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How 'volatiles' affect wine – and what we can do about it

How chemistry could help create the perfect drop.

If you thought your taste buds were the most important thing in tasting wine, you’d be wrong. It’s all about your nose. Wine tasters aren’t swishing the wine around in their glass and plunging their noses in it for fun. We actually experience wine through its aromas. Receptors in the back of our nasal cavity detect and perceive much of the flavour.

But what impacts aroma? Aromas consist of small molecules, or volatiles, which readily change into a gas. Aroma active volatiles (those detectable by smell) impact on the sensory quality and experience of drinking wine. 

Aromas come from the grape and are affected by the climate and various viticultural treatments that can influence how much sunlight or shade the vine is exposed to, and ultimately the timing of harvest. 

Viticulturists test sugar and acidity levels in the grapes to help determine the best time to harvest grapes, but the general observation that sugar concentrations increase and acidity decreases with ripening has no physiological basis, and consequently many exceptions have been observed. Additionally, these measures provide no indication of the aromatic potential and current tools to address this issue are limited.

Ross Farrell is a PhD student in analytical chemistry at the University of Tasmania's Australian Centre for Research on Separation Science, and he is going to change that. He is adapting technology currently used by the security industry, to measure trace explosives, and the medical industry, to analyse biomarkers of disease in people’s breath, to analyse grape volatiles to help identify the optimal time to harvest grapes. 

“When you harvest grapes has a big impact on wine quality. But, there is currently a lack of objective measurement. I’m developing a grape-sniffer that allows the viticulturist to measure volatiles as soon as a grape is picked, in real time, to determine the best time to harvest grapes for optimal aroma.”

Ross is currently using a $1million instrument that processes mega amounts of information in real time. But he’s hoping to develop a tool that is affordable and easy to operate. 

Technology that used to be available only in a lab is becoming increasingly more obtainable and portable. Every winery could soon have their own portable mass spectrometer and they wouldn’t have to be an expert to use it.

By creating a decision support tool with this level of sophistication, viticulturists would have greater control of grape quality, more consistent quality of wine, less wastage, and ultimately more premium, higher value wine. 

“Aroma is the key selling point of wine. It provides the nuance and complexity. Most wine labels have a premium wine that has reached the highest quality possible from the vineyard, and table wines, from the same grapes, that did not. 

The technology that I am adapting would allow viticulturists to create greater quantities of premium wine, with smaller error bounds.

Ross has an MSc degree in wood science and engineering. His engineering background sparked his interest in the technology side of the project, but he really came to do his PhD because of his interest in flavours. 

“I met a researcher at the University of Tasmania, Rob Shelley, who convinced me that a PhD in analytical chemistry was the way to go. I’m glad I listened. There is something mysterious and hard to describe about aroma that I find really engaging.

I also didn’t realise that there was such a concentration of chemists regarded as being at the top of their field internationally right here in Tasmania.

“We have the international guru of chromatography, Professor Paul Haddad, and many others that are widely regarded among the top in their field anywhere on the planet.”

Ross said that he was nervous coming back to University as a mature age student.

“I didn’t need to be – I found really good people.”

Ross will submit his thesis at the end of 2016, and hopes to explore further research in this exciting field, and ultimately commercialise such technology in the wine industry.

“There are still multiple steps to getting this new technology developed and embraced by the wine industry. But strategic plans start with the strategic vision."

It’s amazing to be able to have access to the top technology on the planet, have all the benefits of living in a place as beautiful as Tasmania and still travel the world doing really exciting work.

About Ross Farrell

“My PhD research is focused on frontier analytical technologies and their application to wine industry quality control problems. 'Amara's Law' states that we tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. I believe that we can develop technological solutions to most problems, however, the key challenge is to balance complexity and cost with real-world practicality.”

Ross’s PhD is partially funded through a scholarship with Wine Australia. He is also the recipient of an Australian Endeavour Fellowship that saw him travel to the Swiss Federal Institute of Technology (ETH-Zurich), where he is still a guest researcher.

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