(AustrianTimes) - Austria's winegrowers are warning that the extremely mild winter is threatening this year's ice wine harvest, the so-called Eisweinlese.

Ice wine is made when some of the grapes are left on the vine after the harvest in autumn and are only plucked after the first freeze. The extreme cold means that much of the water in the grape is removed giving an extremely sugar rich mixture when the grapes are pressed and a very desert wine.

But the failure of the cold weather to arrive means that unless this changes in the next fortnight or so, the grapes will start to rot, which means there will be no ice wine this year.

Eiswein accounts for between 1% and 3% of the country's total wine production, and in particular Eiswein from the eastern province of Burgenland is regarded as one of the most highly prized in the world, making it a product which sells for a significant price.

For the best ice wine they need a temperature between -10 and -7°C.

But the loss of this year's Eiswein harvest is not the biggest worry, a bigger concern is that the warm weather will mean that the vines start to bloom which could result in a catastrophe if a late winter then arrives.