FIELD: non-alcoholic or alcoholic beverage industry. SUBSTANCE: the process for selectively removing non-volatile substances from a non-alcoholic or alcoholic beverage or a sugar-containing solution comprises stepwise diaphragm separation by ultrafiltration and reverse osmosis into a permeate and retentate, removal of non-volatile substances such as sugar and/or acid, and/or an unpleasant-smelling substance, or conversion and use thereof in the final product, and the non-volatile substances are removed or converted from the retentate by using physical or chemical or biotechnological processes suitable for the separation of non-volatile substances, and the substances that remain after removal or conversion are at least partially once again subjected to conversion or become part of the final product. After removal and conversion of the substance, the permeate is at least partially returned to the retentate after diaphragm separation or to the recycled permeate which mounts a device for removal or conversion of a substance. The sugar that is contained in the permeate or retentate is converted by fermentation to an alcohol which is at least partially removed, and the permeate containing aromatic substances is once again added to the retentate or permeate. If ultrafiltration is employed, the separation boundary is 5000 Dalton, at maximum. When diaphragm separation is employed, the diaphragm is selected in such a manner that the permeate contains substances that should desirably be present in the final product, and the retentate contains substances to be removed or converted. Prior to stepwise drophragm separation, the beverage or solution is preliminarily separated according to a diaphragm separation procedure, and the resulting retentate is added to the retentate when diaphragm separation is employed, and the permeate is added afterwards. The preliminary separation boundary is below the diaphragm separation boundary and selected so that said boundary separation is within the reverse osmosis and ultrafiltration and boundary zone. This boundary is within the boundary zone of reverse osmosis and ultrafiltration. EFFECT: more efficient selective process. 17 cl, 3 dwg
