With a network of mini-demonstration sites within commercial vineyards being the backbone of the GEN-Z Vineyard Project, this endeavour launched by Vinpro six years ago under the management of well-known and loved viticulturist Francois Viljoen and his team of viticulturists, is going from strength to strength.
There are more than 50 demos on various soil types spread across various wine regions, and new ones are planted every year. This season the team monitored over 20 demo sites across the various wine regions.
“The GEN-Z Project aims to create experimental plots in commercial vineyards and then gather information and share it with producers by taking a more practical approach at demo sites and field day sessions,” says GEN-Z Vineyard Project viticulturist, Emma Carkeek. “The project is multidisciplinary and includes rootstock trials, clone gardens and cover crop plots, among others.”
Olifants River alternative cultivars demos
At the start of the project in 2015, it was decided in the Olifants River region to focus specifically on alternative cultivars that are not grown on a large scale in the region. These include white and red cultivars (such as Verdelho, Vermentino, Tempranillo and Carmenere) that show potential and can produce good production and quality in the region’s warm conditions with its sharp heat peaks. The first rootstocks were planted between commercial blocks as early as 2016 and the amount varies between 150 and 250 rootstocks per trial which yields enough grapes for the producer cellars in the region to make wine from.
The project is still ongoing and according to Gert Engelbrecht, regional consultant for Olifants River, it would not have been possible without the cooperation of a large group of persons. This includes the producers who are willing to plant, grow and deliver the vines separately, the viticulturists who help with planning and intakes, the winemakers who find space and time in their cellars at harvest time and then also Namaqua Wines and Lutzville Vineyards who make facilities and man hours available. Vititec also helped by processing and supplying these small rootstock orders.
The wines made from these cultivars are tasted annually by winemakers and viticulturists in the region and notes are carefully made and stored, as well as basic production data.
“Thus far we can see that Verdelho is a good option for making fresh and delicate white wines in a warm area as it ripens very early. On red sandy soils where it is pruned mechanically, production of 30 t/ha and more is possible,” says Gert. “Vermentino performs well with its fresh citrus flavours and keeping ability, but effective shell contact is necessary for good recoveries. Year after year the Tempranillo wines display complex fruit flavours, and this cultivar is also an early alternative to Pinotage. The Carmenere, though a challenging cultivar, has proven itself and has already won wine show medals,” says Gert.
The GEN-Z interplanting project is also gaining momentum offering valuable knowledge to the Olifants River producers. The industry may see these alternative cultivars lend itselve to large-scale commercial cultivation in future adding value to the region’s wine offering. The project continues with new plantings of Assyrtiko, Tannat, Agiorgitiko and Piquepoul Blanc that will soon yield grapes.
What’s up with Sauvignon Blanc?
The GEN-Z Vineyard Project has established more than four different Sauvignon Blanc demos since 2016. In 2013 a rootstock demo was planted at Alexanderfontein in Darling, consisting of 10 different rootstocks and in 2018, a clone demo was planted in a nearby vineyard to compare 11 Sauvignon Blanc clones. In Durbanville at the De Grendel demo site, also planted in 2018, 11 Sauvignon Blanc clones were planted on one rootstock.
“The Sauvignon Blanc clone and rootstock demos at Alexanderfontein and De Grendel compare the performance of various Sauvignon Blanc clones on a single rootstock by monitoring and gathering data from both locations,” Emma explains. “Each clone is grafted onto one rootstock and planted on one soil type but under different growing conditions with the Alexanderfontein demo managed under dryland conditions and the De Grendel managed as an irrigated vineyard.”
This season in addition to yield monitoring and juice analysis, the winemaking potential of the 11 clones is being assessed by micro vinification. Micro vinification is applied to a selection of demos based on the age and type of demo. This technique allows for comparison between winemaking potential of the various clones. Due to the high cost of micro vinification, the number of wines being made is limited per season across all demos.
As the team only have two seasons’ worth of data from each of their Sauvignon Blanc clone demos, it’s still too early to draw any conclusions from the available data and a few more seasons are needed to examine the yields and juice quality.
The next steps according to Emma will be to plant bigger demos and therefore fewer combinations, rather than planting 10 clones or everything that’s available, to also allow for medium-scale winemaking. “This will give a better idea of the possible wine quality of that clone,” Emma concluded.
For more information about the demo sites and findings in all the wine regions, go to www.genz.co.za.
