Global warming threatens wine industry

In Australia, grapes are maturing faster, which can compromise the flavor
Neil Paulett, a manufacturer of wine from the region of Clare Valley in South Australia State, stopped the car in front of a row of vines in a recent rainy afternoon. The grapes that grow here, he said, are maturing a month earlier than they used to when he opened the winery that bears his name, in the early 80.
More grapes are maturing at the same time, shortening the traditional period of harvest in two weeks, said Paulett.
Some scientists attribute these changes to the temperature increase, something which, according to the researchers, could be a threat to wine producers in the world. The grapes that ripen too early may not develop the optimal flavors, and the late harvest can lead to levels that would make the alcoholics drink unpleasant to the taste, say scientists and growers.
Some of the greatest wineries of Australia, with the help of scholars and researchers are investigating ways to reduce this impact. At stake are about 24000 jobs in the sectors of production of wine and grape crop of Australia, as well as exports valued at 2.1 billion Australian dollars ($ 1.6 billion) a year.
The Treasury Wine Estates Ltd., the second largest Australian wine by volume, according to data collected by 2015 research firm Euromonitor International, is considering pruning his vines at the end of the year, a technique that can delay the ripening.
Already the Taylors Wines, Clare Valley''s largest Winery and the 11th of Australia by volume, also performs her first experience of late ripening through pruning and can come to apply the technique to 20% of its vineyards.
The Taylors also expanded its operations in recent years, in part to render more grapes at the same time and make better use of shorter harvests. Some companies are spreading more straw between the vines to keep the soil cooled.
If the harvest period continue anticipating, wine makers will be under heavy pressure, says Andrew Pike, who runs the Pikes Clare Valley Wine with a brother. "We''re not going to get the flavors profile we''re looking for."
Data from the Treasury Wine show that, last year, Carbenet Sauvignon grapes from the vineyards in McLaren Vale, South of Adelaide, were ripe in February 4, compared with 25 in March 1993.
The anticipation of maturation has been registered worldwide, affecting some of the major wine regions and showing a constant challenge for manufacturers.
In the region of the U.S. State of Washington, higher temperatures in 2015 prompted the harvest starting "historically earlier", according to the Commission of local wine.
Other data from the Treasury Wine show that the period of ripening in the valleys of Barossa and Eden, also in South Australia, was 24 days for the Shiraz grape in 2013, up from 47 days in 1998.
"Few wineries have the capacity to ferment all their grapes at the same time," says Vladimir Jiranek, Director of the ARC Training Center for Innovative Production of wine, part of the University of Adelaide.
The grapes left on the vine long continue maturing and accumulate more sugar, the yeast into alcohol during fermentation — so more sugar means more alcohol. This isn''t just a problem for the taste, but some jurisdictions also tax more wines with higher alcoholic content.
Jiranek group researchers found that the combination of certain types of yeast that are less efficient in transforming sugar into alcohol with standard wine yeast can download the alcoholic content. The researchers want to develop new types of yeast that can lower the alcohol content even more, says Jiranek.
In the Barossa Valley, northeast of Adelaide, which is famous for its Shiraz, the Treasury Wine intends to expand the pruning practices to delay ripening, after three years of testing. For harvest this year, some branches of vines where they grow clusters of grapes were trimmed when they had two or three sheets around the second week of October 2015. The traditional period for this is the end of may or early June.
The delayed harvest method between 10 to 14 days, compared with other vineyards, and stagger the harvest so that the grapes don''t mature at once, without compromising the quality of the fruit, according to the company. "It''s a really simple technique," says Gioia Small, regional manager of sustainability of Treasury Wine. "There''s no additional cost. It''s just a matter of programming. "
There are technologies that filter the alcohol of the wine, but some say that the methods can be costly and contradict the marketing strategy of the wineries to introduce the product as being done in a natural way.
Adam Eggins, oenologist of Taylors Wines, has other advice: invest in large storage tanks, presses and other equipment. After an especially short in 2008, the company nearly doubled its capacity, he says. "I think, in the end, we spoon because we couldn''t move fast enough," says Eggins.
Currently, there are few signs that the change in harvest periods will be reversed.
Paulett, Paulett Wines, says that this year left grapes Riesling — the characteristic type of Clare Valley — early mature spend an extra week in the vineyards to develop certain flavors. In a visit to the vineyard in early September, he stopped at an old vine Cabernet grapes where a leaf had already sprouted. "It''s a little early," he said.