Turning a waste left over from the wine-making process into a sustainable industry is the aim of new University of Adelaide wine research at the Waite campus.
The researchers are looking at ways of improving the processing of grape marc ─ the solid waste left after crushing the juice from grapes ─ for increased alcohol production for use in spirits such as brandy, and for fortifying wines.
“The amount of red and white grape marc produced (including skins, stalks, and seeds) depends on the size of the winery and wine-making technologies used, but nationally its estimated that several hundred thousand tonnes is generated every year,” says Dr Ravichandra Potumarthi, Post-doctoral Research Associate with the University’s new Australian Research Council (ARC) Training Centre for Innovative Wine Production. “It’s around 15-30 per cent of the weight of the grapes used for wine-making and disposal poses a problem for the industry.
“Grape marc can be used to generate revenue from recovered alcohol through further processing of the waste and distillation. But current process methods need to be more efficient for wide-spread adoption by the industry. Our research is aimed at developing sustainable technology and processes that will help the wine industry generate more revenue and make better use of this by-product.”
Dr Potumarthi is a bioprocess/chemical engineer by training with more than 13 years’ experience in industrial and environmental biotechnology for process development.
He is working with wine science senior lecturer Dr David Jeffery and industry partners to investigate alternate fermentation methods, process optimisation and pre-treatment techniques. He is also undertaking a cost-benefit analysis of the processes involved, and assessing how alcohol yield and quality can be improved.
“I’m looking to see how to produce more alcohol from the same amount of grape marc through more efficient processes, and also developing new ones.
“If we can enhance processing efficiencies for alcohol production, producers will be able to generate more revenue from the same amount of grapes; converting a waste stream into a valued product,” Dr Potumarthi says. “In this way the wine industry will be able to address environmental concerns of waste disposal and make their industry more sustainable.”
The ARC Training Centre for Innovative Wine Production was officially launched in May. Supported by the ARC and 12 partner organisations, the centre aims to build knowledge and technologies that will help the wine industry face the challenges of climate warming, water limitations, changing consumer preferences and increasing production costs.