Climate change threatens Luxembourg's ice wine production

The tradition ice wine, or eiswein in Luxembourg, produced right at the end of the season, could soon disappear due to climate change.

"Our cooperative winemakers have no grapes left for ice wine. As far as I know, it has not been produced by any private winemaker this year," explains Harald Beck, viticulture consultant at the Vinsmoselle cooperative. "For ice wine you need several days of severe frost, preferably in November or December. In the face of climate change, the risk is very high that these conditions will not be met."

The viscous, aromatic and liqueur-like eiswein is made from frozen grapes. For this they must be left on the vine after harvest season in September and October.

In the deep-frozen fruit, some of the water forms ice crystals and stays inside the grapes. The result is a concentrated, low yield, but high sugar content juice.

During a mild winter, the ice wine harvest may not take place at all, meaning that an entire year's ice wine production would be lost.

Climate change is doubly unfavourable, explains Harald Beck. On the one hand, especially in the important first half of winter, frequently no persistent low temperatures are reached. On the other hand, the warm summer ensures early maturity. The grapes then need more frost, due to the sugar content, to freeze.

"Especially this year we had wonderful grade of grape," says Beck, but that means that consistent temperatures of below -7°C is needed to freeze the grapes.

According to his observation, severe frost in recent years comes only towards the end of winter, but then it is often too late for the eiswein. "The longer it takes, the harder it is to harvest healthy and unbroken grapes," he says.

To protect them from birds, winegrowers pack the rows of vines for eiswein into nets or foils, but decay and natural loss due to drying out, diminishes the harvest.

As an expensive niche product, could eiswein completely disappear as a product from Luxembourg winemakers along the Moselle? Beck shakes his head. He does not want to call eiswein a "discontinued product", however, he sees little chance in the coming years that winemakers take risks associated with eiswein.

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