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WINEMAKING E. wil k es location of those trees near Pulp vs. Skin vines provided a more likely Skin explanation. 1.31 ng/berry The AWRI also compared red and white wines to see whether there was a clear difference between varieties. A survey of 190 commercially Pulp available Australian wines 0.36 ng/berry found eucalyptol (or 1,8-cinConcentrations of 1,8-cineole in eole) in significant amounts berries confirmed the existence in red wine varieties only. The of some airborne transmission. survey led to the daily monitoring of two commercial Shiraz ferments from two different winegrowing regions in South Australia throughout fermentation, revealing a continuous increase in the concentration of 1,8-cineole during fermentation that stopped once the wine was drained from the skins. This indicated that the compound was extracted from the grape skins and/or material other than grapes, commonly known as MOG. How the aroma compound was transferred to grape skins and what is the role of MOG were questions requiring further investigation. In parallel, consumer studies were carried out by the AWRI sensory team,4 and they found that overall, participants (104 people) had a slight preference for a wine spiked with 4 micrograms per liter (μg/L) and 30μg/L of 1,8-cineole compared with an unspiked one, with a sizable cluster of consumers (38%) strongly preferring the wine spiked with 30μg/L of 1,8-cineole. Getting the right balance for 1/8/09 10:59 AM careful TonnellerieBoutes_Feb09.qxp consumers requires Page 1 management, and to make that happen, winemakers needed to know where the compound 1,8-cineole was coming from. They also needed to know how to control its concentration in wine. To find out more, the AWRI carried out a detailed study over three vintages to investigate the relationship between grape composition and the proximity of vines to eucalyptus trees. The impact of grape leaves, grape stems and leaves from nearby eucalyptus trees also were included in the investigation. The results of this work provided important information that has the potential to change the way winemakers understand and manage "eucalypt" characters in red wines. Investigative tools Key ingredients for the AWRI study were samples of wine, grapes, grape stems and leaves—as well as samples of eucalyptus leaves. Wine samples from Great Southern in Western Australia, Yarra Valley in Victoria and Coonawarra in South Australia were supplied by producers. Healthy Shiraz grapes were hand-harvested from the Padthaway region of South Australia one day prior to commercial harvest. Samples were taken over three vintages (2008, 2009 and 2011), in the same locations each year. To assess the impact of proximity to eucalyptus trees, three samples of grapes were taken from three separate locations within four different rows of the vineyard (providing 36 samples in all for each vintage). The rows were located at different distances from eucalyptus trees: the first row within about five meters, the furthest around 125 meters from the trees. Grape leaves also were collected from the same spots in 2009 and 2011, and eucalyptus leaves also were taken from the grapevine canopy of the first row in 2011 for analysis and addition to ferment treatments. Flavor compound traps (consisting of poly- Win es & Vin es F EB RUA RY 20 13 53