Project title
Optimisation of wood flavourants for the production of quality wines through improved wood production strategies, with special emphasis on alternative wood products

Project leader
Rypstra, T

Institution
University of Stellenbosch

Team members
Swart, J

Project description
Currently, the use of alternative wood products such as staves, chips, powder and wood extracts, to provide oak fragrance in winemaking, is in a developmental stage but is, because of its economic and technological benefits, rapidly gaining acceptance in the South African wine industry. As with barrels, a need exists to develop the use of these products i.e. the technologies, on a scientific basis. The objective of this project is to gain an insight into the present role of wood in winemaking by first verifying the current benchmark status of the standard oak barrel (wine in wood) and then to extrapolate this knowledge to alternative products (wood in wine). The findings of this report and deliverables of the first year of this project are based on direct communication with selected manufacturers and suppliers, and users of barrels/alternative products (winemakers), as well as the result from a literature survey.

The criteria whereby wine barrels are bought and sold in SA are in terms of material properties (species, provenance, grain, part and age of the tree, etc.) and processing properties (timber log breakdown, drying, barrel manufacture and toasting methods). The current criteria appear to work on the wine-maker/cooperage interface. However, the wine-maker?s flavour requirements in terms of chemical substances required from the wood are at best, indirectly specified in terms of physical wood properties. Because of the large number of complex and interrelated criteria, a need exists for more scientific, extensive and statistically acceptable information. The inevitable use of cooperage timbers from non-traditional provenances and regions requires scientific scrutiny and approval. Reliable techniques such as DNA tests reported in an EU sponsored study, are required to control the provenance of wood.

Serious need for transfer of existing knowledge on the role of wood in barrels and alternative products was expressed by individuals interviewed.

Some similar and different physical and processing parameters of the alternative products to barrels were identified confirming the existence of the specific alternative product technology. The geometry and shape, drying and toasting processes, wine/oak mass ratios, stage and duration of oak flavour addition, were considered. Limited scientific information on alternative products could be obtained from literature searches.

The use of wood alternative technologies can effectively be regarded as the addition of wood-borne (chemical) additives. The wording in Act 60 of 1989 as amended 7 March 2003 is written in such a way that it allows and encourages responsible experimentation with wood and tannins. The possibilities and limitations, and possible transgressions of the law, can only be debated on the basis of sound technical and scientific information.

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