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68 p r a c t i c a l w i n e r y & v i n e ya r d d e c e M B e r 2 0 1 4 W I N E M A K I N G to see the influence of these sulfur com- pounds on the aroma and flavor attributes rated through expert sensory panels, even though they are all at or above the sensory detection threshold. In red wines, these odorous sulfur com- pounds can be masked at these levels, but there is still a risk that they may increase over time and start to significantly affect the aroma and flavor of the wine. It may also be the case that soon after wine is poured, the compounds interact very rap- idly with oxygen in the air, reducing their impact in sensory trials. Sensory data from the red wine closure trial were analysed using principal com- ponent analysis (PCA). The PCA plot in Figure 10 shows that the aroma and flavor attributes of red wine can be strongly in- fluenced by closure type. Screw caps Alterna ves Natural Cork Technical Cork 3.0 2.5 2.0 1.5 1.0 0.5 0 0 6 12 18 Months 24 30 36 H 2 S concentra on (µg/L) Figure 8. H 2 S concentration changes in white wine under different closure types over 36 months. Error bars indicate minimum and maximum values for each closure type (detection threshold of 1 μg/L shown by dotted line). Screw-caps Alterna ves Natural Cork Technical Cork 12.0 10.0 8.0 6.0 4.0 2.0 0.0 0 6 12 18 Months 24 30 MeSH concentra on (µg/L) Figure 9. MeSH concentration changes in white wine under different closure types over 36 months. Error bars indicate minimum and maximum values for each closure type (detection threshold of 1.5 µg/L shown by dotted line). Bitter Brown color Dark fruit Cooked fruit Port/ Bruised apple OTR DMS Color density Hue Opacity Medicinal/ Pine Fruit AT Screwcap Screwcap Screwcap Screwcap Screwcap Methanethiol Alternative Alternative Alternative Natural cork Technical cork Technical cork Technical cork Technical cork Natural cork Free SO 2 H 2 S Total SO 2 PC2 (23.65 %) PC1 (42.69 %) Figure 10: Principal component analysis (PCA) plot showing relationship between aroma, flavor and chemical attributes for red wine under different closures after 24 months of storage. 1164 Lee Street, White Rock, B.C. V4B 4P4 Canada Phone: (604) 538-2713 Fax: (604) 538-4517 www.idlconsulting.com IDL Process Solutions Inc. Process & Product Development Alcoholic & Non Alcoholic Beverage Industry Equipment Sales Iván D. Lessner ■ R. WAGNER: Rapid SO 2 , TA ■ ERBSLOEH: Fining & Treatment Agents, Yeasts, Enzymes, CelluFluxx (D.E. Replacement) ■ TRUST: Quality Hungarian Oak Barrels & Chips ■ EMD: Reflectoquant Analyzer & Kits IDL_Dir11 11/18/10 4:21 PM Page 1 Call your Associate today for competitive financing! Fixed and adjustable rate mortgage loans Dana Cummings Kennewick, WA, 509-783-9191 Scott Gay Napa, CA, 707-477-2425 Josh Gervase Escalon, CA, 209-608-0321 Bill Sciacqua Fresno, CA, 559-470-6448 Brendan Feder Visalia, CA, 559-312-4437 Jonathan W. Holbrook Food & Agribusiness, 559-470-6444 Agricultural Investments Your lender of choice for agricultural capital. © 2014 METLIFE, INC. © '14 PNTS www.metlife.com/ag