W I N E     P R E S E R V A T I O N     T E S T
A C C E S S O R Y     S H O O T O U T

Have you ever had a half-bottle of wine you wanted to save for another time, and wondered what would be the best way to hold the wine for several days?

If you are not going to drink the left-over wine, there are a number of choices that will enable you to enjoy the wine on another day:...
  • Recork the bottle and keep it in a cool area
  • Pour the wine into a smaller container (such as a 375 ml bottle) to reduce the amount of air, AND keep it in a cool area
  • Use one of those pumps to vacuum the air out of the bottle, AND keep it in a cool area
  • Use one of the "Systems" that displaces the air with an inert gas, AND keep it in a cool area
You may have noted one similar factor "keep the bottle left-over wine in a cool area"... ...and then there is the question, "How many days will the wine keep?"

There are a number of factors that affect the answer, and the two most important ones are:
  • Exposure of the wine to oxygen
  • Temperature
I wanted to see what results could be typically expected by someone WITHOUT using a process that requires regular replenishment of expendables (notably the inert gas system).

  Before the test, a little about the science of wine deterioration...

Once a bottle of wine has been uncorked, the wine is exposed to air (which is about 21% oxygen). The oxygen in the air accelerates the oxidation of the wine. Wine is organic, and has a "life" that continues to evolve after being bottled. Some wineries inject a small amount of inert gas (CO2 or nitrogen) on top of the wine after bottling to disperse oxygen. The bottle then travels to a corking machine (corker) where a cork is compressed and pushed into the neck of the bottle. While this is happening the corker vacuums the air out of the bottle to form a negative pressure headspace. This removes any oxygen from the headspace...

The other significant factor was temperature, and wines will age faster at higher temperatures, so it helps to have a moderate ambient temperature when preserving an opened bottle of wine.

..and now, back to the test...

I used two identical bottles of Pinot Noir, and divided the wine into the following four containers:
One of the original bottles half-full with a cork (Control Bottle). The other original bottle half-full with a vacuum sealer. A set of 375 ML & 180 ML "cruets" with corks. A recycled 375 ML wine bottle.

Epicurean Wine
Preservation System

Wine For Later

375 ML bottle

B E G I N N I N G       S T A T E
Half full (320 ML) & closed with a cork. Half full (320 ML) & sealed with a vacuum stopper, with air pumped-out. Larger cruet full (360 ML) & closed with a cork (No air). Full (400 ML) & closed with a cork (No Air).
A D D I T I O N A L       N O T E S
  • Approximately 45 ML was poured from each bottle into glasses for a control taste against which all subsequent tastes would be compared, and to ensure both bottles were consistent.
  • The cruet and 375 ML bottle were both filled so that there would be no air between the top of the cork and the wine surface.
  • Once the 375 ML cruet had been sampled (on Day 2), 200 ML was immediately poured into the smaller cruet and closed with no air gap -- this cruet was sampled only after the larger cruet was completely empty.
  • In between tastes, the samples were all held in a cool room where the temperature was maintained between 66 & 72 degrees**
  • Wines were sampled every other day until the first signs of oxidation (which turned out to be six days), then daily until completely consumed, or undrinkable. (i.e.: Samples tasted on Days 0, 2, 4, 6, 7, 8, 9 & 10)

  • **We experienced a cold spell during the test, and the control room dropped from 72 on Day Zero to the mid-60's, and was about 5 degrees lower than planned (see Min/Max recording thermometer to right) -- this may have extended the life of the wine longer than anticipated...
    T A S T I N G       N O T E S
    The control taste, just after the bottles were opened, showed the 2003 Domaine Carneros Pinot Noir to be a fairly nice wine, and drinking well. (FYI, This was marked as "Day Zero")...

      The color was bright, dark-cherry red, with very good and brilliant clarity. There were traces of vanilla and cinnamon on the nose, with some soft cherry, blackberry and earthy overtones; overall, a nice medium intensity. The wine was a little tight on the palate, with moderately stringent tannins. It tasted a bit young, showing a little tartness, with a medium body and fruit. The flavor was good, with a tight finish that had a hint of smoke and lingering tannins. Overall, it was a well-balanced, soft wine, if a bit young; and rated at 88 points.  

    The chart below shows how each of the various storage methods affected the wine: All dropped-off after 5 days, withthe control bottle taking a plunge into undrinkability, and the vacuum system holding above 80 points for the longest WITH ONE NOTABLE EXCEPTION:

    The smaller cruet was filled and set aside on Day 2, just after the larger cruet was first opened. This smaller cruet was not exposed to any more air until Day 8, and when it was tasted on Day 8, it scored the same high 88 points as the "Day Zero" control taste. (It should also be noted that the score for the control bottle rose to 89 points on Day 2, perhaps showing a benefit to being exposed to a bit of air for a day...

