Dealcoholization
Dealcoholization refers to the removal of alcohol from mostly drinks .
Procedure
Simple distillation is ruled out as a dealcoholization process for beverages, as the associated high temperatures damage the aromatic substances and change the taste of the beverage. In practice, in addition to having reverse osmosis and dialysis also the vacuum rectification enforced.
Reverse osmosis: it is possible for water and alcohol to diffuse through the membrane ( permeate ), the remaining components remain in front of the membrane ( retentate ). The permeate is freed from alcohol with the aid of distillation and then brought back together with the retentate. The components of the product that could be damaged by heating, which would result in a reduction in the quality of the wine, remain in the retentate and are thus protected from it, which is why the product quality is preserved, especially with this process.
Vacuum rectification: By lowering the air pressure, the boiling point of the alcohol is brought to 25–30 ° C (at around 15 mbar). This largely preserves the flavoring substances. In the case of wine , the alcohol is removed in several steps, in the end an alcohol content of less than 0.25% by volume usually remains, so that it can be described as alcohol-free under German law (up to 0.5% by volume). The alcohol content at this concentration corresponds to that of fruit juices and is below that of kefir or some types of pastry . At the end, sugar or grape must is added to the wine as a flavor carrier. This leads to renewed alcohol formation from the 0.02-0.05% by volume achieved by the method to the above-mentioned 0.1-0.25% by volume.