Concept
PIWI
Pilzwiderstandsfähige Rebsorten: crosses between Vitis vinifera and other Vitis species that resist fungal disease. Central to EU climate adaptation. Voltis is the first PIWI in a French AOC.
What it is
PIWI is short for the German Pilzwiderstandsfähige Rebsorten, literally “fungus-resistant grape varieties”. It refers to grapes developed through targeted crossing to better resist fungal diseases like powdery and downy mildew, and sometimes botrytis.
PIWIs arise from interspecific crossing: Vitis vinifera (the European wine grape) is crossed with species like Vitis rupestris, Vitis riparia or Vitis amurensis, which naturally carry disease-resistant genes. The result is a grape that sits closer to vinifera than classic American hybrids, requiring less pesticide while keeping a vinifera-like flavour profile.
History and breeding programmes
Serious PIWI development began in the 1950s, mainly in Germany, Switzerland and Austria. Key institutes:
- Geilweilerhof (Germany, Pfalz): pioneers with Regent (1967)
- Freiburg (Germany, Baden): developer of Solaris (1975), Johanniter, Souvignier Gris, Cabernet Cortis
- Geisenheim (Germany, Rheingau): focus on classic crossings with Riesling-like profiles
- Agroscope (Switzerland, Wädenswil): Divico, Divona
- INRAE (France, Colmar): Voltis, Floreal, Artaban, Vidoc (the ResDur series)
INRAE’s ResDur programme (started around 2000) produced the first French PIWIs with double resistance to powdery and downy mildew. Voltis comes from this series.
Why PIWIs matter now
Three reasons:
- Pesticide reduction: traditional Champagne vineyards receive 12 to 15 fungicide treatments per year. PIWIs typically need 2 to 4, a 70-90% reduction.
- Climate adaptation: warmer and wetter weather in Northern Europe increases the risk of fungal outbreaks. PIWI resistance provides a buffer.
- EU regulation: the European Farm-to-Fork strategy aims for a 50% pesticide-use reduction by 2030. PIWIs are a direct technical route there.
Status in AOCs
For decades PIWIs were excluded from classical AOCs because they are not pure Vitis vinifera. That is changing. The Comité Champagne accepted Voltis in 2022 under a specific statute: VIFA (Variétés d’Intérêt à Fin d’Adaptation), maximum 5% of plantings per producer. The first PIWI ever in a major French AOC.
Other regions follow slowly. Bordeaux experiments with Souvignier Gris and Vidoc under similar adaptation statutes. Italian DOCs in Trentino and Friuli allow Solaris and Johanniter within separate categories. Outside AOCs (in Vin de France) PIWIs have been permitted for years and the range is growing rapidly.
Where the scepticism comes from
Two legitimate concerns among classical winemakers:
- Flavour profile: early PIWI generations (such as Regent, Solaris) often had a recognisable “hybrid” tone: spicy, sometimes green, not typically vinifera. Later generations (Souvignier Gris, Voltis) are significantly improved but the legacy lingers.
- Resistance stability: fungi evolve. A PIWI that is resistant now may work less well in 20-30 years. Long-term data is partly missing.
For lovers of classical vinifera styles, Voltis will never be the same as Chardonnay. But as a component in a blend it can reduce pesticide pressure without making the wine style unrecognisable.
Frequently asked questions
Is a PIWI wine inferior to classical vinifera?
Not automatically. A well-made PIWI wine from modern varieties (Souvignier Gris, Floreal, Voltis) can be indistinguishable from average vinifera in blind tasting. Early generations had clear flavour issues; recent generations far less so.
How many PIWIs are allowed in Champagne?
Voltis has been permitted since 2022 under the VIFA statute, up to a maximum of 5% of plantings per producer. Other PIWIs are not allowed. The Comité Champagne is considering further expansion in 2026-2028 based on trial results.
Which PIWI wines can I drink now?
In the UK and Netherlands: PIWI wines from Apostelhoeve (NL), Domein Aldeneyck (Belgium), or German producers like Schloss Vollrads (Souvignier Gris experiments). For Voltis-Champagne it is too early: the first plantings from 2022-2023 only yield commercial wine from 2026-2027.
What’s the difference between PIWI and organic?
No overlap. PIWI concerns genetics (disease-resistant crossings). Organic concerns cultivation method (no chemical pesticides, regardless of grape). A PIWI can be grown organically or not; a classical vinifera can also be grown organically. PIWIs do make organic farming easier because they need fewer treatments.