Hugh Schuitemaker, Murray Pioneer
A senior Riverland winemaker says grapes currently being harvested for vintage are vulnerable to damage from a heatwave being experienced across the region.
Current forecasted temperatures for the Riverland are set to remain above at least 37C until Tuesday, with a high of 41 set for tomorrow.
Renmark-based Angove Family Winemakers chief winemaker Tony Ingle said the excessive heat could cause grapes on vines to appear ready for harvest without the necessary character development for quality wine.
“We’ll see a super-charged ripening, and we’ll get dehydration,” Mr Ingle said.
“Dehydration is not necessarily the same as ripening. We’ll lose a lot of acid, but we won’t see a lot of the phenolic flavours ripen.
“There’s the potential that we’ll pick (the grapes) at a certain baumé – or sweetness – but the fruit isn’t quite ready yet.
“We’ve got to be really careful, for quality instances, that we don’t pick too early, even though the sugar numbers are correct.”
Mr Ingle said higher temperatures in the evening could also impede the quality of wines made in the 2025 vintage.
“Usually it’s 10C to 15C at night, but for the next couple weeks it’s going to be 22C and 23C,” he said.
“We’re very lucky that we’ve picked (nearly) all our whites. Those who haven’t picked their whites yet will be seeing a lot more issues.
“Winemaking is all about control, and the higher the temperature is, the quicker chemical reactions happen. We want to keep those temperatures down to slow chemical reactions, and one of those would be oxidisation and spoilage.
“The lower the temperature the better.” Chaffey MP Tim Whetstone said any loss of grapes due to the heat would add further financial pressure to Riverland growers.
“This season has again thrown a range of challenges at growers, from commodity prices to frost and now extreme heat,” Mr Whetstone said.
“The excessive heat will reduce yield, further compounding the challenges of being a wine grape grower in the Riverland this vintage.”
Mr Ingle said regular sampling of grapes and and communication with their contracted winery, needed to be a priority for local growers.
“There will be a lower crop this year, and we’re seeing that across the board,” he said.
“There is a reduction in yield right across the region. In fact I would say the whole of South Australia is low, so what fruit we do bring in really needs to be correct.
“It’s really important we’re out in the vineyar… tasting things.
“(Growers) need to be out there sampling and making sure they’ve got the right numbers into the winery. Make sure you’ve got up-to-date baumés in the winery, tell them what you’ve got and make sure you sample twice a week.”
This article appeared in Murray Pioneer, 5 February 2025.
