Inert gases persistence in wine storage tank blanketing
It is common to find tanks in the winery with wine below their capacity due to wine transfers between tanks of different capacities or the interruption of operations for periods of a few days. This situation implies the existence of an ullage space in the tank with prolonged contact with the wine causing its absorption/oxidation. Oxygen uptake from the air headspace over the wine due to differences in the partial pressure of O2 can be rapid, up to 1.5 mL of O2 per liter of wine in one hour and 100 cm2 of surface area1 and up to saturation after 4 hours. The industrial solution consists of inerting the gas space by means of an inert gas blanket to avoid contact with air. This procedure can be done with automatic systems that generate an overpressure of inert gas and are able to respond to variations in the filling level of the tanks. This is not common in most wineries and in order to propose an easy and effective system, nitrogen (N2), argon (Ar), and carbon dioxide (CO2), the commonly used inert gases in the wine industry, together with their mixtures, have been compared. The persistence of a gaseous blanket of the inert gas (O2<0.5%)2 in the ullage space of the tank and its ability to reduce the uptake of atmospheric O2 into the wine were analyzed.
In addition to checking which of the five gases tested provided the best protection over time with a simple application, two different application methods were compared. In a third phase, the economic optimization was studied by reducing the amount of gas on the basis of the ability of almost all of these gases to form blankets due to their higher density than air.
Acknowledgements: ITACyL for their financial support to Actividades de Investigación, Promoción de la Innovación y la Transferencia del Conocimiento en Sectores Estratégicos de Castilla y León: SECTOR VITIVINÍCOLA
1 Peynaud E. (1981) Knowing and Making Wine. Wiley
Issue: ICGWS 2023
Grupo UVaMOX-Universidad de Valladolid. Avda. Madrid 50. 34001 Palencia, Spain