Wine without sulphur
Sulphur dioxide gives food products a longer shelf life, can however provoke unwanted effects, in particular in the case of allergy sufferers. In the framework of the "SO2SAY" research project, ttz Bremerhaven and its project partners developed a process for the stabilization of red wine which is not based on sulphur dioxide, but instead on natural extracts. Thus there is no need to state "Contains sulphites".
The use of sulphur dioxide (SO2) is common practice in the food industry. The SO2 extends the shelf life of products such as wine, potatoes or dried fruits. It prevents secondary fermentation and has an anti-oxidant effect, so that the enzymatic browning, as is seen with sliced apple, is reduced. But apart from these positive effects, the sulphurization of food products also hides dangers such as asthma attacks. Wine and food producers are desperately searching for alternatives, as even just one glass of wine or 10 mg of SO2 per litre can trigger an allergic attack.
Within SO2SAY, an EU-funded project, the partners developed a strategy to replace sulphur dioxide and its salts in food products, including wine. The challenges lie in achieving a comparable shelf life in food products which are free of sulphites and in avoiding changes in smell, taste and appearance. Corresponding storage tests will run until the spring of 2013.
Preservation with original wine extracts - "Contains no sulphites"
SO2SAY developed a process for the stabilization of red wine which dispenses as far as possible with sulphur dioxide. The objective is thus to preserve the sensory acceptance of the wine. In place of SO2, extracts, which occur naturally in wine, give it its shelf life. There can be up to 160 milligrams of sulphur dioxide per litre in commercial quality wines. The SO2SAY wine reduces this amount by over 95 percent. Allergy sufferers can therefore take a deep breath and enjoy their wine again. In addition, the percentage lies below the official detection threshold so that the wine counts as SO2-free and must not be labelled with "Contains sulphites". In the framework of the "clean label" discussion, the process is therefore particularly interesting for quality producers and demanding customers. The tasty prototype was produced under scientific supervision by Biurko Gorri, Spanish project partner and vineyard.
It's the taste that counts
Apart from price, taste is the main criterion for the (re)sale of a wine. In sensory tasting sessions with a representative number of testers in Great Britain, Spain and Germany, the new wine was judged as equally good in a comparison with high-quality reference wines. The wine was filled from the barrel into bottles in May 2012 and is currently continuing to mature there. At the next meeting of the nine project partners in January 2013, a few of the bottles were opened and put to the acid test. If the SO2SAY wine passes the final analytical tests four months later too, then from a technical standpoint nothing more will stand in the way of using the process. Product approval and the name under which the wine will be sold are currently being clarified by the partners.
Knowledge transfer from basic research to application
The SO2SAY project is a model example for the successful transfer of knowledge from basic research via applied research to application. Together with the Dutch University of Wageningen, ttz Bremerhaven identified a special plant extract which makes it possible to dispense almost completely with sulphur dioxide in wine, since this extract, which is a natural component of wine, fulfils the same purpose as the SO2: It has an antimicrobial, antioxidant and inactivating effect on enzymes, which means, amongst others, that the browning of the wine is prevented.
Nine partners from four European countries and Israel participated in SO2SAY. The EU-financed project (FP7) was coordinated by ttz Bremerhaven.
Source: ttz Bremerhaven