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86 p r a c t i c a l w i n e r y & v i n e ya r d M ay 2 0 1 4 w i n e M a K i n g iticulture MEMBERS SAVE! Member registration fees are up to 50% lower 65th ASEV National Conference & 39th ASEV Eastern Section Annual Meeting June 23–27, 2014 | Hyatt Regency Austin | Austin, Texas USA S p E c i A l E V E n T S • Merit Award Presentation — Dr. Linda Bisson, nia, Davis • T d & W our • W • Winemaking for Challenging Environments • Research Reports • • W Visit our website for updates on the 2014 program. www.asev.org l 530-753-3142 65 n a t i o n a l c o n f e r e n c e s i x t y f i f t h s c i e n c e a p l a t f o r m f o r p r o g r e s s The concentrations of volatile sulfur compounds in the wines were analysed over a 12-month period. At bottling, the wines contained oxygen at around the recommended level of 1 mg/L (Chardon- nay 1.11 ± 0.34 mg/L; Shiraz 1.43 ± 0.35 mg/L). After four months of anaerobic storage, the dissolved oxygen (DO) of both Char- donnay and Shiraz samples decreased to 0 µg/L. Significant changes in volatile sulfur compounds were observed during the 12-month period, with the Chardon- nay samples showing increases in H 2 S and DMS, and the Shiraz samples show- ing increases in H 2 S and MeSH. It is not just copper The most remarkable results of this study were the effects observed due to metals that have not previously been considered in the context of volatile sulfur com- pounds in wine (Mn, Zn and Al) and the interactions between the five metals. If the Chardonnay and Shiraz samples are con- sidered together, only seven of the 31 metal treatments significantly affected the evolution of H 2 S in both wines: Cu, Fe, Zn, Al, Cu*Fe, † Cu*Mn*Al and Cu*Zn*Al. ( † The notation 'Cu*Fe' indicates a treat- ment of Cu and Fe in combination.) Three of the metal treatments (Zn, Mn*Zn*Al and Cu*Fe*Mn*Zn) that were associated with the largest increases in H 2 S concentrations in the Chardonnay samples at month 10 are shown in Figure 1. Using H 2 S levels in Chardonnay with different copper dosing levels Added Cu (mg/L) H 2 S Unfined H 2 S Fined H 2 S 3.00 2.50 2.00 1.50 1.00 0.50 0.00 0 0.2 0.5 0.75 1.5 Figure 2. The relationship between copper dose and H 2 S formation after six months for a bentonite-fined and unfined Chardonnay wine bottled under commercial conditions. Figure 3. The relationship between the copper:iron ratio and H 2 S forma- tion after six months for bentonite-fined and unfined Chardonnay wine. The blue diamonds represent the unfined wines (0.2 mg/L iron); the yel- low diamonds represent the fined wines (0.5 mg/L iron), and the two red squares are the wines with the extreme copper dose (1.5 mg/L).