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…

Bioclimatic shifts and land use options for Viticulture in Portugal

Land use, plays a relevant role in the climatic system. It endows means for agriculture practices thus contributing to the food supply. Since climate and land are closely intertwined through multiple interface processes, climate change may lead to significant impacts in land use. In this study, 1-km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS)

Co-design and evaluation of spatially explicit strategies of adaptation to climate change in a Mediterranean watershed

Climate change challenges differently wine growing systems, depending on their biophysical, sociological and economic features. Therefore, there is a need to locally design and evaluate adaptation strategies combining several technical options, and considering the local opportunities and constraints (e.g. water access, wine typicity). The case study took place in a typical and heterogeneous Mediterranean vineyard of 1,500 ha in the South of France. We developed a participatory modeling approach to (1) conceptualize local climate change issues and design spatially explicit adaptation strategies with stakeholders, (2) numerically evaluate their effects on phenology, yield and irrigation needs under the high-emissions climate change scenario RCP 8.5, and (3) collectively discuss simulation results. We organized five sets of workshops, with in-between modeling phases. A process-based model was developed that allowed to evaluate the effects of six technical options (late varieties, irrigation, water saving by reducing canopy size, adjusting cover cropping, reducing density, and shading) with various distributions in the watershed, as well as vineyard relocation. Overall, we co-designed three adaptation strategies. Delay harvest strategy with late varieties showed little effects on decreasing air temperature during ripening. Water constraint limitation strategy would compensate for production losses if disruptive adaptations (e.g. reduced density) were adopted, and more land got access to irrigation. Relocation strategy would foster high premium wine production in the constrained mountainous areas where grapevine is less impacted by climate change. This research shows that a spatial distribution of technical changes gives room for adaptation to climate change, and that the collaboration with local stakeholders is a key to the identification of relevant adaptation. Further research should explore the potential of adaptation strategies based on soil quality improvement and on water stress tolerant varieties.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Underpinning terroir with data: rethinking the zoning paradigm

Agriculture, natural resource management and the production and sale of products such as wine are increasingly data-driven activities. Thus, the use of remote and proximal crop and soil sensors to aid management decisions is becoming commonplace and ‘Agtech’ is proliferating commercially; mapping, underpinned by geographical information systems and complex methods of spatial analysis, is widely used. Likewise, the chemical and sensory analysis of wines draws on multivariate statistics; the efficient winery intake of grapes, subsequent production of wines and their delivery to markets relies on logistics; whilst the sales and marketing of wines is increasingly driven by artificial intelligence linked to the recorded purchasing behaviour of consumers. In brief, there is data everywhere!

Opinions will vary on whether these developments are a good thing. Those concerned with the ‘mystique’ of wine, or the historical aspects of terroir and its preservation, may find them confronting. In contrast, they offer an opportunity to those interested in the biophysical elements of terroir, and efforts aimed at better understanding how these impact on vineyard performance and the sensory attributes of resultant wines. At the previous Terroir Congress, we demonstrated the potential of analytical methods used at the within-vineyard scale in the development of Precision Viticulture, in contributing to a quantitative understanding of regional terroir. For this conference, we take this approach forward with examples from contrasting locations in both the northern and southern hemispheres. We show how, by focussing on the vineyards within winegrowing regions, as opposed to all of the land within those regions, we might move towards a more robust terroir zoning than one derived from a mixture of history, thematic mapping, heuristics and the whims of marketers. Aside from providing improved understanding by underpinning terroir with data, such methods should also promote improved management of the entire wine value chain.

Spatial variability of temperature is linked to grape composition variability in the Saint-Emilion winegrowing area

Elevated temperature during the grape maturation period is a major threat for grape quality and thus wine quality. Therefore, characterizing the grape composition response to temperature at a larger scale would represent a crucial step towards adaptation to climate change. In response to changes in temperature, various physiological mechanisms regulate grape composition. Primary and secondary metabolisms are both involved in this response, with well-known effects, for example on anthocyanins, and lesser known effects, for example on aromas or aroma precursors. At the field scale or at the regional scale, however, numerous environmental or plant-specific factors intervene to make the effects of temperature difficult to distinguish from overall variability. In this study, it was attempted to overcome this difficulty by selecting well-characterized situations with differing temperatures.
A long-term study of air temperature variability across several Merlot vineyards in the Saint-Emilion and Pomerol wine producing area found significant temperature differences and gradients at various time scales linked to environmental factors. From this study area, a few sites were selected with similar age, soil and training system conditions, and with repeated and contrasted temperature differences during the maturation period. The average temperature difference during the maturation period was about 2°C between cooler and warmer sites, a difference similar to that expected under future climate change scenarios. In close vicinity to the temperature sensors at each site, grape berries were sampled at different times until full maturity during 2019 and 2020. Also, berries from bunches on either side of the row were analyzed separately, allowing an investigation of bunch exposure effect associated with the coupling of berry temperature and solar radiation. Four replicates of pooled berries for each time – site – bunch exposure combination were obtained and analyzed for biochemical composition. Analyses of variance of the biochemical composition data collected at different sampling times reveal significant effects associated with temperature, site, and bunch azimuth. For instance, anthocyanins in grape skins are clearly influenced by temperature and solar radiation exposure, with up to 30% reduction in warmer conditions.