MEMSTAR Reverse Osmosis | Exclusive to Vintech Pacific Ltd
Next generation Winemaking
MEMbrane - Separation - Treatment - And - Recombination
Memstar is a family of membrane-based processes for adjusting wine composition and enhancing quality.
Powerful winemaking tools to:
In general these applications "surgically" remove a low-molecular-weight constituent of the wine with minimal changes in the rest of the wine's composition.
All of these techniques are offered EXCLUSIVELY as on-site services in New Zealand by Vintech Pacific Ltd. These are proprietry processes for which Vintech Pacific is the sole New Zealand licensed operator.
We offer a preliminary laboratory test of most of the above procedures with our Microstar Mobile Laboratory:
>> Microstar Mobile Laboratory
MEMSTAR RO >> Reverse Osmosis
Memstar reverse osmosis equipment is the basis of all the other memstar processes. Wine is pumped at high pressure past a semi-permeable membrane. This membrane separates the wine into a flow of permeate which contains small molecules from the wine which have passed through differentially according to their size. The wine remains substantially on the high pressure, or retentate side of the membrane and becomes concentrated. The lower molecular weight fraction passes through to the low pressure, permeate side.
The separated permeate is then treated to remove a particular constituent and then recombined with the retentate. The result is a wine with substantially the same volume and constituents except that a specific component has been reduced, enhancing the perception of desirable flavours.
MEMSTAR AA >> Alcohol Adjustment
Memstar AA is a revolutionary new process for reducing excess wine alcohol. It is based on a combination of reverse osmosis and evaporative perstraction.
Wine to be treated is separated by reverse osmosis into retentate and permeate streams. The alcohol rich permeate is passed through a proprietary hydrophobic membrane array on the other side of which is a counter-flow of filtered strip water. Alcohol which is volatile, passes through the membrane from the permeate into the water. The rate at which it does this depends on the alcohol concentration gradient across the membrane and the temperature. The dealcoholised permeate is then recombined with the wine from which it was extracted, thus lowering the alcohol of the blend.
By treating RO permeate and not wine, the extraction of volatiles is reduced because of their limited passage from the wine into the permeate stream. This is controlled by the selection of appropriate membranes and operating parameters to maximise the passage of ethanol while limiting the passage of other compounds.
Typically, with one pass the alcohol is reduced by 0.9 to 1.5%. In practice the wine does not pass from tank to tank, the wine being treated is circulated in one tank. Processing continues until the alcohol of the whole batch is reduced to the desired level. The improvement in treated wines is clear and compelling.
It should be noted that it is theoretically impossible to completely dealcoholise the permeate because as the alcohol reduces, the rate of further alcohol movement across the membrane slows. In practice this means it is more efficient to remove a little alcohol from a lot of wine than to try to substantially dealcoholise a small batch.
The Memstar AA system includes vacuum pump, membrane contactors for degassing strip water and permeate, membrane contactors for alcohol stripping, water pumps and filtration, heat exchangers for pre-warming and heat recovery from strip water and permeate, a gas heater for heating water, all valves and pipework, gauges, instrumentation and PLC control.
Memstar AA is available as an on-site service on a short or long term service agreement or for sale including a license for the use of the technology.
MEMSTAR IX >> Volatile Acidity Removal
With the memstar IX process, the concentrations of acetic acid and ethyl acetate in the wine are greatly reduced while flavour elements and other wine constituents remain essentially unchanged.
The wine to be treated is circulated at high pressure through a reverse osmosis filtration plant to create a stream of permeate which contains the acetic acid and ethyl acetate to be removed. This permeate then passes to an anion exchange column where the acetic acid (as acetate) is absorbed on the selected resin prior to the permeate returning to the rest of the wine. The conditions in the column promote the hydrolysis of ethyl acetate to alcohol and acetic acid, this acetic acid also being adsorbed on the resin as above. This means that the wine with all its other acids, anions, sugars, tannins, flavour and colour does not come into contact with the absorptive resin. Flavours cannot be absorbed or contaminated and there is no ion exchange between the resin and the vinous components in the retentate. Nothing is added to the wine, and volume and alcohol content are not affected. The process continues for as long as necessary to remove the required amount of volatile acidity. Wine Network Technology offers this process as an on-site service for wineries.
MEMSTAR TR >> Brettanomyces and Smoke Taint Removal
With the memstar TR - taint removal technology, a permeate stream relatively rich in taint compounds is separated by the memstar RO. These taint compounds are then removed from the permeate by circulating it through a proprietary absorbent medium.
The process was developed in response to the massive problems with wines tainted by bush fire smoke in large areas of SE Australia and the Okanagan Valley of British Columbia in 2003. The indicator compounds guaiacol and 4- methylguaiacol were identified as being strongly correlated with this. A special membrane system was found that would reduce the levels of guaiacol and 4-methylguaiacol without also removing more desirable wine components. Since the introduction of memstar TR, millions of litres have been successfully recovered in Australia and Canada.
The process has proven similarly successful in reducing the levels of 4-ethylphenol and 4-ethylguaiacol in Brettanomyces tainted wine.