FAQ’s
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Because it takes as long to reduce the VA from 1g/l to 0.5g/l as from 0.5g/l to 0.25g/l, there is no benefit in trying to over-treat a portion. In general it is preferable to remove a little VA from a lot of wine compared to taking a lot of VA from a little.
Yes, the high pH conditions in the anion exchange column hydrolyse the ethyl acetate ester into ethanol and acetic acid. The ethanol passes through the column and returns to the bulk of the wine and the acetic acid is adsorbed in the resin and so removed. This process takes place more slowly than the reduction of acetic acid because the ethyl acetate passes through the membrane more slowly.
Practically it has been found that it is possible to successfully treat some batches as small as 1,500 to 2,000 litres. Below this, problems of dilution arise because of mixing in the system. In any case, the real problem is the inefficiency of trying to treat such small batches. It takes as long to travel to the site; set up; clean the equipment and lines before and after then pack up for small and large jobs. Therefore a minimum fee applies and this can make the treatment of small batches unattractive.
The equipment will not tolerate any significant levels of grape or other solids in the wine. Otherwise it is reasonably tolerant of wines in a wide state of preparedness. To aid efficient processing we require that wines have turbidity no higher than 50NTU and are as warm as the winemaker is prepared to accept but certainly no less than 15 oC. Preferably (but not mandatory) they should be heat, cold and pectin stable and have been polish filtered. The better prepared the wine, the faster and more effective is the processing.
There are a number of utilities and other facilities required for the timely and efficient processing of wine when we are on-site. Full details are available from Memstar – please call +61 (0)3 9564 7089 or contact Memstar.
The cleaning of the RO generates a waste stream of a few hundred litres of water and trisodium phosphate plus several hundred more litres of rinse water. The ion exchange columns used for VA reduction are charged with sodium or potassium hydroxide. In the process, each recharge (once or twice a day) generates between 300 and a 1,000 litres of high pH sodium or potassium acetate solution plus another 2,000 litres of caustic solution rinsed from the column. The alcohol correction process generates a stream of alcoholic strip water. This is about 6% to 10% in alcoholic strength and is produced at 600 to 1500 litres per hour. This may be discarded if permitted or it may be sent away for distillation as it produces high quality spirit.
All Memstar equipment is available for sale; however some processes are subject to technology licensing arrangements so as a condition of the sale, a licence would need to be negotiated.
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