OXYGEN ADDITIONS DURING VINIFICATION AND THE IMPACT ON WINE. 1ST PART

Pasteur wrote in 1864, “wine is made, and matures, essentially transforming itself from a young wine to an older wine almost exclusively by the influence of air”. Yet, modern enology has largely side-stepped this fundamental parameter that is oxygen for a long time. All along the process of making the wine there is a direct influence of oxygen that relates directly to how the final wines’ organoleptic profile will evolve over time. The contribution of oxygen is utilized by the must, by the wine and by the microorganisms that develop in the wine, notably yeast, Up until now, analysis of oxygen was the domain of the laboratory. The analysis needed to be done quickly. Today, we have access to reliable equipment that can take measurements directly at the tank. During the course of fermentation, the use of oxygen by the wine is negligible. Afterwards oxygen additions are made at two levels: during dynamic process’ (such as pumping, filtering and cold stabilization) OR every time the wine is displaced by gravity or pumping, an oxygen transfer can occur OR during static phases, such as ageing in tanks, in barrels or in bottle. Effect of various stabilization techniques on oxygen addition are discussed. In relation to wine filatration importance of the overall volume being treated was documented. At the bottling phase, oxygen can affect each bottle differently, depending on the cork and other small factors contributing to this heterogeneity on a bottle basis, even within a particular lot. These aspects will be written about in greater detail in the second part of this article.