Resistant grape varieties: new grape genetics, new winemaking challenges
Resistant grape varieties, often referred to as PIWI varieties (from the German Pilzwiderstandsfähige Rebsorten), are attracting increasing interest across many wine regions as growers look for solutions that reduce vineyard inputs while maintaining wine quality.
Their contribution to more sustainable viticulture is well recognised. However, experience is also showing that these varieties may raise new questions once the grapes arrive at the winery.
While many resistant varieties contain more than 98% Vitis vinifera genetics, they do not always behave exactly like traditional vinifera cultivars.
What are we learning in the winery?
Current observations suggest that resistant varieties may differ from traditional Vitis vinifera in several areas:
- acidity degradation kinetics
- the relationship between sugar and phenolic maturity
- extraction behaviour
- aromatic composition
- pressability and clarification
As a result, winemaking practices developed for traditional varieties may not always be directly transferable.
Research is progressing rapidly and wineries are already adapting extraction, clarification, nutrition and redox management strategies when working with resistant grapes.
Souvignier Gris: a practical example
Among the resistant varieties attracting growing attention, Souvignier Gris has emerged as a particularly interesting case study.
Recent research has highlighted the presence of thiol precursors as well as compounds such as methyl salicylate precursors, which may contribute to distinctive aromatic expressions.
Based on these characteristics, Oenobrands explored three targeted vinification routes designed to emphasise different aspects of the variety’s potential:
- White fruits and fermentative esters
- Thiol expression
- Green and balsamic character
These examples illustrate how winemaking decisions can influence the final wine style and why resistant varieties deserve dedicated oenological approaches.
The more experience gained with resistant varieties, the more opportunities emerge to reveal their full potential.