Rekindling the interest in PIWI

Dear Editor,

I have worked in viticulture intermittently for 25 years plus. Back in 2000, I undertook some specialist vine propagation training in Germany and the company I worked for had a strong interest in PIWI grape varieties. 

Since then I have continued to be involved with these grapes in varying aspects from breeding, field trials, propagation, planting and growing, winemaking, and attending related events. 

In the UK, it seems that the interest in PIWI vines is a little slow in getting started and I thought that some technical insight regarding the progressive development of new plants from breeding would be of interest to your readers. 

Most people working in the world of producing wine are familiar with the concept of PIWI vines, which are increasingly gaining credibility. The German based organisation, PIWI International, does a good job to promote these varieties and some readers will even have tasted a few PIWI wines as well they have, for some years, been available at numerous trade fairs. 

The name PIWI comes from the combination of Pilze (fungus) which is abbreviated to ‘PI’ and withstanding which is shortened to ‘WI’. As the name suggests, PIWI are fungus resistant grape vines. There is very little by way of resistance to fungal attacks in Vitis vinifera and so PIWI varietals have evolved out of trials in crossings.

In early days, this work was undertaken while seeking some form of Phylloxera protection prior to the development of grafting techniques. Purists and traditionalists frequently (and rightfully so to!) bemoan a loss of desired flavour in these crossings. With the increased use of grafted vines, the breeding of new varieties slowed right down, but there has always been some interest kept alive, as these PIWI vines hold other merits.

There is much to be learnt about in this direction of progressive viticulture and how new genetics can benefit both the environment as well as growers in a cooler climate. PIWI varieties have both better disease resistance and early ripening properties. 

Over the years there have been more growers looking to go down a path of absolute minimal chemical usage. Some growers claim that they are having to spray more frequently (perhaps because fungus is becoming more robust and resilient) but this is seen by many to be bad practice. 

The development of an interest in organic, or similar, production methods in recent years, has successfully rekindled the interest in PIWI grapes. There has always been research taking place (it might be of interest to note that the early ripening red grape, Regent, from the German vine breeders at Geilweilerhof in the Pfalz, is now some 50 years old) but more recently there has been a marked increase of new varieties from both private vine breeders and the larger vine nurseries. 

With this the vines are getting better. There is more reliable resistance from complex combinations of introduced genetics and a new range of flavour profiles too, allowing diverse styles of wine to be produced.

Some PIWI varieties offer higher yields compared to some presently grown vines, and while they fit in well with our increased concerns about the use of chemicals, there are lower growing costs and a simpler form of vineyard management may be possible too. 

The newer PIWI vines often show a shorter growing season and are able to produce wines in areas and countries that previously could not grow wine grapes. Coupled to an interest in ecological or environmental matters, it is interesting to note that many new vineyards in places like the Netherlands, Denmark, and even Sweden, only grow PIWI vines. These are often successful winemakers as well, not simply small scale ‘hobbyists’.

There are currently many excellent wines being produced from PIWI varieties and these early ripening properties could certainly give UK growers potentially riper grapes and with that, genuine potential for the development of still wines in a range of styles. 

I’ve heard it said: “PIWI wine, what’s not to love?”. Well, each to their own perhaps, but increasingly growers are going to be ‘cornered’ by the interests of consumers, and PIWI certainly offer growers a beneficial way forward, in my view.

Sam Doncaster

Dear Sam,

Thank you for sharing your thoughts on the potential benefits of PIWI vine varieties for UK growers. Indeed, in our challenging climate, disease resistant vines can help to alleviate some of pressure our vineyards managers face. 

Back in June 2019, I attended WineGB’s winemaking technical conference, where there was a talk and structured tasting of six wines produced from new disease resistant, early ripening varieties deemed suitable for sparkling wine. These included the PIWI varieties Soreli, Sauvignon Nepis and Sauvignon Rytos as well as three Pinot blanc and Pinot noir crosses, 109-052, 156-869 and 156-537.

Bred from a collaborative programme started in 2006, these varieties are resistant to Downy and Powdery mildew and have other desirable characteristics such as tolerance to Botrytis, good cluster formation, thick skin to deter SWD and tolerance to low winter temperatures. 

While, sadly, I remember being largely disappointed with the final wines on tasting in June, there are a number of PIWI varieties making a real name for themselves in the UK viticulture world including Cabernet cortis, Divico, Orion, Phoenix, Pinotin, Rondo, Seyval blanc and Solaris. If any readers have any unusual PIWI varieties planted, I would love to hear from you.

Victoria Rose, editor

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