The ubiquitous and versatile grapes Riesling and Trollinger, which respectively produce a dry white and deep red wine, are struggling to survive in the heat and drought.
Riesling grapes, in particular, are sensitive to strong sunlight. If they ripen in September instead of October, as experts suspect they will, they will be susceptible to the rot fungi botrytis.
“We cleared out our Riesling variety at the Kaiserstuhl because growing it no longer makes sense in times of rising temperatures,” said the director of the State Viticulture Institute in Freiberg, referring to vineyards in the Upper Rhine Valley.
These new types of grapes, known as the “piwi varieties,” can adapt to the new climate and withstand the fungal mildew.
They have a 3 percent market share of the total cropland in Germany, most of which can be attributed to the red wine grape Regent, well-known for its resistance to fungal diseases.
Reinhard Töpfer, the director of the Julius-Kühn Institute for grapevine breeding in Siebeldingen expects that the piwi varieties to expand to 10 percent of the market share.
“Climate change will force us to change grape varieties,” Töpfer said.
Piwi varieties are also more organic, as they do not need to be sprayed with pesticides as often as conventional grapes.
Nevertheless, pesticides are not set to disappear from vineyards in the near future.
“Mushrooms are very clever,” explained private vine grower Volker Freytag from Neustadt an der Weinstraße. “They multiple billions of times and find ways to get around the pesticide.”
Producing wine from fungi-resistant grapes takes a long time, around ten years, in fact.
First, wild vines from America or Asia are cross-pollinated with European grape varieties. Once these mature into a significant amount of grapes, growers can estimate the amount of wine they will produce.
Taking into account crossbreeding, testing, and certifying, the whole process of breeding a new grape variety can take as long as 25 to 30 years.
Producing new grape varieties is doubly difficult. Not only to winemakers need to cultivate fungi and climate change-resistant grapes, they also need to make sure they produce a tasty wine that is marketable.
“With the piwi varieties we have an great opportunity to discover new wine flavours,” Köpfer said. “We should appreciate taste diversity, diversity in general, and culture differences. Many customers buy Pinot Gris because they simply know it. They might be happier with a piwi wine like the Johanniter wine.