Measurement and behaviour of Cu in wine

Copper in wine can accelerate oxidative processes or influence the accumulation of reductive aroma compounds depending on wine storage conditions and oxygen supply. Recent research has shown these reactions can be linked to specific forms of Cu in wine. Traditionally, measurement of total Cu concentration in wine has only been possible for larger wineries, while the measurement of different forms of Cu only available to research laboratories. This presentation will outline colorimetric or adsorptive filtration approaches to allow the determination of total Cu, and its main forms, in wine using methodology that is possible for any winery with a suitable spectrophotometer. The behaviour of Cu forms during wine oxidation and storage in low oxygen conditions is described, along with the link between Cu forms and reductive aroma accumulation. Finally, the targeted removal of different forms of Cu from wine is also described.