The availability of oxygen to a wine after bottling can have both beneficial and detrimental effects over time, and the effects can be altered by a wine’s history. A Chardonnay wine was treated four ways: aged in stainless steel with and without lees, and aged in oak barrels with and without lees. After 6 months aging, the wines were bottled and subjected to four levels of oxygen availability by varying the closure. The wines were monitored for dissolved and headspace oxygen, total consumed oxygen, SO2, aldehydes, esters and many standard endpoints. After bottling with substantial oxygen uptake, oxygen consumption was slow with 0.5 mg/L dissolved oxygen persisting in some bottles after 6 months. Sulfur dioxide decreased and 420 nm absorbance increased in response to higher accumulated oxygen exposure, expressed as Total Consumed Oxygen (TCO). A comparison of the oxygen versus sulfur dioxide consumed by the wine provided new insight into the development of oxidation products. Wines aged on yeast lees consumed more SO2 for each equivalent of oxygen consumed. As this wine also had lower levels of weak SO2 binding agents, we hypothesize that these substances interfere in protection by that preservative. At 12 months, using descriptive analysis, the 16 wines were rated for 13 attributes by 14 judges in triplicate. The aging container, stainless steel or oak barrels, resulted in the largest impact on descriptive analysis followed by the oxygen availability through the closure. Those with the highest TCO demonstrated noticeable oxidized characters. The ratio of SO2 versus O2 consumed may help identify wines that will become oxidized. SO2 binding agents and their role in affecting wine oxidation and SO2 analysis needs clarification.
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