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WINEMAKING Study Examines Bottle Variation Lab tests and sensory panels analyze 30 leading brands for SO2 By Jamie Goode Wine Number Free SO2 Highlights • Closure manufacturer DIAM commis- sioned the first major study to address the vexed issue of bottle variation in the wine industry. • It looked at the bottle-to-bottle varia- tion in 30 of the best-selling wines in the United States, with 18 bottles of each wine subjected to chemical and sensory analysis. • The findings from lab analysis were that only 23% of bottles passed a speculative quality-control standard. Sensory findings were more difficult to interpret. bottle variation. It could rightly be called the dirty secret of the industry. When a consumer buys a particular bottle of wine on repeated occasions, how consistent is that experience? There's a strong suspicion in the industry—for example from studies that have looked at oxygen pick-up during bottling and clo- sure trials—that they might be experienc- ing a different wine each time. But while we know that bottle variation exists, no one has really tried to quantify the level of bottle variation in a rigorous manner. There are numerous possible causes of bottle variation. These include lack of quality control at bottling, variability in closure performance, inconsistent glass bottles, temperature changes during shipping or transport and light or heat exposure while the wine is sitting on the B 56 Wines & Vines MAY 2012 40 Measurements by Wine Strip plot of SO2 data shows values for bottles plotted vertically for each wine. Red plus signs (+) and green whiskers are the sample mean and its 95% confidence interval. 30 and TCA 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Wine Number Wine Number ack in November 2009, 14 wine industry leaders from a range of disciplines met to discuss a major study on what should be an impor- tant topic for the wine trade: retail shelf. But despite these sources of variation, no quality control standard ex- ists for wine. beginning the study The study in question was funded by wine closure manufacturer DIAM Bouchage (makers of the DIAM technical cork) and was driven by DIAM's sales direc- tor at the time, Dean Banister, along with James Gabbani of CUBE Communica- tions, based in Wimbledon, England. Back in 2001, Gabbani was responsible for organizing a large closure trial in the UK, providing him with experience conducting large-scale studies of this kind. DIAM's focus, surprisingly, was not on closure- related variation—although this is clearly a topic of great interest to the company. Instead, DIAM chose to focus purely on the level of bottle variation that might be experienced by consumers purchasing the best-selling wines in the United States, ir- respective of the closure used to seal them. "Bottle variation is the wine indus- try's elephant in the room," Gabbani says. "Producers spend billions globally trying to recruit new customers, and it's no big secret that keeping a customer is cheaper than recruiting a new one. Con- sumers rarely understand that a wine is faulty and frequently just put it down to the wine being just 'not as good as it used to be.' The difficulty is that the producer will never hear that, and there- fore can't do anything about it. They just lose the customer. Bottle variation is a hidden cost." While producers might see tackling bottle variation as an added expense at a time when margins are already paper thin, a study like this has the potential to show that tackling it could actually be a cost- saving decision. ulterior motive for study Gabbani explained why he was motivated to instigate this topic. "I'd been given data suggesting that over 75% of the U.S. wine industry was using natural cork, with only 25% accounting for everything else," he explains. "Given that other parts of Free SO2 0 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 Free SO2 mg/liter 20 30 40 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 0 50 TotalSO2