By Stuart Pigott and Paula Redes Sidore
Fungal disease remains the biggest obstacle to organic winegrowing, even as the organic wine category continues to grow rapidly due largely to consumer awareness to environmental issues and climate change. So their resistance of these wines to fungal infection makes the so-called PiWi grape varieties the cool new route to organic wine production.
This makes the odd sounding ‘PiWi,’ the abbreviation of the German-language technical term Pilzwiderstandsfähige Traubensorten, or fungal-resistant hybrid grape varieties, one of the most important new wine buzz words at Prowein 2024.
The truth is that even organic and biodynamic producers must spray their vines with fungicides to protect them from the twin threats of downy and powdery mildew (technical terms: Peronospera and Oidium), fungi accidentally imported to Europe from North America in the late 19th century that cannot be eradicated. However, the lists of permitted sprays for organic and biodynamic producers are far more restrictive than the wide range of possibilities available to conventional winegrowers.
In moist winegrowing locations like Northeastern Italy, Burgundy in France or the Mosel in Germany given an average growing season conventional producers need to spray 7-8 times, while organic producers need to do so a dozen or more times, because what they spray has a weaker effect on those destructive fungi. This is not only extra work and costs, but the amount of tractor fuel used is correspondingly greater, which means more carbon dioxide emissions. In contrast, the natural properties of PiWi vines, mean that vineyards need as few as 2-3 applications of organic sprays per growing season. You don’t need to be Albert Einstein to spot the great combination of ecological, carbon footprint and economic advantages with PiWis. The figure of 80% is widely accepted.
No wonder wine producers across Europe have begun experimenting with PiWis. A few wines made from these grape varieties have been around for a time, but it is only now that commercialization on a more serious scale is beginning. This has a lot to do with the work of Swiss vine breeder Valentin Blattner, who developed many of the new generation of PiWi grape varieties, such as Cabernet Blanc, Cabertin and Pinotin. Blattner’s pioneering work has allowed winegrowing to thrive in regions long deemed far too cold.
An excellent example of a serious commercial PiWi producer is the Winzer Krems co-operative in the Danube Valley of Austria. They currently sell three wines made from PiWi varieties developed in Austria: Blütenmuskateller, Donauriesling and Donauveltliner. And yes, those wines are reminiscent of Muskateller/Muscat, Riesling and Grüner Veltliner. Nearby Weingut Geyerhof, one of the pioneers of organic viticulture in Austria, offers a barrel-fermented Donauriesling. While Steiermark/Styria in Austria dedicates 2.9 % of the region’s plantings to PiWi varieties, double the Austrian average. The Ploder-Rosenberg winery is one of the leaders there.
We can’t wait to taste the 2023 vintage wine that Roberto Anselmi of the Soave region, one of Italy’s most famous white wine producers, from the PiWi varieties Aromera, Riesling Resistente and Souvignier Gris. Anselmi is the first famous name winemaker to make a major commitment to PiWis.
Then there’s the German Zukunftsweine.de or future wines movement, a group of producers who produce dozens of wines from PiWi varieties. In Germany 1,671 hectares are planted with the well-established PiWi Regent, making it the 15th most widely planted grape variety. Together all PiWis account for 3.5 % of Germany’s total vineyard area. However, around 10 % of all new vineyard plantings in Germany are of PiWis, so they are rapidly expanding their share. One of the first German winegrowers - inspired by Valentin Blattner - to use PiWi (specifically the Cabernet Blanc grape variety) 20 years ago was the Graf von Weyher winery in the Palatinate.
Another well-established German-bred Piwi called Solaris (crossed by the vine breeding institute in Freiburg/Baden in 1975) plays a leading role in the development of viticulture at the polar new northern limit of European viticulture in Poland, Denmark and even further north in Scandinavia.
These examples beg the question why something like this didn’t happen earlier? The first answer is that PiWis are not pure Vitis vinifera, the wine grape, and for a long time non-vinifera grapes had the image of being inherently inferior in aroma and flavor to vinifera varieties like Chardonnay, Riesling, Tempranillo and Sangiovese. We have to be frank with you and admit that we haven’t yet tasted wines from PiWis that match the greatest wines from vinifera varieties, but we have tasted plenty of good wines made from PiWis, both as single varietals and as blending partners, and their prices were often rather friendly. Quality and value-for-money can be found by consumers.
Although modern Piwi work began with Valentin Blattner in 1982, the idea of crossing Vitis vinifera, the wine grape, with other species of Vitis to create new varieties (technical term: interspecific hybrids) to create grape varieties resistant to pests goes back to the Phylloxera crisis in 1860s France. It was then that work on breeding what later became known as the French hybrids began. Their fungal resistance was a welcome bi-product of the sought resistance to the Phylloxera mite that ate the vine roots.
It’s a little known fact that a century after that endeavor began there were still vast plantings of French hybrids in France. For example, in 1960 there were still roughly 30,000 hectares of them in the Bordeaux region compared with 19,000 hectares of Semillon and 12,000 hectares of Merlot, the then most widely-planted vinifera varieties! In 1975 the French government implemented a national ban on new plantings of these French hybrids, ending this chapter in French wine history. That, and the restrictive rules of the French AOC appellation rules, are the reasons that France lags behind with PiWis.
The French American hybrids are widely associated with winegrowing in the Eastern States of the US, although the first commercial planting there was as recent as 1944 in the Finger Lakes region of upstate New York. By the late 1960s and early 1970s quality wines from varieties like the white Seyval blanc and Vignoles, plus red Chambourcin were staples of the New York wine industry and widely planted in other US states along the eastern seaboard. These varieties are now enjoying a modest renaissance there as alternative winemakers like Nathan Kendall and free-thinking somms like Pascaline Lepeltier explore their untapped potential. And so the wheel of wine fashion comes full circle.
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