A record-breaking heat wave has hit South Australia in the middle of this year's harvest, sending the grapes' sugar levels soaring and forcing winemakers to scramble to harvest their fruit. Adelaide, the city closest to Australia's major winegrowing regions, has sweltered through 15 consecutive days above 35° Celsius (95° Fahrenheit), the longest heat wave recorded in any Australian capital city. Scientists have called the event a once-in-3000-year occurrence.
"It wasn't just the number of days over 35 that concerned us, but that 12 of these were above 38 [degrees] (100.4 Fahrenheit)," said Penfolds chief winemaker Peter Gago. Throughout South Australia, cellar workers were pulling 12-hour-plus shifts in temperatures between 45 and 48 degrees Celsius (113 to 118 Fahrenheit). "We had everything going at full pace, with all the fermentors full and fruit still coming in," Gago said.
Barossa Valley winemaker and grower Wayne Dutschke of Dutschke Wines, reported a crop of Shiraz coming in at 25 Baumé (45 Brix), almost double the usual sugar ripeness of Barossa Shiraz. "The heat wave has produced crazy numbers!" he said.
And not only from the valley floor. Henschke winemaker Stephen Henschke, who makes his Hill of Grace Shiraz from the cooler Eden Valley region, said, "We've had two weeks of extraordinary heat--it's been murder. The vines aren't holding up very well at all. There are going be a lot of raisiny, jammy reds, but this is just par for the course in a hot vintage."
The heat couldn't have come at a worse time, so far as many of the country's winemakers are concerned. "We've had no rain since mid-December, which has put added stress on the vines," Henschke pointed out, so few growers have sufficient water reserves to hydrate their vines. "And even with water, there's a limit as to how long vines can stand up under those conditions," he said.
Henschke was optimistic about his top wines, however, pointing out that his older, deeper-rooted vines, including those in the Hill of Grace vineyard, have stood up to the conditions well.
Some growers, however, were able to beat the heat entirely. The heat followed an ideal, cool, even-ripening period, so many producers had picked their fruit before the danger period. But they just happened to get lucky. "The biggest problem was that none of the heat was forecast, so we had no chance to rush our fruit in before it hit," Gago said. "No one knew that we would have two weeks like this."
Gago said that Penfolds' premium wines, including Grange, have escaped largely unscathed. "We've been pretty lucky," he said. "Our best Shiraz from the Barossa always comes in early, and it's looking really good this year."
Others have been less fortunate. "You couldn't get a slot on the crusher, couldn't get trucks or harvesters," said Adelaide Hills winemaker Mike Press. "And even when you could, a lot of growers had their fruit rejected because the [sugar levels] were too high."
Managing tough or varying conditions, however, is all part of winemaking, Gago pointed out.
"I can only think of two 'normal' vintages in the past decade," he said. "Weather patterns are all about cycles and oscillation, and it's hard to make a call when you're in the middle of it. You might think a vintage is extreme—but then another one comes along and the record is broken again."
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