Die invloed van stokontwikkeling, lowerdigtheid en klimaat op die gehalte van Pinotage

Project Number
WW 12-14

Project title
Die invloed van stokontwikkeling, lowerdigtheid en klimaat op die gehalte van Pinotage

Project leader
Van Schalkwyk, D

Project description
Temperatures measured within the canopies indicated that long periods of high temperatures occurred during January and February (2003 -2007). Temperatures above 35°C for 6 hours/day for 6 consecutive days were registered. These hot conditions resulted in long periods during which no photosynthesis occurred, excessive loss of leaves at some of the plots and sun burn of the exposed grapes. During these hot periods, grapes of the minimum canopy management treatments were less subjected to sunburn as more leave protection was available. Denser canopies are thus ecommended in warm regions and dry land Pinotage to prevent excessive exposure of bunches to direct sunlight. Pinotage reached optimal ripeness and were harvested between the second week in January and the second week in February. The mean January temperatures are therefore more accurate than that of February in classifying Pinotage cultivation areas into different climate regions. Minimum canopy management treatments yielded significantly more bunches and higher yields than the optimal canopy management treatments. Bush vines had significantly less bunches per vine and therefore produced significant lower yields than trellised vines. Significant differences in bunch-, berry mass and berry volume occurred to a lesser extent. Irrespective of the differences in yield etc. no significant differences in the overall wine quality of six or 24 month matured wines of bush or trellised Pinotage occurred, indicating no preferences for either vine structure. Optimal canopy management improved the canopy and density and thus microclimate conditions within the canopies of the different bush vine and trellis treatments but did not improve wine composition and quality in either of the three climate regions. Trellising however, improved berry and wine colour in climate region 2 and the opposite in climate regions 3 and 4.

Bush vines produced significant higher concentrates of phenols and had a higher anti-oxidant capacity. If the aim should be to produce wine with higher phenols concentrations and higher anti-oxidant capacity, bush vines could be recommended in climate regions 2 and 3. Although there is no significant proof to recommend either, bush vines or trellising in a specific climate region, significant differences in the wine quality of these vine structures were found at farm level, proving that terroir is important when deciding to establish bush or trellised Pinotage. Sensorial evaluation for aroma and wine quality proved that many differences in wine styles were evident and were identifiable with specific plots. There is thus no proof to make a broad recommendation for vine structure to be used in specific climate regions.

Poster(s)
De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. 27th National Congress of the South African Society for Enology and Viticulture, November, Somerset West, South Africa.

De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. SAAFost Congress.

Van Schalkwyk, D and Schmidt, A. 2006. The effect of climate, trellising and canopy density on the viticulture and wine performance of Pinotage: A preliminary report. 29th National Congress of the South African Society of Enology and Viticulture. 14-17 November, Somerset West, South Africa.

Presentation(s)
Van Schalkwyk, D. 2003. Management practices for Pinotage. South African Society for Enology and Viticulture Workshop, 18 September.

De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. 27th National Congress of the South African Society for Enology and Viticulture, 5-7 November, Somerset West, South Africa.

De Beer, D, Joubert, E, Marais, J, Van Schalkwyk, D and Manley, M. 2003. The effect of climate and vine management systems on the phenolic composition and total antioxidant capacity of Pinotage wines: Preliminary results. South African Association for Food Science and Techology (SAAFoST) Congress.

Van Schalkwyk, D. 2005. Management practices for Pinotage. Winetech Terroir Programme, 28 April, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa.

Van Schalkwyk, D. 2005. Die invloed van stokontwikkeling, lowerdigtheid en klimaat op die gehalte van Pinotage. Terugvoer van Pinotage produsente. 7 June, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa.

Van Schalkwyk, D. 2006. Management practices for Pinotage. 28 April. Winetech terroir programme, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa.

Van Schalkwyk, D. 2006. Die invloed van stokontwikkeling, lowerdigtheid en klimaat op die gehalte van Pinotage. Terugvoer van Pinotage produsente. 12 June, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa.

Article
De Beer, D E, Joubert, E, Marais, J, Van Schalkwyk, D, Manley, M. 2006. Climatic region and vine structure: Effect on Pinotage wine phenolic composition, total antioxidant capacity and colour, South African Journal of Enology and Viticulture, v. 27 (2) (p. 151-165)
Article.pdf

FinalReport.pdf

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