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Wednesday, 20 April 2011 14:12

TechTalk: Photopurification of wine with UV Technology

A Swiss technology using ultra violet light energy for liquid purification in wine making, known as photopurification technology is gaining momentum, with many winemakers having used the system from a company called SurePure, resulting in less harmful chemical intervention and decreasing the need to add sulphur and other disinfectant additives, making it a potential alternative for wine purification in India as well.

Developed primarily for the dairy and fruit juice industry, it has found recent use in beer and wine industry as well. For the first time in the history of brewing industry, SAB has used this UV photo-sterilisation technology that uses light instead of heat to purify the raw ingredients for its alcoholic fruit juices and beverages. According to the company, SAB has already achieved 82% in energy savings over the previous pasteurization process and is looking for a potential savings of 94%. It offers solutions to common micro-biological problems in the cellar. The micro biological process results in reduction of sulphur, helps reduce pinking of white wines, reduces the problem of Bretts infestation and helps in avoiding problems related due to stuck fermentation. The process differs from the traditional wine filtration methods in that it replaces, or can act as an adjunct to many other common processes. It can replace sterile filtration, which strips colour and flavour from wine and can add significantly to wine loss. Photopurification also allows for less chemical intervention, either with sulphur, or other substances such as di-methyl-di-carbonate (DMDC). This also has a positive impact on the environment. According to the company, focusing on reducing sulphur content also serves to ensure a more sustainable and less environmentally invasive approach to wine-making. The technology is finding many users experimenting with it recently and already showing positive results according to a report. Johan Jordaan, Winemaker at Spier Wines in South Africa, has used the technology in 2009 and 2010 vintages. “Initially I had used the technology to treat wines that suffered from stuck fermentations prior to restarting them,” he says reportedly. “This wine was passed through the SurePure unit once and without being filtered. The VA (volatile acidity) of this wine was stable and after the successful re-ferment, the wine had no sluggish or stuck ferment smells. I have also used it to stop the fermentation of a Rose to have a higher residual sugar.” Jordaan believes that there is a place for the SurePure technology in the market and that you can produce outstanding wines with low sulphur, provided that you follow the fundamental rules of chemistry to preserve your wines. “I would think that low sulphur whites should be drunk very young or sealed with screw cap to preserve the freshness, whereas the reds can be stretched, provided that you have ample extract in the form of tannin to help preserve the wine against oxidation,” Jordaan says. The company which is poised to get the FDA approval for dairy products in the US makes several claims like extended shelf life, reduced water and energy requirements, preserving the sensory, chemical and phenolic integrity of wine and reduced need for preservatives like Sulphur because of its proven micro-biological efficacy. For details check out their website. The Indian wine industry faced with micro-biological problems and using excess sulphur to keep the liquid disinfected could well benefit from the new technology, especially as most of the wines are meant to be drunk young, with increasing focus on the use of screwcaps by the wineries of Maharashtra and Karnataka. Subhash Arora