Are increasing temperatures responsible for making wines less healthy because of high alcohol content? I’m just back from Australia, where I was honored to present a talk at the 2019 Wine Media Conference in Hunter Valley, and I learned a lot about the changing conditions that winemakers there and around the world are dealing with. My subject was Australia’s winemaking doctors, from Drs. Christopher Penfold and Henry Lindeman to current vigneron medicos such as Philip Norrie, who are collectively responsible for most Australian wine production throughout its history. But Penfold’s and Lindeman’s low alcohol wines of the 19th century would be unrecognizable now.
High alcohol wine makes health studies problematic
A perk of these conferences is the opportunity to taste a lot of really outstanding wines. One that really blew me over (name withheld) turned out to have an alcohol content of 16.7%, and that got me thinking. Blame Robert Parker, climate change, or evolving consumer tastes, but the predominance of high alcohol wines (usually defined as >14.5%) is a potential health issue. At restaurants in Sydney, I noticed that wine glasses were marked to indicate the standard pour of 150 ml (5 ounces), which is the amount that health studies traditionally use. But without accounting for escalating alcohol levels, health studies from only a decade or two ago may be meaningless.
Barossa Valley Shiraz is famously the face of high octane Australian wines, but I was surprised to learn that Hunter Valley is actually hotter, behind only the smaller Riverina, Riverland and Rutherglen regions. Heat translates to high sugars and therefore alcohol, but the Hunter Valley style favors a leaner and more acidic character; they use the word “textural” a lot when describing their wines. One way winegrowers there are coping with changing conditions is by application of “sunscreen,” a practice I hadn’t heard of before. It’s an emulsion of fine clay sprayed on the plants when there is too much sun. (This was originally developed by apple farmers in order to prevent sunscald browning and promote better color development.)
Climate change is not entirely to blame
Of course it isn’t realistic to expect winemakers to dial alcohol content back to the 11-12% range of olden times, or for consumers to buy them. People like the big new wines. And just about every country that exports wine is already fudging the numbers to suggest that the alcohol content in their wines is lower than labeled, according to an analysis done by the Liquor Control Board of Ontario, Canada a few years ago. (The worst offenders were Argentina, Chile and the United States BTW.) True alcohol content averaged about a half percent more than stated, but their data also provided an opportunity to track changes over time. A review by the American Association of Wine Economists found that alcohol levels in imported wines rose from an average of about 12.6% in 1992 to over 13.6% by 2006; they are almost certainly higher across the board today, though reliable numbers are hard to track down. Interestingly, the AAWE researchers then looked at the heat index in the respective growing regions, and concluded that climate change was only partly to blame for higher alcohol. The trend is partly driven by consumer preference (and ratings), and you can’t blame the wineries for making wines that people want to buy. That leaves us wine lovers in a position of influence, and I would argue along with that comes a measure of responsibility, if the notion of wine as a healthy thing is to be sustained.