How Best to Store Your Whisky
The question of how best to store your whisky comes up a lot in the whisky world. While the casual drinker may only have a bottle or two of different whiskies around at any given time, enthusiasts tend to collect quite a variety. Given the costs associated with some of these bottles, what is the best way to store them to ensure minimal change in the flavour over time? There are a lot opinions available online – some of which actually run counter to evidence. So let me walk you through the best evidence-supported recommendations.
This article has been updated twice, with new links provided for additional studies, as described below. Latest update was March 31, 2020.
1. Sealed bottles (i.e., new and unopened)
For sealed bottles, the answer is fairly easy – store your whisky upright, in a dark (and preferably cool) place, minimizing light and temperature fluctuations. I’ll explain each of the reasons below.
1.1. Keep Them Upright
Upright is most important, as the high proof ethanol in whisky will degrade the cork over time if stored on the side – dissolving the cork, and tainting the flavour of the whisky. This comes as a surprise to most wine drinkers, who are always advised to keep wine bottles on their side. But that is because wine is much lower proof (lower alcohol content relative to water), and so the water in wine keeps the cork from drying out. This is important, as a dried-out cork will let air in, spoiling the wine. Unopened whisky bottles are fully sealed, and the contents do not change in the bottle so long as they stay sealed and well stored.
I’ve seen comments online about “moistening” the cork periodically in whisky bottles (by temporarily tilting the bottle on the side). This does nothing of the sort, as the higher ethanol content is actually drying out the cork. But periodic contact of the whisky with the cork is not likely to harm it much – after all, this happens all the time when a bottle is handled or shipped.
On that point, I routinely pick up bottles in my travels, and pack them in my checked suitcase for return travel. I have never had an issue with cork leakage in new, sealed bottles. Where you will get into trouble is with open bottles that are only partially-filled (as the extra air contracts and expands with pressure changes at altitude, causing the cork to pop out – more on this later). Note that minor leakage can occur with some screw caps enclosures, even if the seal is unbroken. Air pressure changes can cause small leaks as there is “wiggle room” for the cap to loosen slightly. You will want to give screw-caps an extra hand-tighten to make sure they aren’t loose to start, and encase the bottles in sealed containers. I use extra-large Ziploc freezer bags, and they do well to capture any minor leakage. One exception to placing whisky in checked luggage is for smaller planes (used for short hops), where the cargo hold may not be within the pressurized cabin area. For any jetliner, you won’t have this concern, as the cargo holds are all pressurized.
Your bigger risk traveling with checked bottles is breaking at the neck point, due to rough handling of your bag. So always make sure they are well-wrapped in clothes or bubble wrap (I find laser toner cartridge shipping bags great for this, with a pair of socks wrapped around the bottle neck). Also try to pack in the middle of the suitcase, not near an edge.
1.2. Avoid Natural Light
Many studies have shown that sunlight is one of the biggest threats to whisky (some links provided below in my discussion of open bottles). Even indirect natural light will induce changes over time, so you are best storing your whisky in the dark – like in a cupboard with doors kept closed. Keeping them in their cardboard boxes/tubes will also help in protecting against light pollution. But I’ve also seen suggestions to ditch the cardboard boxes if you are planning for very long-term storage (i.e., decades), as the cardboard/glue can become a substrate for microbial/fungal contamination. But that only matters for the serious collector (who likely has a proper climate controlled dark environment for their whisky anyway).
UPDATE 03/31/20: The final 24-month analysis by Breaking Bourbon on open bottles found that direct sunlight did indeed significantly effect the taste of bourbon. Note that this effect was additive with air exposure (i.e., bottles with more headspace showed greater degradation). Scroll down for further studies looking at air exposure in open bottles.
1.3. Avoid High Heat and/or Temperature Fluctuations
Cool storage is better than warm, but fluctuations in temperature are potentially even more of a concern (again, see some of the links below for studies on open bottles). A fascinating story is the discovery of century-old crates of Scotch whisky in the Antarctic permafrost – as recounted here. The whisky was apparently still in excellent shape. Actual storage temperature probably doesn’t matter much, as long as it is not higher than room temperature – and so long as it reasonably stable (i.e., not in your attic, or next to your furnace!)
