Electrodialysis with Bipolar Membranes (Bipolar ED) reduces the pH of wine, grape must, and grape juice without adding acids or using ion exchange resins.

Developed by Eurodia Industrie in France, Bipolar ED reduces pH of wines by 0.1 to 0.5 pH units, and juice by 0.3 to 0.8 pH units. The acidity is generated by a unique water-splitting process that occurs inside the bipolar membrane. Bipolar membranes split water into H+ and OH- ions. The wine is acidified by the H+, and potassium is transported across a cation-transfer membrane. pH reduction using Bipolar ED preserves the integrity of the products since nothing is added to the wine. There is no loss of product.

Bipolar ED dramatically reduces water consumption and high-salt effluent produced during the acidification of wine or juice with ion exchange resins. Once removed, the potassium combines with the OH- from the water splitting reaction. The KOH stream, at a pH of 12, is concentrated using an RO based recycling system. The concentrated effluent is ideal for cleaning winery equipment, or may be re-used in other industries.