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The study was reported in the latest June 2012 issue of Wines & Vines (but unpublished elsewhere) and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.