Macrowine 2021
IVES 9 IVES Conference Series 9 Quality of Merlot wines produced from terraced vineyards and vineyards on alluvial plains in Vipava valley, Slovenia (pdo)

Quality of Merlot wines produced from terraced vineyards and vineyards on alluvial plains in Vipava valley, Slovenia (pdo)

Abstract

AIM: Different factors affect the style and quality of wine and one of the most important are environmental factors of vineyard location. The aim of this study was to compare the quality of Merlot wines produced from grapes growing on skeletal and dry soils of terraced vineyards and deep loamy soils of alluvial plains of Vipava Valley, a warm climate winegrowing district in Slovenia.

METHODS: Five vineyards on terraces and five on alluvium plains were chosen. Viticulture parameters such as number of buds, number of clusters and leaf area on each vine were unified in 2019 and 2020 as described in Sivilotti et al. (2020). Stem water potential (SWP) was measured during the season (Deloire and Heyns, 2011). 5 kg of grapes were sampled in triplicates at the time of grape maturity. Basic physicochemical parameters of grapes were determined before microvinification. Microvinifications were analysed after alcoholic and malolactic fermentation. Concentration of total phenols (TP), total anthocyanins (TA), high (HMWP) and low molecular weight (LMWP) proanthocyanidins (PAS) were determined spectrophotometrically as described in Rigo et al. (2000). Moreover, structural characteristics of PAs in wines, i.e. mean degree of polymerisation (mDP), percentage of galloylaton (%G) and percentage of prodelphinidins (%P) were determined by UHPLC-DAD-MS/MS as described in Lisjak et al. (2019) and in Sivilotti et al. (2020). Esters were analysed by GC-MS (Bavčar and Baša Česnik, 2011) and higher alcohols by GC-FID (Bavčar et al., 2011).

RESULTS: SWP was more negative on terraces. According to basic physico chemical parameters and darker seed colour, grapes from terraces showed advanced ripening in comparison to grapes grown in alluvial plains. Wines from terraces had higher concentrations of TA, TP, HMWP, ash and total dry extract in comparison to wines from alluvial plains and PAs reported higher %G. Furthermore, aromatic profiles of wines were also different. In general, higher concentrations of higher alcohols and lower concentrations of esters were detected in wines from terraces.

CONCLUSIONS:

 The Merlot wines from grapes sampled in terraced vineyards differed in chemical composition from those from alluvial plains. In general, wines from terraces had higher polyphenol content, some quality parameters such as ash and total dry extract, structural differences of grape tannins and different profile of some aroma compounds

DOI:

Publication date: September 10, 2021

Issue: Macrowine 2021

Type: Article

Authors

Alenka Mihelčič

Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000 Ljubljana, Slovenia ,Andreja VANZO, Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000 Ljubljana, Slovenia Borut VRŠČAJ, Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000 Ljubljana, Slovenia Paolo SIVILOTTI, University of Udine, via delle Scienze 206, 33100 Udine, Italy Klemen LISJAK, Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000 Ljubljana, Slovenia

Contact the author

Keywords

terraces, alluvial plains, soil, stem water potential, wine quality, polyphenols, volatile compounds

Citation

Related articles…

The impact of leaf canopy management on eco-physiology, wood chemical properties and microbial communities in root, trunk and cordon of Riesling grapevines (Vitis vinifera L.)

In the last decades, climate change required already adaptation of vineyard management. Increase in temperature and unexpected weather events cause changes in all phenological stages requiring new management tools. For example, defoliation can be a useful tool to reduce the sugar content in the berries creating differences in the wine profiles. In a ten-year field experiment using Riesling (Vitis vinifera L, planted 1986, Geisenheim, Germany), various mechanical defoliation strategies and different intensities were trialed until 2016 before the vineyard was uprooted. Wood was sampled from the plant compartments root, trunk, cordon and shoot for analyses of physicochemical properties (e.g. lignin and element content, pH, diameter), nonstructural carbohydrates and the microbial communities. The aim of the study was to investigate the influence of reduced canopy leaf area on the sink-source allocation into different compartments and potential changes of the fungal and prokaryotic wood-inhabiting community using a metabarcoding approach. Severe summer pruning (SSP) of the canopy and mechanical defoliation (MDC) above the bunch zone decreased the leaf area by 50% compared to control (C). SSP reduced the photosynthetic capacity, which resulted in an altered source-sink allocation and carbohydrate storage. With lower leaf area, less carbohydrates are allocated. This for example resulted in a decreased trunk diameter. Further, it affected the composition of the grapevine wood microbiota. SSP and MDC management changed significantly the prokaryotic community composition in wood of the root samples, but had no effect in other compartments. In general, this study found strong compartment and less management effects of the microbial community composition and associated physicochemical properties. The highest microbial diversities were identified in the wood of the trunk, and several species were recorded the first time in grapevine.

