Alternative use of wine grapes: Utilisation of non-Saccharomyces yeast for the production of balsamic-styled vinegar

Project Number
WW 10-24

Project title
Alternative use of wine grapes: Utilisation of non-Saccharomyces yeast for the production of balsamic-styled vinegar

Project leader
Jolly, N P

Team members
Jolly, N P
Du Plessis, H
Ohlson, S
Van Breda, V
Hoff, V
Adonis, P
Mas, A
Chidi, S

Project description
The South African wine industry is often perceived as elitist and lagging in upliftment programmes. There is also a perception that there is a lack of transformation within the industry. Grape producers are also being adversely affected by the global recession, over-production world-wide and anti-alcohol groups. Alternative options for use of grapes are also lacking. This project proposes an alternative outlet for wine grape producers by developing technology for the production Balsamic-styled vinegar by small entrepreneurial businesses.

Economic factors and global recession has led to decreased wine consumption and, in some instances, less exports of local wines. This has adversely affected the South African grape producer. In addition, the wine industry is under pressure from anti-alcohol legislation and a perception of a lack in transformation and empowerment in certain sectors of society. Global warming will also lead to some viticultural areas being unable to produce premium quality wines at consumer acceptable alcohol levels. Over-production is also a constant threat. With aforementioned in mind it is critical that an alternative use is found for wine grapes and that entrepreneurial opportunities are identified. Production of Balsamic-styled vinegar can serve both purposes. Grapes can be channelled to an alternative high-priced product, while necessitating low technological inputs, making it easy for a low capital start-up business.

Traditional Balsamic Vinegar (Aceto Balsamico Tradizionale) is an international regulated name (Italian Denominazione di Origine Protetta and the European Union’s Protected Designation of Origin). It differs from normal wine vinegar in that it is a primary product from grape juice and not a by-product or downstream product of wine. Traditionally Balsamic vinegar is made from cooked Trebbiano grape juice by a natural fermentation process in a solera styled system of barrels. The process can take up to 12 years. Balsamic Vinegar of Modena (Aceto Balsamico di Modena) is a more modern product made on industrial scale that ranges in quality and price.

Balsamic and balsamic-styled vinegars are high quality products that can command premium prices (e.g. 100 Euro/100 mL). True Balsamic vinegar production utilises yeasts (specifically non-Saccharomyces yeast) in conjunction with acetic acid bacteria for production and should not be wine vinegar sweetened with grape must. The initial yeast fermentation is critical to the formation of flavour compounds and complex volatile acids other than acetic acid, before the acetic acid bacteria complete the production process.

The nature of vinegar is such that a wine cellar cannot be used to make vinegar and a separate facility would be required. However, basic equipment (e.g. plastic food grade buckets) could be used for production without the use of cooling. This makes it an ideal venture for a small business with minimal capital outlay.

The yeast choice and acetic acid bacteria selections needs to be investigated, while a small-scale production process will have to be devised. The ARC has an extensive non-Saccharomyces yeast collection that can be screened for yeasts with desirable characteristics. Contact has already been made with a potential Spanish collaborator that has done research on acetic acid bacteria and forms part of a European Balsamic Vinegar project. This will dispense with the need for some aspects of basic research, while the required expertise can be tapped into. The Spanish collaborator is also willing to supply acetic acid bacteria (Acetobacter and Gluconacetobacter spp.) as their research has shown a succession of species during production is desirable. The isolation of South African strains and purchase of strains from international culture collections will also be looked at.

The project will be funded by DAFF (Department of Forestry and Fisheries), the evaluation of the project will be done by the Winetech Vinification committee.

FinalReport.pdf

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