Bottle Variation: Fly in the Soup

Wine critics base their evaluation and scoring of wines usually on the sampling of a single bottle. Occasionally a flawed or “off” bottle is met with, and a second bottle is opened, but the majority of wines are judged on one bottle. I believe bottle variation can affect the judging of wines creating a “fly in the soup.”

A major study funded by wine closure manufacturer, DIAM Bouchage, the producers of the DIAM technical cork, focused entirely on bottle variation that consumers in the United States might meet with when buying leading brands of wines. John Gabbani of CUBE Communications helped organize the study. He said, “Bottle variation is the wine industry’s elephant in the room.”

The study was reported in the latest June 2012 issue of Wines & Vines (but unpublished elsewhere) and included thirty of the best-selling wines in the United States (the top ten sellers by volume in each of three price categories). Eighteen bottles of each wine were bought at retail stores in the San Francisco area, critically examined by technical and sensory analysis, with the results tabulated by a professional statistician. The technical testing screened for TCA and levels of total and free sulfur dioxide (sulfur dioxide is a good indicator of bottle variation since the levels of sulfur dioxide will reflect variations in bottling, closure inconsistencies, and exposure to heat). Sensory testing was performed by judges who rate the quality of the wines based on fruit, floral, earth, oxidation and TCA criteria.

The study revealed that only 23% of the sampled wines met the stringent technical quality standard meaning 77% of the wines failed. Most of the wines passed the total sulfur dioxide consistency test, but only 60% passed the test for free sulfur dioxide. The TCA defect rate was high, with only 43% of the wines passing the test. The sensory testing indicated that bottle variation was picked up less often by the judging panel, and only occurred in 12% of the wines using all measured criteria.

Using the most consistent wines as benchmarks, the study concluded that over 70% of the bottles exceeded tolerance levels. The wines bottled with technical corks and screw caps were more consistent than natural cork and synthetic closures.

The London Wine Fair: 02inWines (May 29, 2011) featured a bottle-to-bottle variation panel discussion led by noted wine writer, Jamie Goode. The panelists emphasized the importance of oxygen management in insuring consistency of bottles. Glass quality, choice of closure and application of closure all influence bottled wine consistency. Wine transportation and storage are factors as well, the panel said, with excess cold or heat having a significant detrimental effect on wine quality.

The challenge of bottle variation is compounded with Pinot Noir, since it tends to come and go like a chameleon in the bottle, particularly with aromatics. I often receive two bottles of the same wine for review. Over the past few months, I have opened two bottles of the same wine on occasion and compared them. Surprisingly, I noticed enough bottle variation in some wines to significantly impact my quality judgment. In some cases, the bottle variation is vary subtle, but enough to influence the final rating. For this reason, and from this point forward, if I have the slightest suspicion that a wine is not pristine or does not represent a proper example, I will open the second bottle for comparison. If I only receive one bottle, I must base my review on that single bottle, or attempt to obtain a second bottle. This can be quite a nuisance, much like a fly in the soup, but absolutely necessary for fair wine evaluations.