Fall 2009 Newsletter
Case Study: Off Odor of Wine
A winery contacted Chemir after noticing an off-odor in their bottled wine. To help the winery determine the source of the problem, we simultaneously captured a profile of the wine’s volatile components and carried out research of common wine quality issues. After several common issues were dismissed by the analytical results, we found another cause of the off-odor from our analysis that allowed the winery to revise their manufacturing and handling methods to prevent reoccurrence.
To establish benchmarks, we compared two samples of wine with the off-odor to samples of “good” wine from the previous year. Gas Chromatography/Mass Spectrometry with Solid Phase Micro Extraction (SPME) sampling (See chart below.) allowed us to separate over 100 compounds. Compound identities and their relative amounts were compared to sniff out the off-odor compound.
Initially, the SPME GC-MS results and extensive literature research on the known chemical causes of off-odors in wine led us to eliminate many likely suspects, such as pesticides and pesticide degradation contamination, sulfur compounds, industrial solvents, and brominated anisole due to “cork taint”. Finally, with persistent concentration to the compounds present at lower levels, we uncovered abnormally high levels of two furan compounds, 2-furanmethanol and 2-furaldehyde, in the off-odor wine not present in the “good” wine. To give the winery meaningful results from which they could take action, we advised them that the high furan levels may have resulted from microbial action or high temperature exposure, leading them to design changes to their manufacturing and handling processes.
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