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Sustainable enhancement of autochthonous wine grapes in mountain areas

Risultati finali

The procedure to apply in the management of a research work on autochthonous wine grapes in different areas are very complex. - Selection of autochthonous wine grape varieties and identification of test fields In each area involved in the project, on the basis of preliminary surveys, literature information and previous experiences of SMEs and RTDs involved, the selection of minor wine grape cultivars, to be investigated from the pool of autochthonous grape varieties, has to be done paying attention to their dimension (able to produce at least 300 kg of grape) and their general situation. - Protocols definition It very important to define with attention the experimental protocols, that defined the methodologies to applied in field and in wine making. Partners contribute and agree with them. - Survey of field Ampelographic (morphological) descriptions has to be carried out with a common system, images of the major vine organs (shoot, adult leaf and bunch) provided. Such ampelographic documentation is essential for variety identification and is required for including a grape varieties into National Grape Varieties Catalogues. Survey on phenological phases (bud burst, flowering, veraison and grape ripening), agronomical traits (fertility, vine vigour assessed by winter pruning weight, yield, tolerance or susceptibility to pests and diseases) and grape technological characteristics (bunch and berry weight and features, juice chemical composition) of each selected grapevine variety has to be carried out. As to the progress in grape ripening, berry samples collected weekly from 1-2 weeks after veraison to vintage and the obtained juice analysed for its sugar and acidic components. When the grapes reach physiological ripening, detailed analyses conducted on their composition, in order to guide the winemaking process completely. - Winemaking The winemaking is done separately for every single variety of grapes on small or medium scale. According to the area and the cultivar a quantity of at minimum 300 kg of grapes per variety has to be processed. Grape of each single cultivar has to be winemaking processed following standardized steps for red wine production: grape crushing and destemming, inoculation with active dry yeast, running-off at complete fermentation, addition of malo-lactic bacteria starter and tartrate stabilization and for white wines production: crushing, juice extraction with pressing, clarification of cooled must, inoculation with active dry yeast, running-off at complete fermentation and tartrate stabilization. Besides routine chemical tests, that accompany the various phases of the working process, detailed analyses of the composition of finished wines has to be carried out, including phenolic and aromatic compounds. - Sensory evaluation Sensory evaluation of wines has to be performed according to two approach methods: the Quantitative Descriptive Analysis (QDA) and the Consumer Test. - Cooperation between partners In the phases concerning surveys in the fields and winemaking processes, SME proposers has to be helped by staff from the RTD performers in the same area. The RTD-performers support SME operators by instructing them on the most suitable and correct procedures and methodologies to adopt in order to carry out surveys and analysis of the cultivars in question. The SMEs who take part in the project are learning the use of the most suitable methodologies to improve the quality of their work and their products. - Coordination meetings During the coordination meetings experimental protocols has to be discussed and agreed among participants and the administrative aspects has to be clarified to better coordinate the reporting on project progress. - Exploitation and dissemination activities Exploitation is an important issue of the project: actions dedicated to the diffusion of the obtained RTD results has to be organized.
In each mountain area involved in the project the selection of minor wine grape cultivars, to be investigated from the pool of autochthonous grape varieties, was done following the criteria below listed: - Grapevine varieties at present neglected (used to a minor extend) whose cultural and technological potential is unknown or hardly known. - Grapevine varieties whose cultural and/or technological traits acquired so far can be considered of interest for development and exploitation. - Grapevine varieties exempt from known growing faults. - Grapevine varieties available (in a sufficient number of adults, yielding vines) in experimental or commercial vineyards located in suitable sites. In this project was selected 36 wine grape cultivars, including several local major varieties as reference. In each area test fields was accurately choose taking care of their dimension and their general situation. Data on climate and soil conditions of each one was taken. Ampelographic (morphological) descriptions were carried out also in the second year for the selected varieties. The method used was in accord to primary and secondary descriptors priority list requested within the European Vitis Database (GENRES 081 project: http://www.genres.de/vitis/vitis.htm). Images of the major vine organs (shoot, adult leaf and bunch) were provided. In both years of work, survey on phenological phases (bud burst, flowering, veraison and grape ripening), agronomical traits (fertility, vine vigour assessed by winter pruning weight, yield, tolerance or susceptibility to pests and diseases) and grape technological characteristics (bunch and berry weight and features, juice chemical composition) of each selected grapevine variety were carried out. As to the progress in grape ripening, berry samples was collected weekly from 1-2 weeks after veraison to vintage and the obtained juice analysed. The results obtained in the two years were compared. When the grapes reach physiological ripening, detailed analyses were conducted on their composition, in order to guide the winemaking process completely. The winemaking was done separately for every single grape variety. In general, a common methodology was agreed upon partners to obtain red and white wines (with only an exception for special wines). Whenever it is possible to compare scientifically the wines obtained from various working groups, standardized methods were adopted and identical additives used. A suitable wine-making flow-chart for red and white wines to be adopted by all participants (SME and RTD performers in each of the 6 mountain areas) was defined in light of already acquired experience. Grape of each single cultivar was winemaking processed following standardized steps for red wine production: grape crushing and destemming, inoculation with active dry yeast, running-off at complete fermentation, addition of malo-lactic bacteria starter and tartrate stabilization and for white wines production: crushing, juice extraction with pressing, clarification of cooled must, inoculation with active dry yeast, running-off at complete fermentation, possible inoculation with malo-lactic bacteria and tartrate stabilization. Besides routine chemical tests, that accompany the various phases of the working process, detailed analyses of the composition of finished wines was carried out, including phenolic and aromatic compounds. Sensory evaluation of wines was performed according to two approach methods: the Quantitative Descriptive Analysis (QDA) and the Consumer Test. The QDA was performed during two years. According to ISO 6564 the 2003 wines were examined by three panels. Each panel examined all the wines and defined the sensory descriptors for each wine. A Quantitative Descriptive Card with these descriptors was then defined. The wines produced in the first year of study were subjected to a Consumer test during the Turin wine exhibition “Salone del Vino”. For each sample were evaluated colour, odour and taste. An overall evaluation was also asked at the end of tasting. For each parameter a nine point hedonistic scale was used. The Sensory Cards, defined in the first year of study, were used to evaluate all 2004 vintage wines, at the end of the experimental period. For this analysis the trained panels of each RTD were used. By mean of values computed for each descriptor among panellists and panels the sensory profiles were defined for each wine produced from single autochthonous grape varieties.
In each year of study, 36 different experimental single variety wines were produced: 26 from autochthonous grape varieties and 10 from local major varieties as reference. The wines produced following the winemaking protocols defined were completely analyzed in different phase of production, bottled and used for sensory analysis activities. The bottles yet available will be used to verify the evolution of this kind of wines in the medium long period. The aim is to improve the quality of products and to find favour with consumers.