Project title
Investigation into the effect of winemaking techniques on Pinotage wine style and quality and development of procedures that will produce optimum quality wines

Project leader
Marais, J

Institution
ARC Infruitec-Nietvoorbij

Team members
Louw, A
October, F

Project description
The aim of the project is the investigation into the effect of winemaking techniques that will produce maximum quality wines, as well as the identification of Pinotage impact aroma components. The effect of cold skin contact prior to fermentation (1, 2 and 4 days at 10°C and 15°C, respectively) on fermentation bouquet volatiles (esters and higher alcohols), polyphenols (total flavonoids, total tannins and total anthocyanins) and wine quality was again investigated during the 2001 season. These components manifested in the wines in such a way that the 4 days skin contact at 10°C treatment produced the highest quality wines, which is in agreement with the results of previous seasons. In the investigations into the effect of different mixing techniques on the concentrations of esters, higher alcohols, total polyphenols and wine quality, punching-down and the rotor action produced the highest and comparable quality wines and the pumping-over action the lowest quality wines. Although chemical differences occurred between the 1 and 3 hour treatments, differences in wine quality between the two frequencies were minimal. The 2001 wines still have to be analysed and sensorially evaluated. After considering the results of the 2001 season, the mixing trials will be repeated during the 2002 season. The investigation into the relationship between grape colour and wine quality yielded promising results, and will be continued to develop a reliable quality prediction model. With respect to the identification of Pinotage impact aroma components, the investigation was expanded by testing a new SPME fibre, as well as by analysing homogenised Pinotage grapes. The identities of two possible impact aroma components, namely iso-amyl acetate and beta-damascenone, were again confirmed in wine. Further trials will be performed to confirm results and to identify possible additional impact components.

Presentation(s)
1. Marais, J. 2001. Effect of different winemaking techniques on the composition and quality of Pinotage wine. VIIIth Latin American Viticulture and Enology Congress, 12-16 November, Montevideo, Uruguay.
2. Marais, J. 2002. Bereiding van kwaliteit Sauvignon blanc en Pinotage wyne. Lutzville Farmers' Day, 8 October, Lutzville. South Africa.
3. Marais, J. 2003. Verlengde dopkontak vir die bereiding van hoër kwaliteit wyne. South African Society for Enology and Viticulture, Pre-harvest Meeting. 18 January, Stellenbosch, South Africa.
4. Marais, J. 2003. Pinotage wine profile. Pinotage Association. New vintage wine tasting function, 4 June, Stellenbosch, South Africa.
5. Marais, J. 2003. Relationship between grape colour and wine quality of red varieties. 27th National Congress of the South African Society for Enology and Viticulture, 5-7 November, Somerset West, South Africa.
6. De Beer, D, Joubert, E, Marais, J, Gelderblom, W C A, Van Schalkwyk, C A and Manley, M. 2003. Antioxidant capacity of wine: Effect of viticulture and oenological practices on phenolic composition and quality. 17th SAAFoST Congress, 1-4 September, Pretoria, South Africa.
7. De Beer, D, Fourie, B, Joubert, E, Du Toit, W, Marais, J and Manley, M. 2003. Wood maturation of Pinotage using barrels and alternative wood products: Effect on phenolic composition and antioxidant activity. 27th National Congress of the South African Society for Enology and Viticulture, 5-7 November, Somerset West, South Africa.
8. Rossouw, M and Marais, J. 2003. Phenolic compounds in South African red wines. 27th National Congress of the South African Society for Enology and Viticulture, 5-7 November, Somerset West, South Africa.
9. Marais, J. 2004. Effect of low-temperature, prefermentation skin contact and mixing techniques during fermentation on Pinotage wine composition and quality. Intervitis Interfructa 2004. 7th International Symposium on Innovations in Enology, 10-11 May, Stuttgart, Germany.
10. De Beer, D, Joubert, E, Marais, J and Manley, M. 2004. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. XXIInd International Conference on Polyphenols, 24-28 August, Helsinki, Finland.
11. De Beer, D, Joubert, E, Van Schalkwyk, D, Marais, J and Manley, M. 2004. Contribution of phenolic compounds to the total antioxidant capacity of Pinotage wine. 28th National Congress of the South African Society for Enology and Viticulture. 19 November, Cape Town, South Africa.

Final report
http://www.sawislibrary.co.za/dbtextimages/FinalReport121.pdf

Marais, J, Malan, J. 1999. Effek van gistingstemperatuur op Pinotage wynsamestelling en kwaliteit. Wynboer. Mnth Jul p. T11-12

Article

Marais, J. 1999. Pinotage navorsing. Wynboer. Mnth Feb p. T13-15

Marais, J, Truter, B. 2000. Effek van houtveroudering, swaweldioksied-vlakke en appelmelksuurgisting op Pinotage wynsamestelling en kwaliteit. WineLand. Mnth Apr p. 97-99

Marais, J. 2001. Exploring the relationship between Pinotage grape colour and wine quality. Wynboer. Mnth Feb n. 139 p. 76-78

Waldner, M, Marais, J. 2002. Impact aroma components in South African red wines: a preliminary study. WineLand. Mnth Dec p. 85-87

Marais, J. 2003. Effect of different winemaking techniques on the composition and quality of Pinotage wine. Part I. Low-temperature skin contact prior to fermentation. South African Journal of Enology + Viticulture. v. 24 n. 2 p. 70-75

Marais, J. 2003. Effect of different winemaking techniques on the composition and quality of Pinotage wine. Part II. Juice - skin mixing practices. South African Journal of Enology + Viticulture. v. 24 n. 2 p. 76-79

Marais, J. 2003. Lae temperatuur dopkontak voor gisting. 'n Tegniek vir die bereiding van hoë kwaliteit Pinotage wyne. WineLand. Mnth May p. 82-83

Marais, J. 2003. Mengtegnieke van sap en doppe tydens Pinotage wynbereiding. WineLand. Mnth Jun p. 81-83

Marais, J. 2003. Literatuuroorsig oor Pinotage navorsing. WineLand. Mnth Dec p. 75-77

Rossouw, M, Marais, J. 2003. Phenolic compounds in South African red wines: A preliminary study. WineLand. Mnth Feb n. 163 p. 77-79

Rossouw, M, Marais, J. 2003. Pinotage polyphenol profile. WineLand. Mnth Nov n. 172 p. 113-115

Marais, J, Jolly, N P. 2004. Pinotage aroma wheel. WineLand. Mnth Sep p. 113-114

Marais, J. 2004. The contribution of ß-damascenone to the berry-like aroma of red wines. WineLand. Mnth Jul n. 180 p. 93-95

Marais, J. 2004. The contribution of ß-damascenone to the berry-like aroma of red wines. Wynboer Technical Yearbook. p. 102-104

Rossouw, M, Marais, J. 2004. The phenolic composition of South African Pinotage, Shiraz and Cabernet Sauvignon wines. South African Journal of Enology + Viticulture. v. 25 n. 2 p. 94-104

Marais, J, October, F. 2005. Verband tussen druifkleur en wynkwaliteit. WineLand. Mnth Jul p. 85-87

Marais, J. 2004. Effect of low-temperature, prefermentation skin contact and mixing techniques during fermentation of Pinotage wine composition and quality. IN: Intervitis Interfructa 2004. 7th International Symposium on Innovations in Enology, Stuttgart, Germany, 10-11 May 2004. p. 91-101

Chapter

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