February (No. 493)
Hybrid wine yeasts, offering the winemaker a unique fermentation tool
Dr P. van Rensburg , Department of Viticulture and Oenology, Institute for Wine Biotechnology, University of Stellenbosch, South Africa
While the old saying, “the best wines are made in the vineyard”, is still valid, oenologists have also come to recognise the important contribution that specific Saccharomyces cerevisiae starter culture strains make to the type and style of a product. With the importance of S. cerevisiae’s role in winemaking now firmly established, there is an ever-growing demand for new and improved wine yeast strains. In addition to the primary role of wine yeast to catalyse the efficient and complete conversion of grape sugars to alcohol without the development of off-flavours, wine yeast strains must now also possess a range of other properties. Currently, there is a need for S. cerevisiae strains that are better adapted to the different wine-producing regions of the world, with their respective grape varietals, viticultural practices, winemaking and fermentation techniques.
This article will review the role that yeast selection and breeding programs, at different Institutions in South Africa, played in providing South Africa’s wine industry with a selection of unique yeasts and fermentation capabilities and how new technologies will be developed and used to further the potential of our repertoire of yeasts to make our industry more competitive.
There are three different options available that can be used to obtain new yeast strains. First, yeast strains can be obtained by means of a yeast selection program. Second, new yeasts can be obtained through a dedicated breeding program and, third, new yeasts can be obtained by means of the genetic engineering of existing strains.
NOTE: The complete article can be found in the February issue of The Australian & New Zealand Grapegrower & Winemaker.