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Hybrid grapes and PIWI - the resistant grapes of the future

Winemaking faces a challenge: traditional noble grapes are very susceptible to fungal diseases, so vineyards have to be intensively sprayed, often a dozen or more times a season. This is costly, labour-intensive and burdens the environment. The answer may be hybrid grapes, and especially PIWI varieties, that is grapes genetically resistant to fungus. They let chemistry be drastically reduced, while giving ever better wines. For some they are the future of sustainable winemaking, for others a controversy and a departure from tradition. In this post we will explain what hybrid and PIWI grapes are, how they are made, what benefits they bring for the environment and why, despite their advantages, they still meet resistance. It is a look at one of the most important changes in modern grape growing.

What hybrid grapes are

Hybrid grapes are grape varieties created from crossing the European grapevine, that is Vitis vinifera, with other species of the genus Vitis, often originating from America or Asia. These wild species have a natural resistance to diseases and pests, which the noble but sensitive European grapes lack. By combining them, breeders try to obtain varieties that keep the quality of European wines, while inheriting the resistance of their wild relatives. Hybrids are not a novelty, as they have been experimented with for a long time, especially after the phylloxera disaster. Old hybrids, however, had a bad reputation for mediocre taste. Modern varieties, including PIWI, are far more refined crosses that combine resistance with real quality potential. This is the key difference between old hybrids and today’s new-generation varieties, which are treated quite differently.

PIWI - resistant to fungus

PIWI is an abbreviation of the German word Pilzwiderstandsfähige, meaning resistant to fungus. It is a category of modern hybrid grapes whose main asset is high resistance to fungal diseases of the vine. They are created from crossing Vitis vinifera with other Vitis species, so they have a built-in, genetic defence against the most dangerous diseases. PIWI varieties show a high level of resistance to at least one fungal disease, such as downy mildew, powdery mildew or grey rot botrytis. It is precisely these diseases that force traditional growers to spray frequently. PIWI, thanks to natural resistance, need it far less. This makes them a flagship example of a modern, sustainable approach to grape growing. The name PIWI has become a recognisable mark of this movement, especially in German-speaking countries, where their research and cultivation are most advanced.

How hybrids are made

The creation of modern hybrids is a painstaking breeding process, often taking many years. Breeders cross the noble Vitis vinifera, responsible for the quality and taste of the wine, with wild Vitis species, carrying the genes of resistance. Then, through successive generations of selection and backcrossing, they strive to obtain a variety that combines the best traits of both parents: the taste and character of European wine with the resistance of the wild relatives. It is a balancing act: too many genes of wild species can give an unpleasant, wild aftertaste, and too few weaken the resistance. Modern breeding methods, including marker-assisted selection, have considerably accelerated and refined this process. Thanks to this, new PIWI varieties are ever closer in taste to classic wines, while keeping solid resistance. It is the fruit of decades of patient work by breeders, who keep refining these grapes, striving for an ideal combining quality and durability.

Less spraying, less chemistry

The greatest practical advantage of PIWI grapes is the drastic reduction in the need to use chemistry in the vineyard. Traditional, sensitive grapes require numerous antifungal sprays over the season, which is costly and burdensome. PIWI varieties, thanks to natural resistance, allow the use of synthetic pesticides to be cut by over eighty percent. This is far more than the fifty percent reduction target set by the European Green Deal. The cultivation of resistant hybrids can reduce the number of treatments in the vineyard by as much as half. Less spraying means not only a cleaner vineyard, but also lower costs, less work and lower fuel use for tractor passes. It is a measurable, practical benefit that translates into both ecology and the economics of the farm. For many growers it is precisely this reduction of chemistry and costs that is the main reason for interest in PIWI grapes.

Environmental benefits

The environmental benefits of PIWI grapes reach far beyond the reduction of pesticides alone. A smaller number of treatments in the vineyard means a significant drop in greenhouse gas emissions related to the passes of farm machinery. Rarer tractor passes also mean less compaction and destruction of the soil, which favours its health and biodiversity. Less chemistry means cleaner groundwater and a smaller burden on local ecosystems. Added to this is the reduction of occupational risk for workers, who have less contact with sprays. All of this adds up to a far lower environmental footprint of cultivation. In times of growing ecological awareness and pressure for sustainable agriculture, these benefits cannot be overestimated. PIWI grapes thus fit a wider trend of striving for winemaking more friendly to the planet, combining wine production with care for the environment, soil and local communities.

