The business of very fine wine happens in a rarefied atmosphere, so it’s ironic that one of the most highly discussed issues concerning wines’ cellar worthiness concerns oxygen—specifically, premature oxidation.
Wine aging is essentially a slow process of oxidation, but the thought that some of the world’s most expensive and collectible wines might age prematurely is worrisome. Collectors and passionate tasters want to lay the wines down for decades, whether for enjoyment or resale value, and rightly flinch at the prospect of their investment being rendered worthless.
The Pox Plague
The issue of “premox” (or even “pox,” its other nickname) first came to the fore at the turn of this century, when bottles of highly valued white Burgundies from the mid-1990s showed up dead on opening. They exhibited dark color, with their fruit aromas gone and none of the zip and freshness that Chardonnays from Bourgogne are known for—even though they were barely a few years old. The problem generated a lot of research and discussion, and although no single clear and definite cause has been identified, certain issues related to bottling, as well as certain aspects vineyard management, have been fingered as likely culprits.
Organizations like the Bureau Interprofessionnel des Vins de Bourgogne (BIVB) have provided producers with guidelines to help counter the problem, which seems to be lessening in the region. In an interview with Vitisphère (subscription only), BIVB technical commission vice president Géraud-Pierre Aussendou reported a much lower occurrence thanks to greater awareness and changes in winemaking choices, notably picking earlier to preserve acidity.
The Red Menace
Still, similar questions have been raised about white wines from regions like California and Australia. And in the last few months, concerns about premature oxidation have been revived in recent articles stating that the problem could happen in high-end red wines as well. Reporting on a study from Bordeaux researcher Denis Dubourdieu and his colleagues Valérie Lavigne and Alexandre Pons, Jane Anson wrote in Decanter that the lack of stamina of high-end wines is an impending wine crisis:
“There were plenty of rumblings about this at a recent ten-years-on tasting of Bordeaux classed growths from the 2003 vintage. Even among the biggest names there were bottles that were showing tired fruit, flabby structure, and were generally past their prime; all signs of oxidative destruction that is not expected at such an early stage in the life cycle of fine red wine.”
The likely culprits, as pointed out by Douburdieu, are overripe grapes with high pH, excessive contact with oxygen at an early stage in winemaking, high amounts of new oak, and lower SO2 levels. While all of these choices are made with good intentions—and for pleasing certain influential critics who liked the bigger, bolder, friendlier style—this combination can potentially reduce the wines’ resistance to oxygen and thus their capacity for aging.
Of course, as Anson recognizes in her article, the 2003 Bordeaux vintage is a bit of an extreme example. A summer of excessive heat, unseen before or since, caused sugars to rise and acids to drop at an unprecedented rate there and in many other European wine growing regions. Looking for both ripeness and balance was a difficult challenge that year, and no one expected such a sun-baked vintage to provide the best aging potential, even early on. In that sense, is it really so surprising that wines made in such extreme and unusual conditions are showing a bit of fatigue at 10 (and now 12) years old?
Dubourdieu and his colleagues, however, insist that if subjected to certain practices, wines from all hot and ripe vintages (like 2009, for example) could be at risk. Many issues are likely at play, but in wines with higher pH—especially nearing a pH of 4—SO2’s protective capacity against oxidation is greatly diminished. This in turn accelerates the chain reactions that lead to stewed fruit and dried fruit characters, as well as a loss of color and other characteristics of aged wines.
Random vs. Uniform
While the question of a wine’s aging potential—and how vineyard practices and winemaking techniques may affect it—is a fascinating subject, it seems a somewhat distinct question from the original premox crisis of the mid-1990s. Those premox issues in Burgundy were characterized by the random appearance of highly-oxidized bottles within a same lot, meaning that while some bottles showed up stewed and old, others were crisp and fine. The issues raised by Dubourdieu and his colleagues, however, point to a tendency for all wines from hot vintages, or at least those made in a very ripe, low-acid style, to age faster than expected, meaning over several years rather than over a few decades.
While the two issues do have some common characteristics—in both cases, high pH is a big part of the problem, for instance—there are clearly some different mechanisms at work. In the case of white Burgundy, the question largely has to do with uniformity and homogeneity. In the case of red Bordeaux and other big, cellar worthy red wines, the issue seems to have more to do with wine growing and winemaking choices.
Regardless, both issues are certainly worth looking at carefully in terms of oxygen management, and we will return to them in further posts to address the various elements at play.