Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
email: Office@practicalwinery.com
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SEPTEMBER/OCTOBER 2009
WINEMAKING
IMPACT of oxygen level in wine at bottling
 
BY
R. Jung,
M. Freund,
C. Schüssler,
J. Seckler
Forschungsanstalt Geisenheim,
Fachgebiet Kellerwirtschaft
Geisenheim Research Center,
Section Enology and Wine Technlogy
e-mail: r.jung@fa-gm.de
O
xygen plays a crucial role in enology, and in the wine. Louis Pasteur noted that oxygen can make or break a wine. Oxygen management in wine thus represents a key component to maximize wine quality in relation to different markets and types of consumers.
Oxygen can dissolve in wine at several stages during winemaking, bottling and ageing. From a chemical perspective, its presence could result in wine oxidation, and thus change the quality and the extent of a wine’s life. Whereas extensive oxygen exposure might be the cause of serious defects, slight to moderate oxidation might benefit a wide range of wines, particularly reds. Carefully managing oxygen is a critical control factor during wine production.
The final step in winemaking – the bottling process – has a significant impact on the content of dissolved oxygen in wine.
Compared to other enological processes, the increase of oxygen before, during, and after bottling is relatively low. However, it is a very important stage because after sealing the bottle, a winemaker’s influence on the physically or chemically-dissolved oxygen in a wine is minimal. Therefore, the winemaker has to consider and define how he or she wants a wine to develop during storage before the actual moment of bottling.
IMPACT ON OXYGEN CONTENT IN WINE PRIOR TO BOTTLING
Oxygen transfer into a wine may vary, depending on wine composition. In Figure I, oxygen uptake changes depending on different enological treatments prior to bottling.
The first input of oxygen in the bottling process can occur when unloading wine from a tanker truck, and consequently during blending, fining, cooling, filtration, and immediately before bottling by pumping wine into the filler.
IMPACT ON OXYGEN CONTENT IN WINES WITH DIFFERENT FILLING SYSTEMS / PROCEDURES
Ideally, the bottling process should flow smoothly with a simple and economical system in order to microbiologically protect the wine and to conserve wine quality and its sensory characteristics.
In addition to temperature, bottling pressure is a concern that occurs when inserting a stopper into a bottle. If you do not use a
vacuum pump or insert CO2 into the headspace to reduce oxygen content, oxygen uptake will likely increase during bottling. Other elements influencing oxygen uptake during bottling are time and compounds in the wine itself (enzymes, katalytes [Cu or Fe] and redox system).
RELEVANCE TO COMMERCIAL WINEMAKER?
Generally the evolution of gases can be described by Boyle’s-Law “P x V = const.” During bottling, there are several gases (O2,N2,CO2) in the head space of the bottle and in the wine itself. Interactions between these gases and the liquid in the bottle can be influenced by using different filling systems or procedures.
Figure I: Impact of different enological treatments on oxygen uptake prior to bottling. [Deutsch, 1980]
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