The following article appeared
in Wine Business Online
This outlines the continuing research into whether natural
(i.e. cork) closures are necessary for the proper maturation
and development of bottled wines.

Australian Closure Fund’s First Study "Proves
Oxygen Not Necessary for Ageing Bottled Wine
MEDIA RELEASE, On February
1, 2005 Allen Hart, Southcorp's Research & Development
Winemaker, released the findings of his study into "the
role of oxygen in the ageing of bottled wine" at an intimate presentation
for the Wine Press Club of NSW ( WPC ). Hart's research was completed
with the support of a $6,000 grant offered by the Australian
Closure Fund ( ACF ), supported by the WPC (and in conjunction
with Auscap, ACI and Grosset Wines). Jeffrey Grosset announced
the formation of the ACF in November 2003 when he presented the
inaugural Wine Press Club Lecture in Sydney .
Hart's paper was based upon a combination of wide ranging research,
Southcorp trials running since 1997 involving closures of varying
permeability and more recent trials conducted in collaboration
with the Australian Wine Research Institute on premium red wine
sealed with varying closures and filled to different ullages
of air space.
Hart concluded: "From this study it is apparent that
oxygen was not a vital component for the ongoing evolution
and maturation of these red wines after bottling. It is clear
that access to small but measurable amounts of oxygen (eg synthetic
closures), will accelerate the evolution and maturation of
red wine through oxidative reactions. However, red wine will
continue to evolve without measurable oxygen ingress via a
closure, primarily through what is assumed to be anaerobic
reactions. Some bottled wine may express "reductive" characters
in such an anaerobic environment, in contrast to the wine developing
oxidised characters in a more aerobic environment (but
the rankings indicated that these) are not considered commercially
unacceptable."
Commenting on Hart's presentation, Grosset said "Allen
Hart has, as a true researcher, stated that oxygen is not necessary ‘in
their experience'. But when this is added to the weight of
previous research we can now say with a high degree of confidence,
that oxygen is not necessary for ageing bottled wine, red or
white."
On the subject of 'reduced' characters, both Hart & Grosset
stated that they believed this is a winemaking, rather than a
wine closure issue.
Grosset went on to state "This result
has implications for wine closures. It tells us that the ideal
closure for ageing premium wine is one of low and consistent
or zero permeability. It also confirms that the most commonly
used closures (cork and synthetic) are either too permeable
and/or inconsistent. By contrast, closures are available that
reliably meet these conditions. This research does not tell
us whether minor improvements may be achieved by experimentation
within the zero to low permeability range. The ACF has determined
that it is possible to produce a closure of such precise permeability
in Australia . However, further research
in this area is required. In the meantime, setting aside marketing,
aesthetic and other issues such as taint, this work supports
the belief that, where quality is the number one priority,
reliable and effective zero to low permeability closures are
the obvious choice."
In closing the presentation, Grosset said: "So, what
does this research mean? It means that oxygen is not necessary
for ageing bottled wine… and it reinforces the decision
made by those premium producers who have chosen to use zero
or low permeability closures on all wines, confident that they
will age consistently. It confirms that choosing these types
of closures is appropriate for purely quality reasons, for
the sake of the wine, the wineries' reputation and the consumer."
Wine Press Club President Darren Jahn said that "The
Club's role was three-fold – to assist in the selection
of the suitable candidate; to facilitate distribution and publication
of the completed paper; and to provide a forum for discussion
of the results." He felt that the event "was
a tremendous success – both well-supported and well-debated – which
is true to our charter to provide a communications forum for
the wine industry." |