22 February 2007 Summer project sets direction for wine haze research

 

A Lincoln University summer scholarship has developed new protocols for characterizing the hazes that can form in wines, opening the way for further work to explain the process of haze formation.

Under the supervision of Dr Roland Harrison, summer scholar Lyndon Greening established a set of protocols of haze collection by three methods, based initially on an assessment of a batch of unfined Chardonnay provided by Pernod Ricard NZ in Marlborough.  These methods were also applied to a range of fined and unfined Sauvignon blanc wines from five Marlborough vineyards following a Marlborough Wine Research Centre trial looking at the relationship between irrigation levels and rates of bentonite fining.

“Initial results suggest fined wines reduced the quantity of haze formed and haziness as measured by nephelometry, compared to unfined wines,” says Dr Harrison.  “There were also some differences between vineyards and pruning methods which demand further inquiry.”

Dr Harrison says the next phase of the research is to introduce another method of haze collection and characterisation, using capillary electrophoresis (CE), and to investigate the effects of various reagents to disperse haze components.  Arrangements have been made with Marlborough Wine Research Centre in preparation for this to begin.   

Haze in wine is a significant issue for the industry. The most frequent cause is protein-polyphenol interaction.  Although a clear wine can be achieved relatively easily by fining and filtration, the problem for the producer is to ensure that the product remains ‘brilliantly’ clear for a reasonable period (say, four or five years).  In white wines, this is usually achieved by carrying out fining trials to determine the level of bentonite to prevent a haze from forming.  Often, and particularly with Sauvignon blanc, standard tests indicate much greater levels of bentonite than the winemaker feels  is desirable, because of the effect on varietal-character and the volume of sediment

Lyndon Greening is the latest in a series of postgraduate students from Lincoln University to be awarded a summer scholarship, which aim to address specific questions with direct application to industry.   Lyndon has completed Honours in Viticulture and Oenology and recently accepted a position with Nelson-based Siefried Estate.

Dr Harrison says the work has attracted significant interest from within the industry and has been picked up as a new PhD study in association with Pernod Ricard and the Marlborough Wine Research Centre.

“These summer scholarships typically involve a short, sharp research project in an area that can resolve a current problem or establish the basis for a more detailed research programme.

“Summer scholarships are popular with students intending to take a career path into research, but are also useful for students to gain experience and a competitive edge in the market for new graduates.

“Graduates with this kind of experience are very much in demand.”

Lincoln University’s Food and Wine Group is New Zealand’s major provider of multi-disciplinary research and teaching for the wine industry.   The Group has established collaborations campus-wide, including commerce, marketing, tourism studies, ecology, soil science, plant physiology and molecular biology.

 

Elizabeth Owens, Marketing and Communications Manager, Lincoln University, Canterbury