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A Technical Guide for Wine Producers
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SAVING THE WINE BY MEANS OF ACID REMOVAL
Good news for winemakers is that thanks to new
technology, volatile acid may now be removed from wine that would
otherwise have to be wasted or distilled. Excessively high volatile acid imparts a vinegary
character to wine and for this reason, legal limits were instituted
world-wide regarding the permissible level of volatile acid in wine. In
South Africa this limit is 1,2 g per litre. Bacteriological activities
before, during or after fermentation may result in excessive volatile
acid. As far as could be ascertained, two undertakings are
currently capable of removing volatile acid and apparently they have saved
literally millions of litres of wine that may have been ruined by volatile
acid. They are VA Filtration and Envigoration, both of which
use mobile units to tie in with the seasonal requirements at cellars. VA Filtration is a partnership between a chemical
engineer, a filtration industry expert and winemaker Hardy Laubser. They
have been operational since August last year and already almost 1,5
million litres of wine have been processed, thus building a solid client
base. They use an advanced filtration process to remove
volatile acid from the wine and have just patented their process . which
has always been permissible, according to Hardy. "Our process is very
gentle and specifically removes only the volatile acid from the wine
without disturbing any of the other components." The other undertaking, Envigoration (a process
engineering company from Paarl), collaborated with Nicky Krone of Twee
Jonge Gezellen in Tulbagh, Dr Johan Marais of Nietvoorbij and counterparts
in America and Australia, where the technique is already being practised.
They have since patented their technique in South Africa. Envigoration has done much experimental work on various
cultivars. The process, namely reverse osmosis, has just been approved on
an experimental commercial basis by the Wine and Spirits Board. Although this technique is prohibited in the European
Union, it is considered acceptable cellar practice in Switzerland and the
New World wine countries. In South Africa it was not permissible for a
long time, but the Wine and Spirits Board reinvestigated the matter last
year. They requested Winetech, the wine industry's
co-ordinating research body, to make all available data about the effect
of the process available and indicate whether they believe this process
may be considered a normal cellar practice. Winetech's recommendation was
in favour of it. The removal of volatile acid from wine by means of
reverse osmosis may therefore be added to the list of "undesirable
flavours" in Table 7 of the regulations issued in terms of the Liquor
Products Act No 60 of 1989, which makes provision for substances that may
be removed from liquor products. "We give winemakers peace of mind," says Nicky Krone. In
the past wine with a high volatile acidity could be distilled, but the
distilled wine market no longer exists. "Our goal is definitely not to
support bad oenology, but to come to the rescue when isolated slip-ups
ruin valuable wines. Winemakers should remember that our process cannot
turn a bad wine into a good one, it rather restores valuable wines." "Politically we have always tried to remain in Europe's
good books, but meanwhile New World wine countries such as America and
Australia are applying this new technology. We should be careful not to be
such purists that we cause our own downfall. "We should remember furthermore that our climatological
conditions differ drastically from those of Europe. Their wine countries
are cold and they have low pH and high acid, with the result that bacteria
do not develop as quickly. In South Africa we can make the Dolly Parton
wines demanded by the rest of the world, soft, rounded, easily accessible
and fruity, but that requires a specific risk from the winemaker. Our
technology gives South African winemakers the opportunity to make optimal
use of our climate, but if something does go wrong, they have the
opportunity to rectify the matter." Both undertakings do not foresee treating millions of
litres of wine per annum, but reather seasonal activity when winemakers
experience more problems with volatile acid due to weather conditions
which cause the grapes to ripen too fast. VA Filtration
may be contacted on 083 269 5441 (Herman Smit) or 083 406 8652 (Hardy
Laubser).
Danie Nel of
Envigoration may be contacted on (021) 871 1877, or Nicky Krone on (023)
230 0680.
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