Grape expectations: winemakers preserve quality with late pruning

By: Genevieve Gannon
28 November, 2012

Australian winemakers can trick their grapes into maturing later in a bid to counteract the effects of climate change, research shows.

Over the past 25 years, the harvest date for Australian wines has come forward almost one day a year, agricultural scientist Professor Snow Barlow says.

Pruning grapevines a month later is one of the tactics being employed by a major Australian winemaker to delay the growth of grapes, so they mature like they did before the seasons started to change.

National viticulturist for the Treasury Wine Estates Paul Petrie will this week present his findings on the delayed pruning of grapevines at the Climate Change Research Strategy for Primary Industries (CCRSPI) conference in Melbourne.

Prof Barlow, the executive director of CCRSPI, said Petrie had had some success in delaying the growth of the wine grapes by delaying the pruning of the vines - which is a key part of the grape growing cycle.

"We've got climate change pressuring the season one way, if we don't prune them until very late we'll push them the other way and maybe we'll end up in the same place as we were," Prof Barlow told reporters.

Prof Barlow, who operates vineyards in the Strathbogie Ranges in north eastern Victoria, said changing weather patterns can affect the quality of wine produced.

"Wine is different from wheat and milk. It's about quality rather than quantity," Prof Barlow said.

"If you have (a grapevine) in the wrong place it might die.

"It might not express itself fully, in that it might not produce that robust wine that you want to produce."

He said this can damage a brand that relies upon producing a consistent flavour year after year.

Climate change is affecting not only the flavour of the grape, but also the capacity of wineries to effectively utilise their infrastructure.

The CCRSPI conference will hear from wine makers and scientists who have turned their minds to the challenge of sustaining a wine industry in the face of rising temperatures.

Prof Barlow said most commercial wineries would expect to use their fermentation tanks three times a year, but because of the shift in seasons growers are experiencing a compression of vintage.

"All the grapes start coming in together," he said.

"It causes some scheduling problems and if it continues they may have to buy more tanks. But that's expensive."

But it's not all bad news.

"People are producing new sorts of wines more in line with the climate conditions they're facing," Prof Barlow said.

"So we can look forward to some different wines, some of which we might like."

Source: AAP