2. Open Bottles
Once opened, whisky can start to show age and exposure effects in the bottle. This is a different sort of “aging” than what happens in the barrel during whisky production, which is necessary to make whisky (see my Sources of Whisky Flavour page for more info). How noticeable these changes may be is an interesting question – and one that I will return to in section 3 after I describe the results from a number of interesting studies below.
The common concern here is due to the increasing presence of air in an open whisky bottle.
As an aside, it is a pet peeve of mine that most people refer to this incorrectly as “oxidation.” Oxidation refers to a specific chemical reaction that involves a transfer of electrons between chemical species (specifically, the stripping of electrons from the chemical that gets “oxidized”). Given the high proof of whisky, classic oxidative reactions at the air-liquid interface in bottles are unlikely to be contributing in a major way to changing characteristics over time (a fact borne out by empirical testing).
Furthermore, there are actually two separate issues potentially at play here – the repeated air exchange each time you pour a dram from a bottle, and the expanding volume of air in the bottle over time.
You might not have thought of the first one, but it seems a lot more likely that it is not the new air going into the bottle that is having any effect, but rather the repeated escape of the headspace air moving out of the bottle (i.e., the air exchange). The reason for this has to do with vapour pressure in a bottle – ethanol is more volatile than water, and so (in gas form) takes up more of the headspace. Every time you pour a dram and exchange the headspace you are effectively diluting your whisky minutely, by effectively increasing the relative amount of water to ethanol inside the bottle. The same could also be true of the aromatic compounds that give whisky its smell and taste. Basically, every time you exchange the air, the headspace refills with higher volatile components from the liquid – which then get depleted on the next pour, starting the whole process all over again. And over time, the volume of that air headspace in the bottle keeps growing, accelerating the pull-out of volatile molecules each time it is replaced. At least in theory, this could lead to a reduction in flavour over time.
But is this really a concern in practice? Unfortunately, the academic literature (which I have reviewed) is not too concerned on this point. The few studies done typically explore these questions from a theoretical perspective, under acute laboratory conditions with specialized preparations that don’t reflect long-term use or storage concerns of open bottles. But there are a number of whisky enthusiast/citizen scientist experiments that are worth considering here (including some with analytical testing). At the end of the day, it is empirical observations using sensory analysis (i.e., tasting with blind tasters) that is the best way to compare the effects of potential storage conditions on perceived flavour.
As previously mentioned on this page, at least one whisky enthusiast study has suggested open bottles with greater air headspace show more advanced degradation when exposed to sunlight. But what about properly stored open bottles? Cited below are a small study by Mattias Klasson of scotchwhisky.com, and a more rigorous and detailed study by Marcus Fan. Both of these studies found noticeable effects from large air volumes over time, depending on the storage conditions.
UPDATE 12/23/19: The Fan website appears to be down, but you can use this link to see the last saved way-back-machine cache of the site. Alternatively, you can download a copy of the Fan study here, in plain-text format. You may also find the Scotch Test Dummies test mentioned in the comments below interesting as well. While that last example wasn’t done blind, the examiners were clearly surprised by the result (i.e., expected the opposite finding).
UPDATE 03/31/20: Two additional studies are described below, both involving blind triangle taste tasting and analytical testing, by Wade Woodward and the British Bourbon Society.
Before I get into each of their specific testing results, a brief explanation of popular storage options for open bottles of whisky is presented below (many of these are tested in the individual studies linked to above).
2.1. Leave Them Alone
The first option is to simply leave the whisky in the well-capped bottle until it is gone. But a popular belief online is that the air-induced changes in whisky intensify once the bottle has dropped to less than half volume – and becomes extreme once only a small volume is left (i.e., only a “heel” of whisky left in the bottle). This would be consistent with the headspace air-exchange line of reasoning provided above. So practically, you probably don’t even need to worry until you pass the point where there is more air in the bottle than whisky.
A related question comes up about storing whisky in crystal glass decanters (for display purposes). Here again, the indirect light issue comes into play, as you will degrade the whisky over time (even faster than you will from the air). Even worse, those clear crystal decanters are actually lead crystal. The high proof alcohol in whisky will gradually extract lead from the glass, dosing you with something you will definitely want to avoid.
