Issue link: http://winesandvines.uberflip.com/i/63937
WINEMAKING cork to synthetics or screwcaps. This demonstrates that the variation caused by faulty closures is significant enough to be sensed by consumers—and worth eradicating even if this eradication comes at a cost. If variation in SO2 levels didn't translate into sensory changes that could be picked up by consumers, then there is less incentive to deal with it. What this study shows is that the varia- tion in technical parameters is very large (with 77% of bottles failing the quality standard selected in this study), although this variation doesn't fully translate through to the sensory properties as picked up by the panel. This is to be expected, because it is hard to get precise data when humans are involved. What would be helpful to know is how the specific variation in, for example, free SO2 level where the average consumer would notice a sensory deviation if they were presented with multiple bottles of the same wine to taste. "While there may be a question over what is acceptable bottle variation," Gab- bani says, "I felt that it was reasonable to take the most consistent wines and bench- mark everything against them. On that basis, over 70% of the bottles were outside tolerance levels. Surely that is significant." The importance of the study, Gabbani levels translates to sensory proper- ties in the wine—or how the bottles that failed the technical analysis fared in the sensory analysis. Indeed, it would make sense to have a technical quality standard that reflected projected changes in sensory properties. Here, the technical standard allowed bottles to differ by 10% from the mean and no more. Is this too strict? In an ideal world we'd like to set this at the Vinters_GrapePress_Jun09.qxp 5/8/09 11:47 AM Page 1 BUY YOUR NEXT GRAPE PRESS MEMBRANE FROM A COMPANY THAT KNOWS PRESSES! says, is it points out that there's a lot of room for improvement in the wine industry when it comes to product consistency. "Overall, the report has got to be 'must try harder,'" he says. "Coca-Cola, Budweiser, Tropicana and other drinks brands invest in ensuring that consistency is an inherent part of their brand message. Why doesn't the wine industry?" He also thinks that consistency is one of the keys to strong market performance. "When many New World wines first came to the UK, they were successful almost entirely because you knew what you were getting when you bought a bottle of Turn- ing Leaf or Jacob's Creek. There was a step change in consistency—and oddly enough, there was a boom at the same time." The scope of the DIAM study is impres- sive, and the results striking, demonstrat- ing that bottle variation is a real issue. It also is an indication of the complexity and expense of doing good, scientifically reputable trials. Many questions remain unanswered, even after a trial of this scope. As already mentioned, it would be great to link the sensory analysis directly to techni- cal data. And a bigger trial would allow a more thorough analysis regarding the ef- fect of closure type on the variation that is observed: It would be expected that some closures are more consistent than others in terms of their real-world performance. sources of variation It would be useful to get a handle on where this variation comes from. The chief culprits likely are closure type and bottling conditions. Other investigations (such as the work done by synthetic closure manufacturer Nomacorc using its Nomasense luminescent oxygen probes) have highlighted the lack of consistent oxygen pick-up in wine industry bottling, and this will have a significant effect on wine shelf life. Typically, when the free SO2 level drops below 10mg/liter, white wines will begin to show signs of oxida- tion (although this is a generalization, not FRENCH AND AMERICAN OAK for fine wine Vintners Supply Company has been supplying replacement wine press membranes since 1996. Our membranes are manufactured in Germany by technicians with years of experience in manufacturing and servicing grape presses.We stock replacement membranes for most any make and model of grape press. Please contact us for a no obligation quote. If we do not have it, we can make it! CALL 877-542-1158 TO ASK US ABOUT OUR NEW TOAST BLENDS Toll Free: 800-366-6809 • Fax: 707-584-7955 E-mail: membranes@vintnerssupply.com www.vintnerssupply.com St. Helena, CA 94574-0153 P.O. Box 153 60 Wines & Vines MAY 2012