Reverse osmosis is a pressure-driven membrane separation process. In the dealcoholisation of fermented beverages, water, ethanol and other small molecules in particular pass through a semipermeable membrane, while many larger components remain concentrated in the retentate.

The alcohol-containing permeate is subsequently processed further. Suitable alcohol-free or low-alcohol fractions can then be recombined with the retentate.

The aim is to reduce the alcohol content while preserving the original sensory characteristics of the beverage as far as possible.