Vintners in two of the world's biggest wine-producing regions, California and South Africa, have been fretting lately, and not just about the global recession. At least the economy affects all grape-growing nations more or less across the board. But the problem these winemakers have is decidedly site-specific: something seems to be happening to their terroir (the geographic characteristics of their growing region) that has them terrified.
Strange flavors are not necessarily a bad thing in wines. For instance, some good Bordeaux are described as having hints of leather. But certain aromas are decidedly rank and have no business being in your beverage. Among these, I would have to say, is burnt rubber.
That's the bouquet ascribed to many South African wines by a tart-tongued British wine critic, Jane MacQuitty of The Times of London. As Barry Bearak reported in the New York Times, MacQuitty caused a stir in 2007 when she wrote that many of the reds she tasted from the country were tainted by a "peculiar, savage, burnt rubber and dirt odour." She later called several top-rated South African wines “a cruddy, stomach-heaving and palate-crippling disappointment.”
This scathing string of adjectives stung the region's winemakers, who felt the burnt rubber comments portrayed all South African wines as being, well, tarred with the same brush. Now scientists in the department of viticulture and oenology at Stellenbosch University are trying to figure out the source of the acrid aroma, and if it even exists. As molecular biologist Florian Bauer, who is heading the team, told Bearak, "We were not even sure what smell we were looking for. This research is a response to an ill-defined description in a newspaper."
The subjectivity of flavor (and the suggestibility of tasters) is another problem. André van Rensburg, the winemaker at the Vergelegen Wine Estate, said critics at tastings "talk each other into a frenzy... If one of them picks up the taste of apple, the other guy says, ‘Yes, yes, and I taste cinnamon too.’"
Meanwhile, the question vexing winemakers in California's Sonoma and Mendocino Counties is not what's affecting their terroir, but how to deal with it. The rampant Northern Californian wildfires of 2008 subjected their grapes to a significant amount of smoke, according to an article by Jon Bonné in the San Francisco Chronicle. Although white wines have been relatively unaffected by the smoke, red wines, which contain more of the compounds from the grape skins, are more likely to be affected by "smoke taint."
A smoky aroma is not necessarily a bad thing in wine. In fact, sometimes winemakers age their product in toasted barrels specifically to capture the scent. But, Bonné wrote, an ashy taste on a wine's finish "can be bitter and almost throat-scratching."
Australia, another significant wine-producing country, dealt with a similar wildfire problem in 2003. Winemakers there used reverse osmosis and other filtration techniques to remove the smoky compounds, a path being pursued in some California wineries.
Others are taking a laissez-faire approach, and allowing the smoky undertones to stay, Bonné says, as a "signature of terroir." As one winemaker told him, "Each vintage has its character and talks about the place and the year. That's a big part of honest winemaking."