So what can you do to minimize air effects once the whisky volume drops substantially? Here are the most popular options:
2.2. Use Smaller Glass Bottles
This is probably the most popular option in the whisky enthusiast community. To minimize air headspace, simply pour the whisky into smaller glass bottles. Commonly available are Boston round bottles in 0.5, 1, 2, 4, 8, and 16 oz sizes. These are available in clear glass or, better yet to minimize light effects, amber or cobalt blue glass. The results of the Breaking Bourbon, Fan and Klasson studies support this method as one of the best ways to minimize air effects.
Bottles caps matter here though. The best bottle enclosures are phenolic screw caps (made from black polypropylene). But do not use the cheaper ones with paper liners. Instead, use only polycone liners (see attached photo comparison).
The cheaper caps use pulp paper with a thin polyethylene coating, and are intended for aqueous solutions only (i.e., pure water-based). These will degrade rapidly in direct contact with high-proof alcohol fumes. You will soon find the liner contents dissolving into your whisky, making a disgusting mess. I’ve seen this happen to a few sample bottles I’ve received in swaps with other reviewers, when I didn’t check the caps (for samples I didn’t get to right away). Polycone liners are conical-shaped liners made of an oil-resistant plastic – and are designed to resist chemicals, solvents, oils, etc.
This decanting approach into smaller glass bottles is the consistent first choice across all studies for long-term storage. My personal experience also supports this conclusion.
As an aside, a cheaper alternative is to use clear plastic PET (polyethylene terephthalate) bottles. While it is true that some bottom-shelf whiskies come in PET containers (along with many other food and liquid stuffs), the long-term effect of storage of high-proof alcohol in these containers is unknown. It is reasonable to worry about the potential extraction of plasticizers over time (i.e., the additives used during production to keep the plastic from becoming too brittle).
At a minimum, it would be important to ensure you are getting food-grade PET bottles, with proper polycone caps. In the Klasson study, they use “cheap PET bottles” (source not identified), and found a significant change in flavour over time. I’ve kept whisky in food-grade PET bottles for up to 6 months, and have not noticed any off flavours. But I would consider this a riskier proposition, and recommend you stick with glass bottles if at all possible.
2.3. Fill Up the Original Bottle with Glass Marbles
A seemingly ingenious solution to the air volume issue is to pour glass marbles into the original bottle as the whisky volume drops, thus minimizing air headspace. Sounds reasonable, right? Except this approach means that you are greatly increasing the whisky-to-glass ratio over time, especially as the volume drops. All that increased glass surface area is an opportunity for interactions to occur (i.e., there is more surface for the congeners and other flavour molecules in the whisky to “stick” to).
At a minimum, you would need to ensure the marbles were scrupulously cleaned and sterilized before use. And I have no idea where you would get food-grade glass marbles to start with – children’s toy marbles are not likely to be made of high quality glass, and are likely to contain various contaminants that could leach out in the presence of high proof alcohol (e.g., lead). Conducted properly though, this approach is likely to work – as demonstrated in the Fan study. But I think you are best to decant into smaller glass bottles.
2.4. Neutral Gas Spray (e.g. Wine Preserve)
This is a popular option for those coming from the wine world. Indeed, I frequently see this recommended in online whisky forums – but one that I must caution against using.
The principle is that an inert, neutral gas like argon (Ar) can be sprayed over the surface of the liquid, thus preventing the lighter-weight oxygen (O2) from reaching the wine (or whisky) once re-corked. There are various “wine preserve” brands out there, each with their particular (and often undisclosed) blend of argon, nitrogen (N2) and carbon dioxide (CO2).
Keep in mind, these sprays were all developed and tested on wine – it is unknown how the much higher proof whisky would react. One obvious concern is that the lower-proof wine “preserved” this way was only meant to be kept for up to a week or two. Long-term storage effects (typically months to years) for high-proof whisky are thus largely unknown.
A potential problem here is that the spray canisters need a food-grade aerosol propellant in order to eject the “inert” gas down the long extended tube into the whisky. In the old days, this was Freon – but that has since been replaced by butane and propane. It is not at all clear what the long-term effects of adding butane/propane, as well as Ar/N2/CO2, inside a whisky bottle would be. The chemistry that occurs at the air interface of high-proof whisky is complex and not fully understood – adding these extra variables would be a concern.
