Edecto, a German medical processing laboratory in Dresden, has developed a method to preserve wine without adding sulfur dioxide by utilizing pressure change technology. The process was first created to pasteurize fruit juice. After a small batch of both red and white wines was tested, scientists are claiming the results are promising.
Sulfur dioxide is a common additive used by winemakers during the fermentation stage to preserve the wine’s flavor, character, and color. The compound also naturally occurs at low levels during the process. Sulfur dioxide dissolves into sulfites, which can cause an allergic reaction that leads to asthma. Both antimicrobial and antioxidizing in nature, sulfur dioxide protects wine from spoiling by deactivating microorganisms during fermentation to prevent wine from turning into vinegar. Unwanted yeasts, acetic acid and lactic acid bacteria are destroyed. Sulfites also allow wine to be preserved for aging as they inhibit oxidation.
Other methods to sustain wine have been used without success, or in theory are not considered good preservation techniques because they destroy certain components in wine that make a particular vintage unique. Filtration has been used to some success but has its limits before color is altered and important taste components are removed. Pasteurization is not a viable option as high heat is required and valuable heat-sensitive elements are ruined.
The new pressure change technology technique is a form of “cold pasteurization” of liquid foods that operates on moderate temperatures. A chemically inert gas, such as nitrogen or argon, is dissolved at high pressure into the liquid. As pressure increases, so does the solubility of the gas, which diffuses into microbial cells. The pressure is then suddenly decreased, allowing gas within cells to expand and effectively make them burst, killing all microbes. The gas that was dissolved in the cells is recovered and then reused. The presence of inert gases also stabilizes the liquids by preventing oxidation reactions from occurring.
When the pressure change technology method was tested on red and white wines, taste was not affected while color remained intact after a certain aging period in both bottles and barrels. Another positive facet of the pressure change technology is that the process can be used during any time during the winemaking production.