The project “Vintegro” has received funding from the European Union’s through the Region Tuscany Rural Development Plan (activated measures (16.2, 1.1, 1.2, 1.3). It aims is to produce naturally stable wines with less use of addition and elimination enological technics, reducing the negative environmental impact.
The project deals with the problem of wine instability, and particularly of precipitation of macromolecules (flavanols, flavonols, polysaccharides, proteins). In the setting up phase, the stakeholders of the wine industry indicated this problem as the one that mostly needs innovation. Wine macromolecules are in a state of metastable colloidal equilibrium, and stay in solution till when the equilibrium is broken due to reactions and interactions among them, thee last depending on the environmental conditions and on wine composition. If the equilibrium breaks when the wine is already on the market, the haze that appears in the bottle is cause of refuse by consumers. The wine is therefore object of controversy, with important economic and commercial consequences.
Presently, without the possibility to foresee if a wine will form precipitates in bottle, and in order to avoid risks, the winemakers tend to exaggerate with the stabilizing treatments, being them physical (filtration, cold stabilization etc.) or chemical (bentonite fining, protein fining etc.). These practices are not dangerous for human health, although can deprive the wine of some of its native constituents and involve relevant economic and environmental costs. During the setting up phase, improved and reliable analytical techniques (dynamic light scattering, Z potential) and accelerating methods (climatic chambers, concentration) were identified; through them become feasible the development of a laboratory test able to predict the instability of a wine, through a rapid and inexpensive procedure suitable to be applied at every lot of wine in every phase of its life.