Indeed, in the study by by Fan, the most popular neutral gas spray – Private Preserve Wine Preserver (shown above) – consistently induced greater flavour change than any other condition beyond indirect sunlight (!). While exposure to regular air had noticeable effects when the whisky volume was very low (e.g. 150 mL in a 750 mL bottle), these were almost twice as noticeable when wine preserve spray was used. Simply put, wine preserve was considerably worse than just regular air exposure in a bottle. See also these (unblinded) results from the Scotch Test Dummies.
On the basis of these findings, I strongly recommend you do NOT use neutral gas sprays in your whisky bottles.
2.5 Vacuum Seals
Another popular option from the wine world. Typically, a specialized rubber cork is placed at the opening of the wine bottle, and a hand pump is used to extract most of the air from the bottle (creating a partial vacuum). I’ve used this myself, and it does help keep wine flavourful for a few days (compared to simply re-corking).
For whisky, there are two main concerns. For one, the seal will not last over the longer term, and the high-proof ethanol is likely to degrade the rubber gaskets over time. I’ve not seen a whisky study done using wine bottle vacuum seals, but the Fan study did look at placing the small sealed whisky bottles in standard food vacuum sealer bags. Their results showed no net benefit to this whisky using this method (and I wouldn’t have expected any).
But the more important point is that a proper vacuum seal on a bottle would be expected to increase the pull of ethanol and other high-volatile aromatics out of the whisky over time, as explained here. If effective dilution of the whisky is the end result of repeated air exchange, vacuum seals would be expected to make this worse.
Either way, I recommend you stick to storage without the vacuum seal complexity.
2.6 Parafilm
A standard in any chemistry or biology lab, Parafilm is a thin plastic film of paraffin wax. Paraffin is a soft, colourless wax used for making candles and crayons, among other things. Parafilm is used in labs to temporarily seal an open container (like an Erlenmeyer flask), or for longer-term storage of lidded containers (where are you are trying to prevent moisture or air contamination).
While Parafilm can certainly be degraded by various chemical solvents, it is relatively resistant to ethanol. Unfortunately, Parafilm is still relatively gas permeable, so it is best suited to serve as physical barrier for liquid penetration, not gas phase exchange.
I personally use it when transporting whisky – especially when carrying sample bottles on airplanes. The pressure changes are likely to cause leaks, and Parafilm is very helpful in minimizing these. But as a way to preserve whisky in the bottle, it likely only of minimal effectiveness – and therefore probably not worth the effort.
3. Do Detectable Changes in Whisky Really Occur, and if so, Over What Time Frame?
Much of the preceding section was predicated on the common belief that whisky changes over time, and that these changes are noticeable to a whisky drinker. Indeed, the testing experiments described above by Breaking Bourbon, Marcus Fan and Mattias Klasson all demonstrate changes over time that were detectable by experienced tasters blind to sample conditions. Of course, the magnitude of those effects were highly dependent on the specific controlled storage conditions examined. So the real practical question is, how much of a change are we really talking about inside a typical open bottle left corked on a shelf?
In this regard, two more recent studies are helpful. Both Wade Woodward and the British Bourbon Society did proper blind triangle taste tasting for existing bottles. This is actually the same method used by whisky makers for minimizing batch variation across establishing bottlings, as I describe on my Single Malts vs. Blends – Understanding Whisky page (please see “How Consistency is Maintained Across Batches in Scotch” for more background).
For these two studies, two identical bottles from a common batch were used for comparisons – one that had stayed sealed, and one that was opened, experienced repeated samplings, and then left for a period of time corked with reduced volume (i.e., significant air headspace). A blind panel of experienced tasters was presented with three identical-looking samples in a triangle test format – two samples from one bottle and one from the other. They do not know which is which, and are asked only if they can identify the “odd one out” from the array (i.e., which sample is different from the other two).
In the British Bourbon Society study, with one bottle that had been open for half a year, only two of the six blind tasters correctly identified the odd one out. That is exactly the result you would expect from random chance alone, when asked to identify one out of three samples. And incidentally, those two correct reviewers both found the opened bottle to have more flavour, not less. In the Woodward study, not one of the ten blind tasters correctly identified the odd one out for a bottle that had been open for one year. And yet they all believed they could tell a difference – they were all wrong, even though they were actually given the option of reporting no observed difference in that study.
