How Does Alcohol Reduction Work?

With the Memstar AC reverse osmosis and perstractive membrane process, wine alcohol is selectively reduced while flavours, colours and tannin are preserved.

The process is a “closed loop” with two membrane barriers between the wine being treated and the strip water which removes the alcohol. The actual alcohol stripping step is performed on reverse osmosis permeate which contains very little of the precious wine characters that would otherwise be lost.

Wine to be treated is separated by reverse osmosis into concentrate and permeate streams. The alcohol rich permeate is heated and passed through the special perstractive membrane contactor on the other side of which is a counter-flow of treated strip water.

How does the alcohol correction process work?
Alcohol passes through the membrane from the permeate into the water. The dealcoholised permeate is then cooled and recombined with the wine from which it was extracted, thus lowering the alcohol of the blend.

Typically, with one ‘pass’ the alcohol is reduced by 1 to 2% v/v. In practice, the wine being treated is circulated in one tank. Processing continues until the alcohol of the whole batch is reduced to the desired level.

Winemakers’ Questions concerning Memstar processes