There is growing concern among winemakers about the presence of reductive odours in Pinot Noir wine impacting the perceived quality of the wine and contributing to substantial problems. These odours are caused by the presence of large quantities of volatile sulphur compounds (VSCs) such as hydrogen sulphide, mercaptans/thiols or disulphides, and free sulphur dioxide.

This project is a three-year study investigating vineyard and winemaking procedures contributing to the formation and accumulation of sulphurous off-flavours and aromas in Pinot Noir, ultimately developing a model that will enable knowledgeable winemaking decisions and minimise reductive characteristics.

Although the exact mechanisms of VSC development during winemaking are unknown, there is a suspected link between the usage of elemental sulphur and sulphur-containing compounds in vineyards to combat powdery mildew and the yeast strain used during fermentation. The project’s major goal is to investigate the effect of elemental sulphur on grapes and its potential relation to the development of VSCs responsible for reductive odours in wine. The insights gathered from these studies will pave the way for future studies into establishing focused management techniques and sophisticated technical solutions to successfully eliminate off-odours, with a particular focus on resolving the reductive odours issue in New Zealand Pinot Noir wine.

Project summary

Researchers: Dr Bruno Fedrizzi, University of Auckland

Years: 2021-2024

Funding: New Zealand Winegrowers