Sweet wines with great aromatic complexity obtained by partial fermentation of must from Tempranillo dried grapes

Musts from Tempranillo grapes sun-dried in the Montilla-Moriles region and containing about 450 g sugar/L were treated in four different ways to obtain sweet wine. One treatment mimicked the traditional procedure and involved supplying the must with wine alcohol to avoid the fermentation. The other treatments involved partial fermentation with the autochthonous flora or with two previously selected osmotolerant yeasts (strains CECT 13014 and CECT 13015). Based on their composition in volatile compounds, the wines obtained by fermentation possessed a more complex aroma. Odorant descriptors allowed the following aroma series to be established for the wines: chemical, ripe fruit, green fruit, floral, milky, fresh grass, dry grass, toasted, and rancid. The chemical, ripe fruit, milky, and toasted series were those exhibiting the highest values in all wines. A principal component analysis and a cluster analysis revealed that the wines obtained by fermentation with selected yeasts were very similar and differed from those fermented in the presence of the autochthonous flora or in the traditional manner. Sensory evaluation of the wines by a tasting panel led to the wines obtained by fermentation with selected yeasts being the best scored. Multiple regression analysis was used to relate the punctuation given by a tasting panel with the volatile composition of the wines using as independent variables the most influential aroma series.