Addressing exposure of chardonnay in Queensland vineyards - Part 2

Abstract

An extension project has been undertaken in a number of vineyard sites in Queensland over the 2009/10 growing season. This project, led by Ursula Kennedy and Robert Learmonth from the University of Southern Queensland, has focussed on the effects of fruit exposure by way of different canopy management treatments on the fruit and wine quality of Chardonnay and Shiraz. Preliminary findings of effects on Chardonnay were presented earlier this year, and this article further discusses impacts of exposure on fruit quality and also final wine quality. Exposure is an important issue to growers and winemakers in Queensland as the state’s vineyards are the most northerly and amongst the highest in altitude in the country, thus being subject to in very high levels of ultra violet radiation. Sun exposure in white wine grapes may result in increased phenolic concentration (Macaulay and Morris, 1993), and berry shrivel and browning (Tarara et al. 2000) while in red varieties can lead also to sunburn but also can impair anthocyanin accumulation or in fact lead to degradation of anthocyanins (Haselgrove et al. 1999, Dry 2009).