The Australian Research Council has funded a University of Adelaide project investigating a more efficient method of finishing wines, which could save the Australian wine industry tens of millions of dollars each year.
Professor Kerry Wilkinson. Credit: Isaac Freeman.
Led by the University's Professor Kerry Wilkinson, the research focuses on the clarification and stabilisation of wines - the processes that 'finish' wine to prevent undesirable physical or sensory changes from occurring between bottling and consumption.
Currently additives such as bentonite and activated carbon are used to remove wine constituents such as phenolic compounds responsible for astringency (harshness), bitterness, and browning, or volatile compounds that impart off odours and flavours which arise naturally or from spoilage or contamination and taint.
Fining agents like bentonite, which inevitably contribute to some loss of wine, are often not selective and may affect elements in wine that create the aroma and flavour that consumers enjoy.
"The use of bentonite and other fining processes can lead to 2-10 per cent of wine being lost in the process, costing the Australian wine industry around $100 million each year," Professor Wilkinson says.
"New methods that 'finish' wines rapidly, with higher recovery rates, and reduced waste and input costs are therefore needed."
Professor Wilkinson's project has been awarded $1,141,640 over four years, as part of the ARC's Mid-Career Industry Fellowships scheme, to investigate the potential winemaking applications of membrane filtration.
"I've been working with VAF Memstar on a range of membrane filtration related applications for some time, from dealcoholisation to smoke taint remediation," Professor Wilkinson says.
"It is apparent that membrane filtration offers a viable alternative for several stabilisation and clarification applications, particularly phenolic management. And we've made some good progress with protein stabilisation as well, but we haven't quite solved that one just yet."
When wine passes through membrane filtration, it fractionates, with larger molecules remaining on one side of the membrane and smaller molecules passing through.
Only a small amount of the wine constituents that create negative features in wine pass through the membrane, requiring less treatment with additives like bentonite, reducing the amount of wine lost in the process.
"Membrane filtration can also be used to transform wine made from heavy pressing fractions, which would ordinarily be too phenolic, bitter or astringent to be of commercial use, into wine of significantly improved quality," Professor Wilkinson says.
"So, in this way, the technology can improve production volume and value - again, without the use of additives."
VAF Memstar, a South Australian beverage filtration company, is a partner in this project, as is the Australian Wine Research Institute and Hill-Smith Family Estates, owner of iconic Barossan winery, Yalumba.
"Yalumba has a very strong commitment to decreased use of additives, so this project aligns strongly with their sustainability goals, and they will support the project through access to wine," Professor Wilkinson says.
"VAF Memstar will contribute the membrane technology and expertise in wine fractionation needed for this research, and Dr Keren Bindon from the Australian Wine Research Institute will provide complimentary expertise in wine analysis.
"The industry partners involved in this project are absolutely critical, the research simply wouldn't be possible without them, so I'm grateful for the opportunity to continue our collaboration."