Both the BBS and Woodward studies followed up with analytical testing of aroma molecules in their bottles; Headspace Solid Phase Microextraction (SPME) followed by Gas Chromatography in the BBS study, and Gas Chromatography – Mass Spectrometry (GC/MS) in the Woodward study. Both of these tests can measure molecules down to level of parts per million. Both found virtually identical patterns for all molecules detectable in both the old and new bottles (and dozens of individual molecules were detected and measured for each bottle). There was no measurable difference in the levels of any of the major species they could identify.
Taken together, these studies call into the question whether air-induced changes inside a whisky bottle matter over the six month to one-year time frame.
4. Interim Conclusions
Based on the evidence to date, you will want to keep your whisky upright and in the dark (preferably in a consistently cool place). But you probably do not need to stress too much about any potential air exchange effects over the short term (i.e., under a year), or for bottles that are still more liquid than air.
If you want to ensure the flavour profile remains as consistent as possible for open bottles over a longer term, your best bet would be to decant into small glass bottles with proper polycone caps, taking care to minimize any air headspace. Just about anything else brings with it potential risks, and either lacks evidence of effectiveness (e.g., vacuum seals), or has clear evidence of negative effects (e.g., neutral gas sprays).
I hope you found the above useful. I’ll update this post if any new studies come out that I think are of particular relevance.
What are your thoughts on fluorescent light on whiskey? I’ve tried to determine if fluorescent light penetrates glass but to no clear outcome.
Fluorescent light certainly penetrates glass. But fluorescent lights emit a reduced spectrum compared to natural sunlight, but it’s hard to know how that would compare in terms of its effects on whisky. I’ve not seen anyone compare different artificial light sources compared to natural light. My guess is that it would be less harmful – but how much less is hard to know.
Fluorescent lights emit ultraviolet light that’s converted to visible light when it excites the phosphors. Some of the UV gets out, and that’s what’s damaging to whisky. So no, don’t use them.
Also, LED white lights are actually fluorescent lights – they emit UV from the die that excites phosphors. So don’t use them either.
Good old incandescent bulbs are still the best for this.
It’s true that fluorescent lights do emit some UV, but at relatively low levels (certainly much less than natural light).
White LEDs are not fluorescent, but they are based on blue LEDs (with additional phosphors to warm up the tint), so they may also emit some UV – but at incredibly low levels.
I agree that incandescent lights would likely emit the lowest level of UV of all three artificial sources (but still some, at vanishingly low levels). Outside of red or green LEDs, of course, which have a very restrictive emission spectrum.
This is a very useful post, as is your site, thank you very much.
Talking about whisky storage with gas, have you heard of the Scotch Test Dummies little experiment?
https://youtu.be/8BHAn4SKdBY
No, I hadn’t seen that video before – but their results do not surprise me at all, based on the findings reported here (i.e., the nose was clearly impaired in both cases at one year with Private Preserve spray, as was the palate on the peated version).
A limitation is that they weren’t doing the testing blind to which condition the bottles had been stored under. But they were clearly surprised by the results, as they stated they had expected no change. Going forward, they are now biased as to the outcome – but it should be still be interesting to see what their subjective impressions are. Thanks for the sharing!
Electrician here, fluorescent lights output UV light (i’ve seen it bleach shades for them and wire insulation) so i would advise against using it. LED or incandescent lighting would be better.
Speaking strictly theoretically, a potential concern with vacuum seals is that you are not truly creating a gas-free space; rather, the more volatile compounds could be expected to vaporize in relatively greater amount, thus affecting the remaining liquid. Just a guess.
(Disclaimer, I have been guilty of the “cork moistening” method but quit when the fit of the cork become more not less “loose,” and there was visible particluate in the bottle. More by default than by design, I just leave ’em alone in a dark basement cupboard.)
An clearly-written and thoughtful article. Very useful. Thank you.
Interesting thought on the propellant in private reserve–I have noticed varied results using it and maybe that explains it. I’ve been looking into using a bulk cylinder of argon or nitrogen to save cash and waste of using so many bottles of private reserve. Since there is no propellant, just a regulator… what would you think about that? Also, specifically for whisky, which would you go with, nitrogen or argon? The cost difference doesn’t seem to be too much of an issue considering the amounts I’d be using.
