Impact of elevated temperature and water deficit on the chemical and sensory profiles of Barossa Shiraz grapes and wines

Abstract

Background and Aims Interactions are the main causes of complexity in field experiments; however, no studies have combined water and temperature regimes in field‐growing vines. Here we assessed grape and wine attributes from a field trial where these factors were directly manipulated. Methods and Results The experiment consisted of Shiraz vines grown in a 22 factorial experiment with two temperature (control and heated) and two water regimes (deficit and irrigated) during two seasons (2010/11 and 2011/12). The sensory and compositional characteristics of grapes and wines were assessed in both seasons, whereas a detailed profile of the phenolic substances was determined by spectrophotometry in 2011/12. We found additive effects (i.e. lack of interaction) between temperature and water for berry mass and components, fruit composition (titratable acidity and pH), grape phenolic substances (12.5% ethanol‐extracted and most of the 70% acetone‐extracted), wine phenolic substances (chemical age 2), and wine sensory traits (floral aromas and berry flavours). Significantly, previously unrecorded interactions between temperature and water were found for grape phenolic substances (70% acetone‐extracted skin and seed tannins and total phenolic substances per berry), wine phenolic substances (colour density, tannins and phenolic substances) and wine sensory traits (floral aromas, cooked fruit flavours and tannin structure). Conclusion The effect of water deficit leading to colourful and flavoursome wines rich in phenolic substances may not be held under high temperature. Significance of the Study Our study anticipates the drier and hotter climate of the Barossa Valley, and provides industry with indications of a shift in wine profiles that would require technological innovation to maintain the identity of Barossa Shiraz.

Irrigation and Leaf Removal Effects on Polyphenolic Content of Grapes and Wines Produced from cv. ‘Agiorgitiko’ (<i>Vitis vinifera</i> L.)

“…Those same two treatments were the ones with the highest total tannin content. Irrigation alone, on the other hand, led to the lowest total tannin content, in contrast with other study (Bonada et al, 2015) that suggests that water availability has no effect on the content and concentration of tannins, phenolic substances and skin-and seed-derived tannins. Leaf removal seems to have caused a decrease in total phenols (expressed as gallic acid equivalents).…”

“…In previous studies, water deficit did not alter the concentration of seed tannins in 'Shiraz' and 'Cabernet Sauvignon' (Koundouras et al, 2009), while in two recent studies, irrigation resulted either in decreased content of tannins in 'Cabernet Sauvignon' seeds (Casassa et al, 2015) or increased content of both seed and skin tannins in 'Shiraz' grapes (Bonada et al, 2015).…”

Grape Ripening Is Regulated by Deficit Irrigation/Elevated Temperatures According to Cluster Position in the Canopy

“…Climate condition, namely high temperature along the growing season is considered a putative constraint to the implementation and success of the deficit irrigation regime (Shellie, 2011). Also, the interaction between elevated temperature and water deficit is considered the main cause of variability in field experiments results (Bonada et al, 2015) namely in what concerns the ripening of wine grapes (Real et al, 2015). …”

“…Bonada et al (2015) related an advance of the onset of berry net water loss by elevated temperature under water deficit, which hastened berry ripening and altered the balance of sensory traits.…”

“…The effect of temperature on berry composition has been studied extensively and the negative impact of high temperature on anthocyanin content was reported (Spayd et al, 2002; Mori et al, 2007; Sadras and Moran, 2012; Bonada and Sadras, 2014; Bonada et al, 2015). Nonetheless, to date, there appears to be a scarcity of knowledge of the performance of different varieties exposed to a combination of high temperatures and water stress during the growing seasons and under vineyard conditions (Greer and Weedon, 2013).…”