Introduction
Volumes have been written on the ideal conditions for storing unopened bottles of wine, but a more pragmatic question
for most wine-drinkers is that of how to store leftover wine from an unfinished bottle. The easiest method is to simply
recork the bottle; however, various more sophisticated methods exist including using a vacuum pump to reduce the
amount of air in the bottle, blanketing the wine with inert gas or decanting the leftover wine into a
smaller bottle (with little or no room for air).
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In this work, we undertake a controled experiment to gauge the performance of three popular wine-preservation methods: (1)
simply recorking the bottle, (2) using the VacuVin pump to remove most of the air in the bottle and (3) blanketing the
wine with the Private Preserve blend of gases (Nitrogen, Argon and Carbon Dioxide).
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Standard Corks |
VacuVin Pump |
Private Preserve |
It is well-known that the main reason that wine "goes bad" is over-exposure to oxygen, and therefore the above methods seek
to reduce the amount of oxygen that comes in contact with the wine. It is also well-known that wine (as with most any
food/beverage) will spoil more quickly at higher temperature, so storing the leftover wine in a refrigerator is advised.
The Experimental Setup
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We selected two contrasting wines for the tasting: The Casa Lapostolle, Sauvignon Blanc, 2005 (white), $10 and The J. Lohr,
"Seven Oaks" Cabernet Sauvignon, 2003 (red), $13. We purchased two bottles of each wine.
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For each of the two wines, the first bottle was carefully divided among three clean wine bottles (1/3 of a bottle, or
about 1 cup, in each). The second (unopened) bottle of each wine was kept as a control sample for the tasting.
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The bottles were then sealed using the three preservation methods: (1) simply recorking the bottle, (2) creating a partial
vacuum using the VacuVin pump and (3) using the Private Preserve spray can.
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Finally, the six sealed bottles were placed in the refrigerator (at about 34°F) for three days.
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The Tasting
Three days after sealing the bottles, we removed them from the refrigerator and let them come to the same temperature as the
control bottles (50°F for the white wines and 62°F for the red wines).
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We used four identical Riedel wine glasses (the Vinum series Bordeaux glasses), the bottoms of which were labeled with the
sample type ("C" = "cork only", "V" = "VacuVin", "G" = "Private Preserve Gas", "N" = "New (unopened) sample").
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We shuffled the four samples in such a way that neither of us knew which sample was which, and then tasted them (whites first,
and the reds an hour later).
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Results
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The single most striking result was that both samples (white & red) stored using the Private Preserve gas were markedly
worse than all the other samples. Indeed, the aroma/taste of these samples was not simply that of an oxidized (i.e. spoilt) wine,
but rather included some unpleasant, chemical and generally "off" aromas (burnt rubber? tar?). Perhaps this supposedly
"harmless" blend of gasses reacted adversly with the wine? It is also worth noting that these samples had many more
surface bubbles than the other samples (see the second glass from the bottom in the photograph).
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For the three remaining white wine samples, the results were as one might expect: the newly-opened sample had the freshest and
most focused character, with the VacuVin sample coming in a close second. The recorked sample survived remarkably well,
although was noticeably less fresh and flavorful than the newly-opened and VacuVin samples, at least in a side-by-side
comparison.
For the reds, we noticed differences among the three remaining samples, although they were difficult to classify as the wine
continuned to evolve in the glass. We originally identified the recorked bottle as having the "roundest" flavor and the
freshly-opened sample as being a little "harsh", with the VacuVin sample somewhere in between. Fifteen minutes later (alas,
only after we looked at the identifying labels on the bottoms of the glasses -- so we cannot claim that these tastings were
conducted blind), we found that the freshly-opened sample had "opened up" considerably, and was superior to the VacuVin and
recorked samples (which had now begun to fade and lose their appeal), as one might have expected.
Conclusions and Future Work
We found that simply recorking an unused bottle of wine and placing it in the refrigerator is quite effective, but the use of
the VacuVin pump was a noticeable improvement.
The poor performance of the Private Preserve gas is counterintuitive and certainly does not agree with the anecdotal
evidence of many wine-writers. We feel that this warrants further study, and in particular, we hope to conduct a similar
experiment comparing the Private Preserve gas with a pure-nitrogen system such as the Wine Keeper system
(again, using unopened bottles as a control).
Of course, there are many further tests that can be conducted to corroborate and/or complement this experiment. Perhaps the
most effective preservation methods depend of the age or style of the wine? How do various preservation systems work at
room-temperature? And the list goes on.
We hope to address these and other questions in future experiments of this kind.
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