The impact of metal speciation on the development, shelf-life and sensory properties of wine

The aim of this project is to develop a better understanding of how the presence of different metal species can influence ageing of bottled wine and provide options to minimise detrimental influences of metals through wine production processes. Metal ions are naturally present in grapes and wine and are often added during the winemaking process to reduce formation of volatile sulphur compounds. Lack of understanding of the relationship between concentrations and their effects and of the reactivity of the metals, means that wine ageing and shelf life in bottle cannot be reliably predicted and addition rates are not optimal. The current project tackles the role of these different metal species and metal concentration ratios on colour and flavour development in wine. It aims to understand more deeply the consumption of sulphur dioxide by oxygen in red and white wines, why the rate varies from wine to wine and the role of metal species in this variation. The influence of ascorbic acid, a common wine additive, on the stability and activity of copper(I) sulphide, will be determined, and a link established between metal speciation and steps in the wine production process that allow efficient removal of metals from wine and juice.