Climate resilience

In the face of climate change, the resistance of PIWI grapes takes on additional significance. A warmer and more variable climate favours the development of fungal diseases, and violent weather events increase the pressure on vineyards. Resistant varieties are better prepared for such challenges, coping in conditions that for sensitive grapes would be deadly or would require even more intensive spraying. In humid, fungus-favouring years the advantage of PIWI becomes especially clear. This resistance makes them an attractive choice not only for ecological reasons, but also as insurance against the whims of the weather and new threats. In regions of difficult, humid climate, where traditional winemaking is especially exposed to disease, resistant grapes can even make profitable cultivation possible. This makes them an interesting option for a future in which stability and resilience will be ever more valuable.

Well-known PIWI varieties

The world of PIWI is already a whole palette of varieties, both white and red, of growing renown. Here are a few well-known examples:

The table shows that PIWI is not one grape, but a whole family of varieties of different character. Many of them bear names alluding to the classic grapes from which they partly descend. The list keeps growing, because breeders continuously introduce new, ever better resistant varieties.

The barrier: acceptance and law

Despite their advantages, PIWI grapes meet real barriers. The first is consumer acceptance: the word hybrid still arouses mistrust, because old hybrids had a bad reputation. Many drinkers fear that resistant varieties give worse wines, which today is ever less true. The second barrier is regulations. In many classic appellations and quality systems, especially those attached to the traditional Vitis vinifera grapes, hybrid varieties were historically not permitted for the production of the highest category of wine. This limits their use in prestigious regions. The situation is slowly changing with growing ecological pressure and evidence of PIWI quality, but the resistance of tradition and regulation remains strong. Overcoming these barriers, mental and legal, is the key to the spread of resistant grapes. Educating consumers and gradual changes in regulations are as important here as further progress in breeding itself.

Quality in the glass

The key question is: are PIWI wines good? Here enormous progress has been made. Old hybrids really were sometimes weak in taste, with a characteristic, unpleasant wild aftertaste. Modern PIWI varieties, however, are a completely different league: thanks to decades of selection they can give wines of real complexity, character and quality, suitable even for premium production. More and more winemakers create from them wines that in blind tastings are hard to distinguish from classic ones. Of course the quality depends on the particular variety and the hand of the winemaker, as with any grape. But the thesis that PIWI by definition means worse wine is now out of date. For the open-minded consumer it is a chance to discover new, interesting flavours, and at the same time support more sustainable winemaking. The best PIWI wines prove that resistance and quality do not have to exclude each other, but can go hand in hand.

The future of winemaking?

Are PIWI grapes the future of winemaking? More and more indicates they will play an important role in it, although they will not completely replace the classic grapes. Interest in them has been growing since the nineteen-nineties, and the leaders of research and cultivation are Germany, Switzerland, Austria and Italy. In the face of ecological pressure, rising costs of chemistry and climate change, their advantages become ever harder to ignore. We will probably see a gradual increase in their share, especially in organic winemaking and regions of difficult climate, and a slow opening up of regulations. The tradition and prestige of the classic grapes will remain strong, but PIWI may become an important, sustainable complement. It is one of the most interesting directions of development in modern winemaking, combining science, ecology and quality. We write more about how place shapes wine in our post on terroir.

The key points in a nutshell

Hybrid grapes are crosses of the European Vitis vinifera with other Vitis species, and PIWI varieties, from the German term for resistant to fungus, are their modern, refined version. Their great advantage is resistance to fungal diseases, allowing synthetic pesticides to be cut by over eighty percent and the number of treatments to be reduced by as much as half. This gives enormous environmental benefits: fewer emissions, healthier soil and cleaner water, as well as resilience to climate change. The barrier remains consumer mistrust and the regulations of classic appellations, but modern PIWI already give wines of genuinely high quality. Want to discover new grapes and record your impressions? Keep notes in the GustoNote app. See also our posts on terroir and how wine is made.