    There was a reassuring "pop" each time the vacuum sealed bottle was opened for a taste, reinforcing the fact that the contents were in a partial vacuum...       ...however, this could be a double-edged sword because the lower pressure in the evacuated bottle encourages dissolved gasses in the wine to "titrate" from the wine into the air where they evaporate and are lost. This can be observed in some cases as a stream of tiny bubbles coming out of the wine when the bottle is being pumped. This may be the proverbial "smoking gun", that resulted in the loss of flavor from the vacuumed bottle. (I suspect that these gasses include some of the aroma, and taste factors that are sensed when the wine is sipped.)
    C O N C L U S I O N S
    My first conclusion is that an opened bottle of wine is unlikely to remain drinkable for a week, so some sort of preservation method is needed, if you want the wine to hold that long. Having said that, some options are better than others. The two primary factors you can control are:
  • Keep the wine in a cool location
  • Limit the amount of air the wine is exposed to

  • To stretch to a full week, the most effective method was a small bottle that could be filled to the top so there is no air between the cork and the wine.

    The next most effective method is one of the vacuum pumps that reduces the air pressure in the bottle (remember, the remaining air will still be 20% oxygen), the pump just reduces the volume of air.

    I suspect that the Nitrogen displacement canisters may be more effective, but you would have to purchase refills periodically, and at the beginning of this test, we said that we would not use any method that required expendable supplies...

    For you techies, here is the chart:

    ** 'Cruet Bottle Change': As noted above, once the first taste was poured from the 375 ml cruet, the 200 ml cruet was filled from the 375 ml cruet, and subsequent sampling continued from the partially full 375 ml cruet. Once the 375 ml cruet was completely empty, sampling continued from the 200 ml cruet; hence 'Cruet Bottle Change' (and an expected improvement because the wine had been shielded longer from oxidation).
    P O S T       S C R I P T
    OKAY... so you say it is unrealistic to OPEN and try these bottles daily, because that exposes the wine to more air, and if you had saved a half-bottle, you would most likely consume it whenever you opened it next...

    I completely agree!...       So check out my next test of a Cabernet Sauvignon, which I held for a full week before opening the test bottles...
    C A B E R N E T       T E S T
    This is a similar set-up as before, but I eliminated the 375 ML bottle because since the bottles will not be opened daily, it should have the same result as the 375 ML cruet after one week.

    Also, as fate would have it, the temperature was a bit warmer, so the control room was maintained between 72 and 75 degrees -- a full 5 degrees warmer than the Pinot Noir test...

    C A B E R N E T       T A S T I N G       N O T E S
    The small cruet was filled (200 ML), and and closed with a cork, allowing no air at all in the cruet. 90 ML was set aside for the initial taste, and the remaining 460 ML was evenly divided between two clean 400 ML bottles, which allowed about 140 ML of air into each bottle. One was sealed with a vacuum pump, and the other closed with a cork.

    The control taste showed the Franciscan Oakville Estate 2000 Cabernet Sauvignon to be an excellent Cabernet, and drinking quite well. (FYI, This was marked as "Day Zero")...

      The color was dark-burgundy, with very good and brilliant clarity. The boquet was nicely oaked with a hint of vanilla and earth. It was a medium rich intensity on the palate; velvety soft for a Cabernet, and a little young. The flavor was rich with good body and fruit, but with a tight finish, perhaps from being a bit too young, a hint of alcohol, and lingering tannins. Overall, a very good balance; a nice mellow softness, and would likely improve for several more years; rated at 90 points.  

    The chart below actually only consisted of two data points for each sample: the Day Zero control score, and the score for each of the samples when they were tasted on Day 8 -- it was clear that there was no value in extending the tasting for any more days because by Day 8, two of the samples had gone over the edge.

    I curved the lines to reflect that the deterioration is not linear, but since this test did not take samples at any intermediate point, it is not clear where the precise point is when the wines became undrinkable (the previous test can be used for this purpose).

    C O N C L U S I O N S
    I believe it is clear that air should be considered the enemy of opened wine!     ...and while removing some of the air helps, it is not as good as preventing the air from contacting the wine at all.

    You can see that after 8 days, the vacuum method in both tests, took the wine from around 90 points to just above 70 points, while the cruet method preserved the wine very close to the original score.

    My main conclusion is that these red wines (kept at room temperature) would best be consumed within 5 days of being opened; longer if they can be sealed in a bottle with no air.

    Here is the chart from the second test:

    P O S T       P O S T       S C R I P T
    FYI, The cruet product I used, used to be sold as "Wine For Later", and consists of two clear glass beaker-shaped cruets with glass stoppers, I used corks instead to keep more air out (photos above & below)... The actual volumes are 360 ML and 200 ML, respectively. Any small bottle can be used, and I have saved a few 375 ML bottles for this purpose (and found their actual "no-air volume" to be about 400 ML).

    The vacuum system was the "Epicurean Wine Saver Preservation System", which is an electric hand-held pump that uses special corks to maintain the partial vacuum. It worked well and was easy to use. There are other brands and models, including manual hand-pumps. This method is certainly going to help any time you don't have enough wine to fill a small bottle to the top.

    The bottom line is that a small bottle that can be sealed with a cork is best, and on the occasions when there isn't enough wine to completely fill the bottle, a vacuum pump will improve the results for bottles that have a volume of air below the cork.

    Click on these images to enlarge in a new window:
    Before opening the wines
    Set-up on Day Zero
    Day Zero
    First Pour -- Day Zero
    Day 6
    Day Six

    Click the image below for Daily Tasting Details (PDF):
    Daily Tasting Details

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