From a local to an international scale: sensory benchmarking of PDO wines. Quincy and Reuilly PDO wines (Sauvignon blanc) as a case study (France)

In a collective marketing strategy, the Protected Designation of Origin (PDO) can be used as a quality indicator. To highlight terroir specificities, it is useful to know how the wines are positioned on the local, national or international market from a sensory point of view. This is especially true for a comparison of varietal wines (e.g. Sauvignon blanc). We focus on the case of two closed Loire Valley PDO (France): Quincy and Reuilly. Three distinct tastings were organized. Firstly, at the local level comparing the 2 PDO (11 and 9 wines, 17 professional assessors); secondly at a regional level adding 3 closed PDO: Menetou-Salon, Sancerre and Pouilly-Fumé (3 wines per PDO, 16 assessors) and thirdly at an international level comparing these 5 PDO with Sauvignon Blanc wines coming from South Africa, New Zealand and Chile (1 to 3 wines per PDO, 19 assessors). All the wines were from the 2019 vintage and were considered to have a traditional elaboration process without contact with oak. A sensory descriptive analysis was performed using an aroma wheel allowing to combine a Check-All-That-Apply methodology, often used in sensory benchmarking, with a hierarchical structuration of the attributes. The aim is to facilitate data acquisition in a professional context without common training, to consider the hierarchical relationships among the attributes during the data analysis and to be able to characterize wines with a large range of sensorial variability. We use univariate, multivariate and clustering analyses. Similarities and differences between Quincy and Reuilly PDO wines and other Sauvignon blanc wines were identified. Specific attributes can distinguish the two PDO and different proximities exist with other local PDO, while clear differences were observed compared to international wines. Our study contributes to propose and discuss a method to do a wine sensory benchmarking highlighting sensory specificities linked to origin.

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Soil, vine, climate change – what is observed – what is expected

To evaluate the current and future impact of climate change on Viticulture requires an integrated view on a complex interacting system within the soil-plant-atmospheric continuum under continuous change. Aside of the globally observed increase in temperature in basically all viticulture regions for at least four decades, we observe several clear trends at the regional level in the ratio of precipitation to potential evapotranspiration. Additionally the recently published 6th assessment report of the IPCC (The physical science basis) shows case-dependent further expected shifts in climate patterns which will have substantial impacts on the way we will conduct viticulture in the decades to come.
Looking beyond climate developments, we observe rising temperatures in the upper soil layers which will have an impact on the distribution of microbial populations, the decay rate of organic matter or the storage capacity for carbon, thus affecting the emission of greenhouse gases (GHGs) and the viscosity of water in the soil-plant pathway, altering the transport of water. If the upper soil layers dry out faster due to less rainfall and/or increased evapotranspiration driven by higher temperatures, the spectral reflection properties of bare soil change and the transport of latent heat into the fruiting zone is increased putting a higher temperature load on the fruit. Interactions between micro-organisms in the rhizosphere and the grapevine root system are poorly understood but respond to environmental factors (such as increased soil temperatures) and the plant material (rootstock for instance), respectively the cultivation system (for example bio-organic versus conventional). This adds to an extremely complex system to manage in terms of increased resilience, adaptation to and even mitigation of climate change. Nevertheless, taken as a whole, effects on the individual expressions of wines with a given origin, seem highly likely to become more apparent.

Mapping and tracking canopy size with VitiCanopy

Understanding vineyard variability to target management strategies, apply inputs efficiently and deliver consistent grape quality to the winery is essential. However, despite inherent vineyard variability, the majority are managed as if they are uniform. VitiCanopy is a simple, grower-friendly tool for precision/digital viticulture that allows users to collect and interpret objective spatial information about vineyard performance. After four years of field and market research, an upgraded VitiCanopy has been created to achieve a more streamlined, technology-assisted vine monitoring tool that provides users with a set of superior new features, which could significantly improve the way users monitor their grapevines. These new features include:
• New user interface
• User authentication
• Batch analysis of multiple images
• Ease the learning curve through enhanced help features
• Reporting via the creation of colour maps that will allow users to assess the spatial differences in canopies within a vineyard.
Use-case examples are presented to demonstrate the quantification and mapping of vineyard variability through objective canopy measurements, ground-truthing of remotely sensed measurements, monitoring of crop conditions, implementation of disease and water management decisions as well as creating a history of each site to forecast quality. This intelligent tool allows users to manage grapevines and make informed management choices to achieve the desired production targets and remain profitable.