Do high temperature extremes impact berry tannin composition?

The sensory definition of the aging bouquet of red Bordeaux wines has been shown to be structured around seven main aromatic nuances: “undergrowth”, “spicy” “truffle”, “fresh red- and black-berry fruits”, “liquorice”, “mint”, and “toasted” (1). Some of these descriptors are also used to describe the aromatic notes of old Champagnes (2) suggesting common volatile compounds between these two types of wine.

Context and purpose of the study. Berry sunburn in vineyards is a recurring disorder that can cause severe yield loss. As sunburn observations are often associated with heat waves, a link to climate change is likely.

The Fruška Gora mountain is a traditional wine-growing region in Serbia situated in the Pannonian Basin. Due to such a position, the vicinity of the Danube River and the presence of concave configuration, it is suitable for grape production. This paper provides analyses of spatial variations in meteorological parameters and grape juice quality within Fruška Gora wine region over three consecutive vintages (2018-2020). The examined period can be defined as warm with cool nights during September (AVG 18,9°C; GDD 1918°C; CI 12°CF) and with the presence of mesoclimatic variability. The East part of the study area was somewhat drier and hotter compared to other parts of the region. The analyses of grape must samples (190 in total) of five cultivars (Cabernet-Sauvignon, Merlot, Chardonnay, Sauvignon blanc and Grašac (Welschriesling)) commonly grown across the region (19 sites), were performed using Fourier Transform Infrared Technology (FTIR). Among all cultivars, Sauvignon blanc was harvested first in the East area (DOY=246±5, GDD at harvest=1552±74, 22.2±0.7 °Brix), while the latest harvest was recorded for Cabernet-Sauvignon in the West (DOY=283±5, GDD at harvest=1936±187, 23.4±1.0 °Brix ). Both the red and white cultivars had higher acidity and YAN in the grape must if the vines were grown in the North and East compared to South and West areas. According to PCA analysis, Grašac showed the lowest variation in grape must chemical composition. Thus, the results confirm that Grašac is the most stable cultivar in Fruška Gora. All monitored cultivars reached technological fruit ripeness by the end of the growing season. However, it was difficult to reach full ripeness of red cultivars, mostly beacuse of uncoupling of technolocical and phenolic ripeness. Thus, Cabernet-Sauvignon had higher variations in GDD sums at harvest compared to other cultivars, which probably increased variations in grape must quality.

Botrytis cinerea, a well-known grapevine pathogen, has more than 1200 host plants causing grey rot in grapevine berries. However, it can also result in a desirable phenomenon called noble rot under specific microclimate conditions. An extraordinary demonstration of this natural process can be observed in the creation of aszú wines within Hungary’s Tokaj wine region. Beside B. cinerea other fungi and yeasts are involved in the secondary metabolic development of the grape berry which contributes to the sensory and analytical characterization of noble rot wines.

La présente étude de zonage viticole a été faite dans la région de la vallée Central de Tarija(VCT), dans la ville de Tarija, au Sud de la Bolivie; une région avec plus de 400 années de tradition qui présente une vitiviniculture de haute qualité. La Vallée possède une surface total de 332 milles ha.; existant des vignobles entre 1660 y 2300 m.s.n.m. et dans ce rang d’altitude il existe 91 mille ha.