Open Bottle Decay, pt. 2

Let me first recap the first experiment (found here):  I compared three bottles of Ardbeg 10 

- one I slowly drank at a normal pace

- one opened and then placed under vacuum

- and one unopened bottle.  After I had drank through most of the first bottle, I did a blind tasting of the three samples and found that the one held under vacuum was best, while the one I drank slowly was my least favorite.  The conclusion was that keeping a bottle under vacuum is the way to go.  

Sooo.... I started keeping my Ardbeg under vacuum between pours.

But... wait a minute... before each drink I broke the vacuum.... which meant I broke the vacuum a lot... and this isn't what I tested.  The entire idea of keeping a bottle under vacuum is so that the oxygen in the air won’t interact with the whisky.  But does it negate the effect if you keep introducing air to the bottle every time you break the vacuum?  

So...  what I need to do is an experiment to check drinking a bottle held under vacuum in real world conditions where I will open and close a bottle rather often. 

And the result is... storing a bottle of whisky under vacuum between pours does not change the whisky.  Read on for all the details!

Procedure

Here’s the simple procedure we came up with:

1) Split a bottle of whisky into two separate, preferably identical bottles.  In this case I split the remaining Ardbeg 10 (about 1 bottles worth) into two bottles putting roughly 2/3 into one and 1/3 into the other. 

2) Replace the cork of one bottle with a vacuum stopper.  Evacuate the air in the bottle with the vaccum stopper.  

3) Drink through the corked bottle at my normal pace.  Every time the corked bottle is opened for a pour, break the vacuum on the other bottle, tilt it as if pouring, and then re-evacuate.  In other words, pretend you are taking a pour of of the bottle held under vacuum.  

Results

It took me about 7 months to drink the vacuumed bottle down to the same level as the corked bottle.  At the time of judgement, I had my wife pour a friend and I blind samples.  I didn't tell my friend what he was drinking, only that I was doing an experiment with an Islay whisky and wanted his honest comparison of the two.  

The results were exciting! 

The two samples were (virtually) identical.  

We had a hard time trying to find any differences between the two - such a hard time I had to ask my wife if she poured me two identical samples (she’s done that before to keep me really honest).  The Ardbeg stored under vacuum had a tad more sweetness on the nose and was ever so slightly smoother.  The negligible differences were only detectable because we were drinking the samples side-by-side and knew they were somehow “different”.  Let me try to give you an idea of how negligible… I would say the magnitude of the differences is about the same as the difference between two full bottles with a few drops of water added to one of the bottles.  

So when I said the results were exciting, I guess I really meant they were exciting in a geeky whiskynerd kind of way.

OK, so holding a peated whisky under vacuum while drinking through the bottle doesn’t help maintain flavor.  But what about a non-peated speyside?  I simultaneously conducted the experiment on a bottle of Glenmorangie the Tayne. 

Nope.  The two samples of Glenmorangie were the same too.

Conclusions

First, my overall conclusion with this experiment is what everyone else has already said:  If you store your whisky upright out of direct light and at a relatively constant room temperature, then there is no need for anything fancy.

But why?  Why doesn’t the whisky profile change?  Here's my hypothesis:  When the bottle held under vacuum is opened the surface of the liquid is oxidized nearly instantaneously after coming into contact with air.  If you are relatively gentle with your bottle the surface will remain constant and will mix very little with the volume when you pour it.  Similarly, the same will occur with an unevacuated bottle.  The surface will oxide but if the bottle is stored stationary and handled gently when poured, then the surface liquid will mix very little with the volume.  Therefore, holding a bottle under vacuum between pours has no affect on the characteristics of the whisky.

Finally,  it looks like I jumped the gun on ordering vacuum stoppers.  Anyone want one?  They've never been used and stored in a smoke-free house and are free to a good home.  (Update: The stoppers were lost when we moved!)