (2005 to 2022) than vintage. Bigram analysis indicated that consumers were more than 1.5 times as likely to refer to a stony kind of minerality as a saline one and only rarely smoky minerality. Use of the term minerality was correlated with growing season temperature and sunshine hours (negatively with each), as well as vineyard aspect (negatively with percentage vineyard area facing South or South-West), but not with Kimmeridgian soil type. The results imply that soils and geology are not a principal source of minerality in Chablis wine, but growing season warmth and sunshine are relevant to minerality. There is no simple explanation of minerality in Chablis wine; however, the recent decline in the use of this term for Chablis wine may be a consequence of three factors in combination: (i) it has become less fashionable; (ii) consumers are choosing “saline” instead of “mineral” when appropriate, but retaining it for “stony” sensations; and/or (iii) warming from climate change has reduced minerality.

The present work analyzes the feasibility of using solar water heating systems (SWHS) to supply the hot water required in the winemaking industries. The hot water demand of the sector was characterized by selecting patterns that encompass the wide range of existing casuistry. After determining the production potential of the SWHS by using an experimental system, 22500 energy simulations were carried out, combining different locations, energy prices, and prices of the necessary investment. The results demonstrate that the seasonality and irregularity of a winery’s demand pattern drastically condition the viability and profitability of SWHS. In wineries with high demand, which are relatively uniform throughout the year, the solar system with optimized design achieves energy consumption reductions between 32% (low radiation) and 52% (high radiation), with payback between 4.3 and 7.2 years. On the other hand, in wineries with highly seasonal consumption, SWHS are not profitable even in very favorable cases.

For wine grape producers, achieving an optimal balance between vegetative and reproductive growth is a key factor in producing high quality fruit and meeting production quotas. This balance is often measured as the leaf-area-to-yield ratio. To increase this ratio, producers often use “cluster thinning” (CT), a management practice involving a selective removal of grape clusters from vines. Despite this, no consensus has been established regarding the optimal CT timing and severity for consistently improving fruit composition. The objective of this work was to identify whether CT “timing” (bloom, pea-size, lag phase, and veraison) or “severity” (15–35%, 36–55%, and 56–75%) influences yield and fruit composition. To achieve this objective, a meta-analysis of 160 publications on CT in grape was reduced to 78 studies via 10 data curation steps. We reported the influence of CT timing and severity on yield and fruit composition, as well as their impact on the yield-fruit composition tradeoff. First, CT timing showed little influence on fruit composition, which provides producers with greater flexibility when using this practice. Second, CT severity was impactful on improving fruit composition (TSS and pH); only the moderate range (36–55%) was effective. In conclusion, wine grape composition is more influenced by CT severity than timing. This work has important implications for grape producers and their approach to improving grape composition.

Background and Aims. Botrytis bunch rot (BBR) in cool temperate climates is a key constraint to the consistent supply of grapes to winery specifications. BBR severities have been correlated with specific environmental conditions; however, data-driven applications intended to support crop protection decisions are restricted in access and/or of unknown commercial value. The aims of this study were to evaluate variables providing within-vineyard awareness of BBR risk in Riesling vines. Methods and Results. Descriptors of BBR epidemics from eight site years, 2009–2014, were developed for vine areas of ∼0.5 ha within two regions of Tasmania with different climates. Two variables using the daily Bacchus index, from crop stage E-L 19 to E-L 31 or 34, accounted for >80% of the variance in the final mean BBR severity. A BBR risk index (BBR-I), incorporating the mean daily Bacchus index from E-L 19 to E-L 31 and the median daily vapour pressure deficit of air at 15 : 00 during the late-season interval, accounted for up to 99.5% of the variance in the final mean BBR severity. The late-season interval (days) or median daily RH (%) at 15:00 in the same period accounted for 86.4 or 83.3% of the variance. Spatial variability of BBR severity mapped in 4.8 ha of Sauvignon Blanc in 2018-19 confirmed the need to apply BBR risk indicators at an appropriate spatial scale. Conclusions. Environmental variables with biological relevance served as indicators of BBR risk at the study sites and have the potential to discriminate BBR risk among production regions in Tasmania. Significance of the Study. Study findings are expected to support the development of applications that raise awareness of BBR risk at an appropriate spatial scale for in-season adaption of crop protection, diagnosis of crop protection efficacy, and/or site selection decisions. Accompanying formulae with sample data in Microsoft® Excel will support transitions to automated data analyses.

Although vertical shoot positioned (VSP) training systems, either cane- or spur-pruned, are adopted in the great majority of the vineyards worldwide, the lianas nature of the grapevine and the presence of long and flexible canes confer high plasticity and render structural and pruning changes quite easy. The focus of this review is if, in light of the most consistent features triggered by global warming (e.g., longer growing season, earlier phenology, faster ripening, higher incidence of overheating stress and sunburn, higher frequency of extreme weather events), the type and management of training systems should also be reconsidered. We surveyed the main methods to assess training system efficiency and the current attempts and outlook toward exploiting the training system as an adaptation tool to climate change. For the latter, we considered 12 main trellis types and scored them based on climate-related features and general traits such as vigor, yield control, susceptibility to fungal diseases, and suitability according to wine types (still or sparkling). The resulting balance of positive and negative recommendations leads to a re-evaluation of either old, nonmechanizable trellis types (e.g., Raggi-Bellussi and pergola types), divided canopy systems (e.g., GDC and Scott Henry) or, among the single canopy types, of the single high wire (SHW) trellis. However, historical systems traditionally used by best regions and producers (e.g., goblet and VSP either cane- or spur-pruned) overall show less adherence to the chosen evaluation criteria. To direct future evolution of training systems, regardless of the broadly shared need for suitability to partial or full mechanization, the scenario looks different depending on cool and temperate (warm) areas. The former experiences an outburst of interest as warming is broadening growing areas and affordable genotypes. Under such circumstances, training systems should help accelerate or favor the ripening process through vigor control and lower yield, better cluster exposure, and nonlimiting leaf area-to-fruit ratio. Whereas, in warm areas that are now becoming sub-tropical areas in the worst cases, the SHW gains credit as compared to goblet and traditional VSP. The latter requires an increasing number of canopy manipulations and a rethinking of some planting choices to accommodate the needs of slower and more delayed ripening, more cluster shading, and higher cordons, the latter reducing the probability of incurring significant frost damage.

