Sometimes you need a study to affirm what you suspect. Such is the case with a recent paper that shows wine labels to understate actual alcohol by at least 0.3 percentage points, on average. And increasing alcohol levels have little to do with climate change in aggregate; instead, the researchers suggest, it results from winemaker choice.
The study, whose lead author Julian Alston of UC Davis, examined data from 129,123 wine samples. Although the US federal authorities perform scant testing of wines in the marketplace, the Liquor Control Board of Ontario (LCBO) runs each bottle of wine through a lab test before it is allowed to appear in the market (I wonder who brings home the leftover Petrus each year?). The Alston study uses a large portion this LCBO data from 1992-2009 to compare the alcohol level stated on the label versus what actually appears in the bottle and puts to shame my data set of 84 bottles for my own study in Wine & Spirits last year. The working paper was published by the American Association of Wine Economists.
Using climate data, Alston et al. find that the heat index in most wine countries grew less than rise in alcohol levels–to explain a rise of wine percentage point in the alcohol of a wine, a 20 degree Fahrenheit increase would need to been seen, which obviously didn’t happen in the time frame. Thus, they conclude not all that surprisingly, that their findings “lead us to think that the rise in alcohol content of wine is primarily man-made.” This is a particularly interesting empirical finding since it categorically refutes the claims of some winemakers who point to global warming to explain why the level of alcohol has risen in their own wines over the past decade or so.
Turning to the discrepancy between what’s on the label and what’s in the bottle, the study finds 57% of the nearly 100,000 samples to understate the alcohol level with the worst offending category being New World red wine (about .45 percentage points). They lay the blame for this at the door of winemakers and vintners:
We speculate that commercial wineries for the most part have relatively precise knowledge of the alcohol content of the wines they produce and that the substantial average errors that we observe are not made unconsciously. This speculation is based in part on informal discussions with some winemakers who have admitted that they deliberately chose to understate the alcohol content on a wine label, within the range of error permitted by the law, because they believed that it would be advantageous for marketing the wine to do so.
They suggest that consumers “will happily pay a premium” for the riper, more intense flavors that come from the grapes hanging longer in the vine but that consumers don’t want the alcohol that also comes with it, which leads to the cause of widespread label understatement.
What do you think about that assertion?
The authors conclude, “What remains to be resolved is why consumers choose to pay winemakers to lie to them.” Funny, yes, but consumers can be forgiven for trusting what is on the label as being accurate. The blame for the discrepancy, in my view, ultimately rests with regulatory authorities who either tolerate the “lies” or fail to monitor deviations from stated levels.
It’s a rich study and definitely one worth geeking out on while sipping a wine that has a 57% chance of misstating the alcohol level. Take a look:
“Splendide Mendax: False Label Claims about High and Rising Alcohol Content of Wine” Working Paper #82, AAWE [pdf]