The use of wild yeasts to complement wine aroma and broaden the spectrum of South African wine styles

Project Number
WW 10-08

Project title
The use of wild yeasts to complement wine aroma and broaden the spectrum of South African wine styles

Project leader
Jolly, N P

Team members
Bergstedt, J
Farmer, J

Project description
During the 1997 and 1998 non-Saccharomyces biodiversity studies, it was found that four non-Saccharomyces strains dominated in Chardonnay grape must prior to the onset of fermentation. They were Kloeckera apiculata, Candida stellata, C. pulcherrima and Torulaspora delbrueckii (C. colliculosa). As dominant strains, their contribution to the wine fermentation could be expected to be greater than the strains present in lower numbers. Their effect on wine quality was investigated during small-scale winemaking trials. From the data obtained it was evident that for each cultivar investigated, a different non-Saccharomyces – Saccharomyces combination gave the best wines. During the 2001 harvest the combinations of non-Saccharomyces – Saccharomyces was expanded. The results of the winemaking trails will be available during the next report year.

Further investigations on the influence of non-Saccharomyces yeasts in wine fermentation showed that some could be detected up to the ninth day of fermentation. However, they did not adversely affect the fermentation of higher Balling musts. A separate investigation showed that during fermentation K. apiculata could be found more readily in certain areas of a fermentation vessel i.e. foam and vessel surface than the S. cerevisiae. This aspect will be investigated further.

Selected non-Saccharomyces yeasts were found to play a role in the levels of volatile acidity and urea in wine. However, this was influenced by winemaking style and media composition, respectively. Non-Saccharomyces yeasts were also screened for utilisation as bio-control agents. Promising results were obtained and are reported elsewhere.

The second part of the project, dealing with non-Saccharomyces yeast bio-diversity was concluded with a more in depth investigation of the appearance of K. apiculata in the Robertson area. It was concluded that K. apiculata while present in the wider Robertson area, is not found in one specific vineyard. Kloeckera apiculata is also not dominant in most of the sites investigated in the Western Cape.

Poster(s)
Jolly, N P. 1995. The role of non-Saccharomyces cerevisiae yeast strains in wine fermentation. Poster presented at the 1st International Congress of the South African Society for Enology and Viticulture. 8-10 November, Cape Town, South Africa.

Jolly, N P. 1996. The use of non-Saccharomyces cerevisiae yeast strains in wine production. Poster presented at the 9th Congress of the South African Society for Microbiology. 8-10 July, Pretoria, South Africa.

Jolly, N P. 1997. The use of non-traditional yeast in sequential fermentation for wine production. Poster presented at the 18th International Specialised Symposium on Yeast. 24-29 August, Bled, Slovenia.

Jolly, N P. 1997. The use of non-traditional yeast in sequential fermentation for wine production. Poster presented at the 21st National Congress of the South African Society for Enology and Viticulture. 27-28 November, Cape Town, South Africa.

Jolly, N P and Pretorius, I S. 2000. The distribution of non-Saccharomyces cerevisiae yeast strains in four production regions of the Western Cape, South Africa. Poster presented at the BioY2K Combined Millennium Meeting. 23-28 January, Grahamstown, South Africa.

Jolly, N P and Pretorius, I S. 2000. The distribution of non-Saccharomyces cerevisiae yeast strains in four production areas of the Western Cape, South Africa. Poster presented at the 2nd International Congress of the South African Society for Enology and Viticulture. 8-10 November, Cape Town. South Africa.

Bergstedt, J, Lambrechts, M G, Jolly, N P and Du Toit, M. 2001. The influence of non-Saccharomyces cerevisiae yeast strains on volatile acidity in wines. Poster presented at the 25th National Congress of the South African Society for Enology and Viticulture. 15-16 November, Cape Town. South Africa.

Jolly, N P and Pretorius, I S. 2002. The use of Candida pulcherrima in combination with Saccharomyces cerevisiae for wine production. Poster presented at the 22nd International Specialised Symposium on Yeasts. 25-28 March, Pilanesberg National Park, South Africa.

Jolly, N P and Pretorius, I S. 2002. The use of Candida pulcherrima in combination with Saccharomyces cerevisiae for wine production. Poster presented at the 26th National Congress of the South African Society for Enology and Viticulture. 13-15 November, Cape Town, South Africa.

Presentation(s)
Jolly, N P. 1996. The role of non-Saccharomyces cerevisiae in wine fermentation. Presentation at the ARC Infruitec-Nietvoorbij Enology Short Course. 3-4 October, Stellenbosch, South Africa.

Jolly, N P. 1997. The presence of non-Saccharomyces cerevisiae yeast strains during wine fermentation. Presentation to the Independent Winemakers’ Guild. 20 January, Vergelegen, Somerset West, South Africa.

Jolly, N P and Pretorius, I S. 1999. The distribution of non-Saccharomyces cerevisiae yeast strains in four production areas of the Western Cape. Paper presented at the 23rd National Congress of the South African Society for Enology and Viticulture. 12-13 November, Cape Town, South Africa.

Jolly, N P and Pretorius, I S. 2000. The distribution of non-Saccharomyces cerevisiae yeast strains in four production areas of the Western Cape, South Africa. Paper presented at the 10th International Symposium on Yeast. 27 August – 1 September 2000, Papendal, Arnhem, The Netherlands.

Jolly, N P. 2000. The influence of non-Saccharomyces cerevisiae yeast strains on wine fermentation. Paper presented at the 2nd International Congress of the South African Society for Enology and Viticulture. 8-10 November, Cape Town. South Africa.

Jolly, N P. 2004. Characterisation, evaluation and use of non-Saccharomyces yeast strains isolated from vineyards and must. Presentation to Forschungsanstalt Geisenheim. 14 May, Geisenheim, Germany.

Article
Strauss, M L A, Jolly, N P, Lambrechts, M G, Van Rensburg, P. 2001. Screening for the production of extracellular hydrolytic enzymes by non-Saccharomyces wine yeasts, Journal of Applied Microbiology, v. 91 (1) (p. 182-190)

Jolly, N P, Augustyn, O P H, Pretorius, I S. 2003. The occurrence of non-Saccharomyces cerevisiae yeast species over three vintages in four vineyards and grape musts from four production regions of the Western Cape, South Africa, South African Journal of Enology and Viticulture, v. 24 (2) (p. 35-42)

Jolly, N P, Augustyn, O P H, Pretorius, I S. 2003. The effect of non-Saccharomyces yeasts on fermentation and wine quality, South African Journal of Enology and Viticulture, v. 24 (2) (p. 55-62)

Jolly, N P, Augustyn, O P H, Pretorius, I S. 2003. The use of Candida pulcherrima in combination with Saccharomyces cerevisiae for the production of Chenin blanc wine, South African Journal of Enology and Viticulture, v. 24 (2) (p. 63-69)

Jolly, N P, Augustyn, O P H, Pretorius, I S. 2006. The role and use of non-Saccharomyces yeasts in wine production, South African Journal of Enology and Viticulture, v. 27 (1) (p. 15-39)
Article.pdf

Jolly, N P. 2006. The occurrence of apiculate yeasts in grape and must samples from the Robertson area, WineLand, Mnth May (p. 68-70)

FinalReport.pdf

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