Ξ April 26th, 2012 | → 14 Comments | ∇ A Day at a Time, Technology, Wine News |
Just when it seemed the debate over the use of sulfites in wine couldn’t get any more acrimonious, along comes a promising new technology which threatens to bring peace.
Though dried fruits typically contain 10 times the sulphur dioxide (SO2) found in wine and SO2 levels in fruit juices frequently equal or exceed it, our most holy fermented grape juice remains a special case. After all, no one spends $10,000 on a bottle of fruit juice unless it is fermented. Now, whether conventional, sustainable, organic, biodynamic, or ‘natural’, winemaking employs sulfites on a sliding scale, driven in large measure by health concerns, both of the body (at high levels sulphur can have deleterious health effects) and of the planet (sulphur is a petrochemical product). Or perhaps I should say by the perceived dual health concerns. As often as an expression of an earnest environmentalism, bad faith, opportunistic and commercial, informs the choice, the position a winery, a critic or consumer may take on the use of sulfites and SO2. Why bad faith? Well, let’s just say that neither a natural wine booster traveling 5000 miles through the ionized upper-troposphere to a tasting, or an industrial winemaker re-wiring his pesticide sprayer to run on solar-charged batteries are models of consistency.
But were I writing a website dedicated not to the wine industry but to that of dried fruits and juices, not to mention dehydrated potatoes, vegetables or even pancake syrups, I should likely have a post or two dedicated to this nearly omnipresent preservative. And I would just as likely be discussing this new technology.
It is called Pressure Change Technology (PCT) and was, as near as I can determine, first presented in the pages of a scientific journal, Chemical Engineering & Technology from 2007 (subscription only). Titled The Effect of a New Pressure Change Technology (PCT) on Microorganisms: An Innovate (sic) Concept for Food Safety, the abstract reads,
“A new pressure change technology (PCT) for a non-thermal inactivation of microorganisms in liquid food and pharmaceuticals is described. This technology was applied to food-relevant microorganisms and was capable of reducing the organisms up to 7.5?log. The influence of process parameters (type of gas, pressure, and temperature) was investigated with the help of physiological changes of microorganisms. The results of this pressure change technology are shown and discussed.”
Just thank the lord I am not discussing that paper. A more layman-friendly press release from the Internet Journal of Viticulture and Enology caught my eye last week.
“Pressure Change Technology (PCT) is a low cost process with minimum energy use that has potential with further development and validation to be of significant commercial benefit to wine producers by providing them an alternative to the use of sulphur dioxide in the winemaking process.”
The company referenced in the full press release is PreserveWine. From their site,
“PCT is a novel non-thermal technique that involves charging a liquid product with pressure and an inert gas [N and Ar - Admin] and then rapidly releasing the pressure. The sudden pressure release causes microbial cell walls to rupture, inactivating microorganisms. This has been demonstrated on a small pilot scale batch process; in the current project PreserveWine the PCT process will scientifically validated. A further objective is the development and scale-up into a continuous in-line pre-industrial demonstrator to test the PCT with wine and other liquid foods.”
The objectives to be achieved are the following,
- Repeated validation of the process to reduce microbial loading in wine by at least log10 5 and protect wine from chemical and biological oxidation.
– Enhanced organoleptic quality (aroma and taste) of wine when compared to ’sulphited wine’ wines when assed by a trained taste panel.
– Pilot scale demonstration of our PCT system capable of being integrated into a commercial winemaking process line, at flexible design for optional application at various processing stages, with a throughput of 120 L/h
– Full HACCP and GMP compliance
– Provide data to scale up to industrial capacity of 1.2 m3/h at energy costs of 40% to comparable thermal processes, ensuring a potential market share of 1% of the wine holdings in Europe.”
Two wineries have been the site of preliminary research: Château Guiraud, a well known French producer of fine sweet wines located in Sauternes, a short distance from Bordeaux; and Tenute Del Vallarino, a producer of still and sparkling wines in the Piedmont region of Italy. As is well known, SO2 acts in wine as both an anti-microbial – ‘bound’ sulphur – and a color preservative – ‘free’ sulphur – for white wines. ‘Bound’ sulphur inhibits bacterial growth, while ‘free’ sulphur reacts with oxygen to prevent oxidation. One can easily understand Château Guiraud’s concern, inasmuch as sweet wines contain very high amounts of sulphur. Tenute Del Vallarino produces white wines.
The project was begun in December, 2010 and results will be published on November 30th of this year, 2012.
Many questions remain unanswered, of course. Though PCT is scaleable and is said to both low in cost and energy use, whether this new technology will be embraced by wine purists, or endorsed by Demeter and from within the organic wine movement, remains to be seen. Personally, I wish PreserveWine great success.
Ken Payton, Admin
For further reading:
— See the very detailed PDF. It includes photos and diagrams of the process. Allergens In Wine: What Lies Ahead?
— New EU rules for ‘Organic Wine’ agreed
— Do EU organic rules for wine leave glass half empty?
— Sulphites in wine