Swiss technology helps uncover oak’s secrets

Switzerland may not be renowned as a wine producer, but its mass spectrometric technology could help provide major benefits for winemakers.

Australian PhD student Ross Farrell recently spent 10 weeks at the Zurich University of Applied Science to apply specialised technology to the on-line analysis of the oak toasting process.

His goal is to develop new analytical methods for rapid assessment of oak wood chemistry to provide a direct measurement of oak sensory quality. If he succeeds, winemakers would be able to quickly and regularly source oak wood with known sensory characteristics.

“Current oak evaluation methods require time-consuming and labour intensive sampling procedures for expert, lab-based analysis,” he said.

“The lack of oak chemistry data results in identical seasoning and toasting protocols even though oak is known to vary greatly, among species and sites, and even between and within trees on the same site.

“The wine industry currently relies on subjective descriptions of oak quality that are inherently difficult to relate to wine quality impact.”

Mr Farrell’s studies at the University of Tasmania are supported by an AGWA Scholarship and an Australian Postgraduate Award, and he visited Switzerland with an AGWA (formerly GWRDC) travel grant.

The focus of his time in Zurich was on the real-time analysis of volatile compounds generated during the toasting of oak staves.

“Although the inherent oak chemistry and seasoning are important factors, the toasting process is widely regarded as the key stage in imparting the desired sensory characteristics to oak,” he said.

“By developing robust systems for real-time monitoring of oak aromas as the wood is toasted we hope to improve our understanding of the process and clarify previous research. This applies to both barrels and barrel alternatives.”

Prior research has shown that the different sizes of pieces used as alternatives to barrels and the different toasting methods applied to them means that the flavor profile of these alternatives is inconsistent when compared with traditional battle toasting methods.

The chemical composition of barrel alternatives varies greatly and has not been clearly related to quality. Given the increased use of barrel alternatives for certain wine styles, Mr Farrell believes there is great scope for improving quality control.

He was drawn to this project as a professional wood scientist with “an interest in flavours”.

He completed a Master of Science in Wood Science at the University of British Columbia in 2002 and has since worked in industry and academic roles in Australia and Canada. He is due to complete his PhD in 2016.





Ross working as a cellar hand at Tamar Ridge Estates during the 2012 vintage.
Ross working as a cellar hand at Tamar Ridge Estates during the 2012 vintage.