This study investigates consumer perceptions and acceptance of innovative strategies implemented to counter the effects of climate change in the wine industry. The acceptance of wines derived from grapes grown using four different vineyard management practices—kaolin application, use of plant growth regulators, introduction of resilient rootstocks, and fungus-resistant grape varieties (PIWI)—is analyzed. Utilizing a latent profile analysis, the study identifies five distinct consumer profiles, each displaying unique sensitivities and perceptions towards climate change threats. The findings reveal notable variations in consumers’ willingness to accept these innovations. Additionally, the study offers insights into how these preferences influence the marketability of wines produced using these innovative techniques. The overall results depict heterogeneous acceptance of these practices. Consumers seem more inclined to choose wines derived from vines with innovative rootstocks and those treated with kaolin. The acceptance for PIWI varieties and PGR is comparatively marginal. The outcomes of this study provide valuable insights for winegrowers, policymakers, and other industry stakeholders on effectively implementing and communicating these solutions. Overall, the research findings contribute significantly to understanding consumer behavior within the context of climate change in the wine industry, presenting substantial implications for sustainable viticulture practices and wine marketing strategies.

Background and Aims. Vineyard performance is impacted by water availability including the amount and seasonality of rainfall, evapotranspiration, and irrigation volume. We benchmarked water-limited yield potential (Yw), calculated yield gaps as the difference between Yw and actual yield, and explored the underlying environmental and management causes of these gaps. Methods and Results. The yield and its components in two sections of 24 Shiraz vineyards were monitored during three vintages in the Barossa zone (GI). The frequency distribution of yield was L-shaped, with half the vineyards below 5.2 t·ha⁻¹, and an extended tail of the distribution that reached 24.9 t·ha⁻¹. The seasonal ratio of actual crop evapotranspiration and reference evapotranspiration was below 0.48 in 85% of cases, with a maximum of 0.65, highlighting a substantial water deficit in these vineyards. A boundary function relating actual yield and seasonal rainfall was fitted to quantify Yw. Yield gaps increased with an increasing vine water deficit, as quantified by the carbon isotope composition of the fruit. The yield gap was smaller with higher rainfall before budburst, putatively favouring early-season vegetative growth and allocation to reproduction, and with higher rainfall between flowering and veraison, putatively favouring fruit set and berry growth. The gap was larger with higher rainfall and lower radiation between budburst and flowering. The yield gap increased linearly with vine age between 6 and 33 yr at a rate of 0.3 t·ha⁻¹·yr⁻¹. The correlation between yield gap and yield components ranked bunch weight ≈ berries per bunch > bunch number > berry weight; the minimum to close the yield gap was 185,000 bunches ha⁻¹, 105 g bunch⁻¹, 108 berries bunch⁻¹, and 1.1 g berry⁻¹. Conclusions. Water deficit and vine age were major causes of yield gaps. Irrigation during winter and spring provides an opportunity to improve productivity. The cost of dealing with older, less productive vines needs to be weighed against the rate of increase in yield gap with vine age. Significance of the Study. A boundary function to estimate water-limited yield potential returned viticulturally meaningful yield gaps and highlighted potential targets to improve vineyard productivity.

Background and Aims. This work investigated the TCA permeability of twelve types of commercial bottle closures during 24 months of bottle storage in the d₅-TCA-contaminated atmosphere: medium pollution (max. ∼50 ng/L of d₅-TCA in the air) and high pollution (max. ∼500 ng/L of d₅-TCA in the air). Methods and Results. The d₅-TCA content of wine samples and bottle closures was monitored by GC-MS analysis, and the closures of one group (comprising natural corks, agglomerated stoppers, and BVS Tin Saran™ screw caps) were found to be excellent barriers against airborne d₅-TCA, i.e., no contaminant was detected in wine under any storage conditions. In contrast, a second group of closures (synthetic stoppers with low OTR, BVS Saranex™, and plastic body screw caps) allowed permeation of d₅-TCA, polluting the wine when air contamination was high, albeit no d₅-TCA was detected in wines following storage under medium air contamination conditions. A third group of closures (synthetic stoppers with medium and medium + OTR, MCA screw caps, and glass stoppers) allowed d₅-TCA to accumulate in wine under both medium and high contamination environments. Conclusions. Some commercial bottle closures were found to permeate airborne d₅-TCA, thereby contaminating bottled wine under certain storage conditions. Significance of the Study. This work provides the wine industry with insight into the potential for postbottling contamination of wine by airborne TCA.