Fault and taint remediation strategies and technologies – smoke taint background study
During the 2010 and 2011 vintages, a survey was conducted of the baseline concentrations of volatile phenols and phenolic glycosides in grapes with no history of smoke exposure. The results of this study were used to develop a ‘traffic light’ smoke taint interpretation system, which is based on statistical analysis of the baseline data. The ‘traffic light’ system has greatly improved the helpdesk’s ability to determine whether grapes have been exposed to smoke and provide advice to stakeholders. However, the 2010/2011 baseline data is limited to five varieties (Cabernet Sauvignon, Shiraz, Pinot Noir, Chardonnay and Riesling) and experience from using the ‘traffic light’ system has shown that baseline levels of smoke taint compounds for one variety cannot be applied to another. This makes interpretation of smoke taint analysis for other varieties challenging and means that it can be difficult for help-desk staff to provide producers with the information they need to make harvesting decisions. During meetings held between the AWRI and a number of industry stakeholders to identify RD&E priorities in smoke taint, there was unanimous agreement that the ‘traffic light’ system should be expanded. Accordingly, the AWRI has commenced another baseline study to expand the current ‘traffic light’ system database to include five more varieties.
2016 baseline study
During vintage 2016, more than 160 grape samples of the varieties Sauvignon Blanc, Pinot Gris, Semillon, Merlot and Grenache were collected for the AWRI by industry. These varieties were chosen based on consultation with industry stakeholders and the area of plantings in Australia. In the second half of 2016, the frozen grape samples will be thawed and analysed for the concentration of volatile phenols and phenolic glycosides. Small-lot fermentations will be conducted and the resulting wines will also be analysed. The new data obtained from the 2016 samples will be subjected to statistical analysis and the ‘traffic light’ database will be updated with the data for the five new varieties in time for the 2017 vintage.