Growers in South Australia have been forced to harvest early as the current heatwave hits the vineyards.

Reports estimate that temperatures of 46C and above could see some areas lose up to 70% of their crop.

McLaren Vale and Langhorne Creek have been worst hit with the Barossa Valley and Coonawarra also affected.

Sam Connew, winemaker at Wirra Wirra in McLaren Vale, said: ‘After a week of 40 plus temperatures we are seeing the vineyards fall apart. I am worried about the reds. We are a good three to four weeks away from decent flavours and Shiraz is suffering badly in some vineyards, as well as any exposed bunches just turning to raisins.’

She added, ‘Some people are picking already, but I am not sure that that is wise. I seriously doubt whether many vineyards would be physiologically ripe.’

Major producer Australian Vintage (AV) makes wine throughout Australia and reports Coonawarra and the Limestone Coast will also be down 25-30%.

Adelaide Hills has avoided major problems. Neil McGuigan, head of production at AV said: ‘We will finish harvesting our whites from the Barossa tonight and we will be below expectation by 40%. Reds will start to be harvested next week but even before the heat, we believed it was going to be a light crop anyway. Who knows where we will end up? If whites are down 40% you can expect reds to be down further.’

The Winegrape Council of South Australia has said it will be several weeks before the full impact of the heatwave can be assessed.

Written by Rebecca Gibb