Abstract
Climate change and EU legislation regarding the reduction of pesticide usage pose challenges to winemakers across Europe, including those at the edge of the Mediterranean region such as South Tyrol (Italy). In addition, consumers and producers are increasingly conscious of environmental issues, meaning that sustainable wine production has become critical. Disease resistant hybrid grape cultivars (DRHGC), such as ‘PIWI’ grapes (German, Pilzwiderstandsfähige Rebsorten), offer a potential solution to both issues. However, these grapes differ from conventional Vitis vinifera cultivars in terms of chemistry and flavour profile and thus targeted winemaking methods are often needed, as has been recently discussed in Duley et al. (2023). Although modern DRHGCs have been bred to avoid many of the issues that plagued earlier hybrid cultivars, many are still low in tannins and high in proteins, leading to wines with low astringency, and high in pH and titratable acidity, leading to problems with microbial stability that cannot easily be solved via acidification. Additionally, both consumers and producers can be resistant to PIWI wines simply because they do not have familiar cultivar names. This report will discuss the literature on DRHGC chemistry, potential winemaking methods to produce high-quality wines from DRHGCs, and some preliminary data from chemical and sensory analysis of DRHGC and conventional wines from South Tyrol. The applicability of methods such as prefermentation drying of grapes, bentonite fining, thermovinification, and addition of
exogenous tannins will be discussed. It will also address the potential for DRHGCs to address issues relating to climate change and sustainability in winemaking and viticulture.
References
Duley, G, Ceci, AT, Longo, E & Boselli, E 2023, ‘Oenological potential of wines produced from disease-resistant grape cultivars’, Comprehensive Reviews in Food Science and Food Safety.