Pressure-based wine preservative
Sulfur oxides (SO2 and SO3), known as sulfites, are preservatives widely used in winemaking. While harmless to about 99 % of people, sulfites can cause an allergic response in asthmatics and other sensitive individuals. The EU-funded PRESERVEWINE-DEMO (Demonstration of a non-thermal process to replace use of sulphites and other chemical preservatives in European wines to meet new European directive) project developed an alternative to sulfite use in wine. The consortium is the successor to an earlier EU project, PRESERVEWINE. The new venture was intended to commercialise the previous project’s innovations. The prototype system reduced the need for chemical preservatives by quickly applying and releasing pressure up to 500 bar. The process treats the liquid and gas in the system’s hoses. The method, called pressure change technology, has been designed and validated at 120 litres/hour. Other components include a static mixing device, retention in a flow reactor and rapid release at a special valve. Researchers studied the effects of variables such as gas type, gas/liquid ratio, the depressurisation system and retention time. Pressurisation was shown to destroy spoilage-causing organisms. The process also dramatically reduced the wine’s dissolved oxygen, which protected against oxidation immediately after treatment and during storage in both barrels and bottles. Unlike heat pasteurisation alternatives, the project’s method did not change the wine’s colour, taste or smell. To qualify under the European Pressure Equipment Directive, the system must be simple and easy to clean, which remains a challenge for PRESERVEWINE-DEMO. The team designed an industrial-scale unit, to be built using a manufacturing process enabling economies of scale. Researchers plan to continue demonstrating the unit after the project’s conclusion, to confirm viability. Dissemination work included numerous press releases and articles, and also conference or industry presentations. Project staff identified sizeable market opportunities and numerous potential customers. To gain acceptance and validation by European wine authorities, the team must still brief winery operators and other stakeholders. PRESERVEWINE-DEMO’s work will mean a reduction in the use of sulfite preservative in wine. The product will be safer for people prone to allergic reactions.
Keywords
Wine, preservative, sulfites, dissolved oxygen, PRESERVEWINE-DEMO, non-thermal process
