Produce less oxydable wines with low-input tecnologies

Session Enoforum devoted to Oxyless project

The Oxyless project (funded under undermeasure 16.2 by Regione Toscana and under the European partnership for innovation) main objective is to deal with oxidation risk on wine made of Sangiovese grape. It is a good occasion to talk during Enoforum congress (enoforum.eu) about oxygen management from grape to bottle and about cyclic voltammetry as an analytical technic, based on redox systems, that allows, if combined with multifactorial statistical analysis, an innovative approach to the wine oxidation study.

Speakers will be respectively Jean Claude Vidal from INRA – Pech Rouge. Gruissan France (Institut National de la Recherche Agronomique) and Piergiorgio Comuzzo from Udine University, Food science, Environment and Animal sciences department (Di4A).

Oxygen is one of the main factors for wine’s evolution from grape to the consumer’s glass. How to manage the O2 amounts needed at all stages of its life? How to protect wine from unwanted O2 dissolutions?

Different O2 requirements depend on the wine life stages, on the grape variety and the type of wine desired. During winemaking, the enologist must manage the tricky pre-fermentation phase and bring macro quantities of O2 to help the yeasts to finish turning sugar into alcohol. Throughout its aging, the wine will need a few milligrams of O2 to refine. Then with the conditioning, the objective will be to protect the wine as much as possible from the contaminations by the atmospheric O2, in order to control the evolution of its sensory quality and to reduce its sulfites content.

Finally, during the transport and storage of conditioned wines, the O2 ingresses will be regulated by the choice of O2 permeability of the closure in the case of a glass bottle or the total package in the case of a PET bottle or a bag-in-box.

Cyclic voltammetry is an analytical technic which allows the study of redox systems in wines. The voltammogram (obtained graph) enable us to have important information on the behavior of certain chemical families in a solution. This technic has been used to characterize phenolic substances and to study enological antioxidants based on their reducing power. Together with data analysis based on multivariate analysis, the voltammetric approach has allowed to discriminate wines made of various variety as well as to find existing correlation between voltammograms and the oxygen consumption or the wine resistance to oxidation.