Misure di ossigeno e cinetiche di consumo durante la vinificazione in rosso

The importance of oxygen in wine-making is well known, but its management requires greater information on the amount of oxygen that dissolves and on the consumption kinetics in aqueous and alcoholic solutions. The aim of this work is to apply a system of measure of dissolved oxygen on real scale and to estimate the concentrations really dissolved in different red-wine-making phases. Starting from 2001 vintage we made vinification trials using Selector System (Gimar Tecno,Occimiano - AL) on different grapes in order to carry out measures during maceration - alcoholic fermentation to obtain data on the dissolved oxygen amount and on the consumption kinetics. During maceration, the oxygen concentration returns to the initial value in variable times, ranging from few minutes to twenty minutes. In the first two-three minutes the oxygen dissolved in the total mass is reduced of 50-60% during the tumultuous fermentation and of the 20-30% at the end of fermentation. Subsequently the decrease is gradual and slower and the oxygen concentration was closed to the instrumental detection limit. The consumption kinetics, apart from the mechanism, can be represented by an exponential equation.