Clearing the haze for white wine makers

Hazy white wines are a sure-fire way to turn consumers away. Whether it’s sauvignon blanc, semillon or chardonnay, most consumers prefer their favourite white to have a clean, clear sparkle. If white wines look cloudy it is a sign of protein instability and most consumers will presume it is faulty.

Research led by the Australian Wine Research Institute (AWRI) in partnership with the University of South Australia is ensuring white wines will always look their best using a novel magnetic nanotechnology that is designed to quickly and efficiently remove haze-forming proteins in white wine.

Funded by Wine Australia, the research combines AWRI wine research with the capabilities in surface nanoengineering developed at UniSA’s Future Industries Institute.

Lead researcher Dr Agnieszka Mierczynska-Vasilev said the technology shows promise as a sustainable alternative to conventional bentonite fining treatments, potentially saving the wine industry millions.

“Protein haze is a serious problem for the wine industry. Not only because consumers see it as a defect, but also because conventional bentonite treatments can cause significant wine volume loss, which is also reflected in the bottom line,” Mierczynska-Vasilev said.

“In Australia, the overall estimate of loss caused by bentonite fining is around $100 million annually, and globally, this equates to approximately $1 billion per year.

“Winemakers traditionally use bentonite to remove proteins and prevent haze formation, but as it is a clay, it swells in the wine solution and can lead to a loss of wine volume of approximately 3%.

“Using this technology, winemakers could potentially remove haze-forming proteins safely and efficiently, without bentonite-associated volume loss, and importantly, could do so multiple times with the same nanoparticles.”

The technology uses magnetic nanoparticles coated with acrylic acid polymers which, when placed in heat-unstable wine, attract and bind proteins to the nanoparticles’ surfaces. The particles are then drawn from the wine using a magnet, leaving behind a clarified product devoid of haze.

Tested on unfined* 2017 sauvignon blanc, semillon and chardonnay from South Australia, researchers found that the magnetic nanotechnology successfully removed 98% of haze-forming proteins from wines in 10 consecutive adsorption-desorption cycles, clearly indicating its ability for re-use.

“Unlike bentonite, a defining feature of this nanotechnology is its ability to be regenerated for re-application, without any adverse effects on the wine’s colour, aroma and texture compounds,” Mierczynska-Vasilev said.

“While there is still some way to go before the technology can be practically applied in wineries, and the need to obtain regulatory approval both in Australia and overseas, given the clear economic, sustainable and sensory benefits, this nanotechnology has a very strong potential for adoption — it’s absolutely a ‘watch this space’.”

*unfined: unclarified by filtration.

Image credit: ©stock.adobe.com/au/Subbotina Anna