This article is part of our special report European winemakers grapple with environmental questions.
The year 2018 was an excellent vintage for German wine, despite the drought. However, with the climate getting warmer, Riesling, Germany’s most famous wine, could start tasting differently. EURACTIV Germany reports.
With the taste varying between dry and sweet, its acidity still gives it a pleasantly fresh note. These are the qualities of Riesling, Germany’s most popular wine.
However, the future of the so-called ‘golden grape’ remains uncertain.
“Climate change has reached us. During the Riesling’s vegetation period, which runs between April and October, the average temperature has risen by more than one degree. And this changes the wine’s character,” explained Ernst Büscher, wine connoisseur and spokesperson for the German Wine Institute.
Riesling enjoys the cool weather because it takes a long time to mature and develop aromas. Since 1988, however, German wine growers in Rheingau and other wine-growing regions have gradually been experiencing warmer summers.
Besides, extreme precipitation and hailstorms, which can destroy entire harvests, have become more commonplace.
Nevertheless, 2018 was a great year and winegrowers were, of course, pleased. This is despite the hot summer, during which the vineyards only benefited from 54% of the usual rainfall. Grapevines are usually not artificially irrigated, as this would require enormous amounts of water.
This time, however, it had worked without the usual rainfall, given that “Riesling is relatively insensitive to drought due to its roots reaching so deep into the soil. Last year, winegrowers were sometimes surprised to see where the vines got their water from despite the drought,” Büscher said.
Wine grapes with sunburn
For the production of high-quality sweet Riesling wines, such as the so-called ‘beeren– or Trockenbeerenauslesen‘, the heat would even have a positive effect, the wine expert explained.
But this does not necessarily apply to Riesling. Although the heat drives its growth faster, the Riesling is nevertheless sensitive to extreme sunlight and just like human beings, these can also get sunburnt.
Besides, the grapes would also ripen too early, before they develop the fresh taste typical of Riesling, and become sweeter instead.
“The sugar content of the grapes is much higher today than in the past. The values are sometimes twice as high as in the 1960s and1970s,” said Otmar Löhnertz, a professor of soil science and plant nutrition at the Geisenheim University of Applied Sciences, which specialises in viticulture.
More sugar in the grapes means higher alcohol levels in the wine, which is not necessarily a good thing.
“Alcohol carries flavours. If a wine’s alcohol content amounts to 13% or 14% rather than 11%, the taste, fermentation process and ageing behaviour change. That is when we speak of a different style of wine,” Löhnertz explained.
The researcher said that global warming will change Riesling-type wines.
“In the future, Riesling will taste completely different,” he added.
No longer Riesling
However, this is still not the case because winegrowers have been using targeted cultivation measures to counteract these issues to ensure their Rieslings mature for as long as possible.
By removing the leaves, for example, sugar production can be curbed, and a different orientation of the vines on the vineyard can also protect the plants from too much sunlight. Theoretically, the plant could also be genetically modified, but the wine produced could then no longer labelled a Riesling.
Winegrowers have no choice but to wait for natural mutations in the vine that make it more weather-resistant or allow it to mature later. But these processes are very slow. It takes at least 20 years until enough clones of a mutated Riesling plant are available for it to be ready for the market.
“At the institute, we try to come to grips with the issue of how we can adapt cultivation systems so that we can also produce fresh-tasting wines like Riesling under warmer conditions,” the viticulture researcher Löhnertz said.
Since vines have a 30-year-lifespan, adapting the permanent crop to weather conditions appears to be quite the challenge.
“One could also say goodbye to Riesling and breed new wine varieties accordingly. But the future consumer also wants to have his Riesling from the Rheingau in the future. Wine consumers are quite emotionally attached to the product,” Löhnertz added.
Riesling, which has been cultivated for more than 500 years, is the most popular German wine. Almost a quarter of the country’s vineyard area is devoted to Riesling, which accounts for around half of global production.
In other words, Riesling is not just part of European drinking culture but also an economic factor.
Winegrowing in Schleswig-Holstein?
A new wine market emerging in the north is appearing to be a new challenge for winegrowers in Southern Germany.
In Schleswig-Holstein, Mecklenburg-Vorpommern and even Lower Saxony, new wine-growing areas have emerged since 2016. But they have only appeared in small numbers, as Germany only permits a 0.3% growth of the wine-growing regions each year due to current EU restrictions intended to prevent the oversupply of wine.
Büscher of the German Wine Institute believes that winegrowing in the northern part of the country is inevitable in the future. But entry into the hard-fought wine business is not easy.
“Winegrowing is special, it requires a lot of specialist knowledge, but also technology, and it is associated with immense acquisition costs,” Büscher added. However, the traditional wine-growing regions are still confident that they will continue producing Riesling in the near future.
Löhnertz also sees opportunities for the German wine market.
“In a way, the German winegrowing industry is a ‘climate winner’. But we don’t know how the weather will change in the coming decades. The question is how long this will last,” Löhnertz added.
[Edited by Zoran Radosavljevic]