Proposal of zonification and characterization of terroirs in the Yalde-Najerilla-Uruñuela vine growing area (DOC Rioja, Spain), based on the soil influence

The Grenache Noir grape variety, due to its originality and its representativeness, contributes very directly to the quality and typicality of the wines of the Rhône Valley. It is generally appreciated for its varied aromatic palette and for the roundness and suppleness it gives to wines. Since 1995, the Rhodanien Institute has set up a network of reference plots representative of the different types of terroir present in the southern zone of the Côtes du Rhône Appellation (TRUC, 1997; VAUDOUR et al, 1996 ) . Publications on the aromatic composition of grapes and wines are very abundant, but only a few articles have appeared on the Grenache grape variety PAUMES et al., 1986).

“Pinking” is a term used to define an abnormal pink coloration assumed by white wines in certain cases. Despite the are many hypotheses about the causes of this phenomenon, pinking still represents an issue for the wine industry. In the absence of reliable preventive strategies, wineries often rely on treatments such as charcoal fining, which is also negatively impacting wine aroma. This study aims at evaluating the potential of different fining agents based on animal or vegetal proteins to prevent wine pinking when applied at the level of must clarification. The work was carried out on Lugana wines, which is well-recognised as sensible to pinking problems. METHODS: Two experimental Lugana musts were obtained by applying a standard winemaking protocol and were then clarified with different commercial preparations based on vegetal proteins or casein, alone or in combination with PVPP. A control only using pectolytic enzyme was also prepared. Finings were carried out at 4°C for 16h, and the clear must (200 NTU) was then fermented in controlled conditions.

Botrytis bunch rot occurrence is one of the most important limitations for the wine industry in humid environments. A positive correlation between grapevine growth and susceptibility to fungal pathogens has been found. In theory the effect of grapevine vegetative growth on bunch rot expression results from direct effects (cluster architecture, nitrogen status among others) and indirect ones (via microclimate). However, a reduction in bunch rot incidence can be achieved in some circumstances without major vine growth reduction. The present study was aimed to test the general hypothesis that bunch rot susceptibility is affected by vine vigor, but other factors associated with grapevine vegetative expression could be even more relevant.

Chitosan is a natural polymeric saccharide admitted by EU since 2011 for must and wine clarification, the reduction of some contaminants (e.g. ochratoxin A) and to prevent the development of wine microbialspoilage due to lactic acid bacteria or Dekkera/Brettanomyces yeasts.

Precocity for fruit ripening is a genetically determined characteristic that is highly variable from one cultivar to another. In traditional wine-growing regions of Europe, growers have used this property to adapt the vines to local climatic conditions in order to maximize terroir expression