Figure II: Oxygen in wine at different
stages of bottling process. [Friedel, 2007]
Physical laws, wine chemical compounds,
in addition to different solubilities,
densities, and diffusions between the
gases in the headspace and liquid phase
are essential parameters that will influence
the oxygen content of the bottled
wine. The key decision for the winemakerwill
bewhether to give thewine a
longer or shorter “potential lifespan.”
Oxygen uptake can also be influenced
depending on the filler-system
and design of the filling valves
or use of air evacuation in the bottle
before filling. This has been
proven and the effects can be
observed in the wine shortly after
Figures II and III showthe impact of
the oxygen content in wine determined
by the stage of bottling process
(Figure II) and the use of different filling
systems (Figure III).
One of the most
important parameters on the solubility
of oxygen in wine is temperature.When
using different filling procedures, different
temperatures of the wine in the bottling
process are given.
Generally, filling procedures describe
the way and methods that are used to
bring a sterile product into the bottle.
This can be done by filtration of thewine
or also by a pasteurization or warming
of the alcoholic beverage. Common filling
procedures are: cold aseptic with filtration
or flash pasteurization before bottling,
warm aseptic with or without
recooling, or cold with pasteurization
after bottling. Use of the three different
techniques will influence the solubility
of oxygen in the wine because of the different
temperature occurring but also the
enzymatical system which enables or
disables oxidation also.
Figure III: Oxygen in wine using different filling systems. [Mc Lellan, 1990]
EFFECT OF HEADSPACE VOLUME AND
TREATMENT ON OXYGEN CONTENT INWINE
By using different closures, the headspace
volume in the bottle can be influenced
significantly. The influence of
oxygen in the headspace can be measured
in the wine during the first storage
period after bottling.
The first storage period is the time
that is needed for the wine to consume
all the oxygen coming from the headspace.
This length of time is determined
by the content of oxygen in the
headspace, the pressure, temperature,
and wine components. From past
Geisenheim bottling experiments, our
experience is that this can last from 10
days up to three to four months.
Using an inert gas in the headspace
of the bottle between the fill-level of
the wine and the closure greatly
reduces the quantity of oxygen which
can be dissolved in a wine.
Figures IV and V demonstrate the
influence of CO2 and N2 headspace treatments
on the oxygen content in wine.
In Figure IV and V, the reducing
effect of a headspace treatment is
very evident. It is interesting to note
that by not flushing the headspace
with an inert gas, the oxygen content
in wine increases within days after
bottling. This results from oxygen in
the headspace being transferred continuously
into the liquid by diffusion
between the gaseous headspace and
Generally a good knowledge of the
composition of thewine (O2, CO2, SO2,
acetaldehyde, phenol-content) prior to
bottling is necessary to determine the
optimal preparation and bottling
process for a specific wine.
The input of oxygen into wine prior,
during, and after the bottling process is
determined by physical constraints
and chemical composition of a wine. It
can be influenced by using different
filling systems and procedures and,
more significantly, by using inert gases
to flush the headspace in the bottle and
evacuating bottles prior to filling.
For the past 15 years, the Department
of Enology and Wine Technology at the
Geisenheim Research Center, has conducted
various bottling trials in order to
evaluate alternative bottle closures.
Thanks to this research,we have been able
to observe the effects on oxygen transfer
into thewine described in this article.
For current projects dealing with the
measurement of oxygen transfer before
and during bottling,we use the non-invasive
and non-destructive “PreSens” fiber
optic oxygen measurement. Moreover,
we are examining, after bottling, development
of dissolved oxygen and sulphur
dioxide inwines during storage andmaturation.
The chemical and sensorial
changes inwine aromas are also analyzed
and correlated with different bottling
options and storage conditions.