Thanks, and great article by the way.
I think losing the propellant, at a minimum, is a good idea to start. But I wouls still worry about the effect of any inert gas in a whisky bottle without long-term comparative testing first. We need more long-term studies.
Liquor Hound on YouTube has been useing pure Argon from a welding supply so no propellant . Last I heard he has a collection of over 2800 bottles and he swears by it. It would be awesome if we could have him do an updated video on this subject
It was interesting when you explained that we should avoid filling the bottle with marbles because it increases the liquor to glass ratio. My husband mentioned that he wants to find a local alcohol delivery service so he doesn’t have to drive to the liquor store when he gets off of work. I know he likes whiskey, so your tips about how to store it will be really helpful going forward!
Excellent article (and reader comments), thank you.
My comments are only about long-term storage (1+ years) for whisky geeks/malt mates/pat pals that like to keep their open whiskies in the original bottles. I and family collect whisky (mainly malts, for drinking!) and have many open bottles which are enjoyed over several years. After opening a new bottle, and consuming past the shoulder, the closed bottle (with air in head-space) is allowed to breathe for 1 month (2-3 if sulphured). Afterwards (incl. after every use), the head-space is completely filled with food-grade argon dispensed from a pressurized cylinder tank (no propellant). The bottles are then stored upright, in dark, without paraffin film, at room temp. We have been able to successfully preserve whiskies for several years with no discernible change, in our subjective experience. We’ve been enjoying whisky for 30+ years.
I question whether the aerosol spray “blanket layer” approach works long-term. Gases naturally mix with one another at room temperature due to the physics of diffusion. It’s my understanding that gases will not remain layered in the bottle by weight. Given little time, the various gas molecules (inert and air) simply move about and mix.
It’s my understanding that the wine industry commonly tests head-spaces in fermenting vats/tanks. Inert argon gas, nitrogen, or carbon dioxide is often used to separate wine from air (oxygen) during wine production. Laser-based gas analysis equipment is used to determine chemical composition in head-spaces. All the head-space above the wine is filled with protective gas to displace the air (not merely a layer, even with heavier-than-air argon).
I have read that such analysis equipment has been used to test the head-space of a part-emptied bottle of whisky (laser projected into the bottle, similar to industry testing of contents within sealed bottles of wine), where the remaining whisky was preserved with a carefully-introduced aerosol spray “blanket layer”. The results were that over hours the injected gases and air naturally mixed in the head-space (diffusion). There used to be a web article explaining this whisky testing by technicians with a company (Scandinavian, if I recall correctly) supplying such analysis equipment to the wine industry. I searched to provide a link, but don’t see the article anymore.
Eric, I fully agree with your call for long-term comparative testing. The info I’ve shared here is merely based on subjective experience, not blind triangle tasting. One can’t draw any conclusion without proper experimental tasting. I merely share the info in case it’s possibly helpful to other whisky folk, and I hope to learn more about long-term storage from science in the future.
Tanks of food-grade argon are widely available to rent from gas suppliers (used by automotive and welding shops, medical and dental facilities, manufacturers, etc.). A small “Q-size” cylinder is approx. 31″ tall by 7″ wide, and the argon lasts a long time (2-3 years of daily use by our family, plus monthly use by a whisky club). Price will vary by location. It costs us approx. $60 CAD ($45 USD) to fill with food-grade argon (once every 2-3 years), and approx. $100 CAD ($75 USD) per year to rent the steel tank. The supplier can sell you a pressure regulator (gas flow rate) and a few feet of small diameter rubber hose (one-time purchase approx. $150 CAD or $115 USD). Place the hose into the bottle just above the liquid surface and turn on tank (displacing air with argon). If you set the regulator to 5 PSI, it will fill an empty whisky bottle in approx. 9 seconds. Just guess at the head-space. Bottle looks half empty, 4.5 seconds. The argon will flow out the hose for a couple seconds after you turn the tank off, so roughly 3 seconds for a half bottle, and 1 for a quarter bottle. Cork or close. Easy.
But again, as Eric correctly noted, even though it’s highly-pure inert gas (commonly used in the food packaging industry), we haven’t studied the long-term effect, if any, on whisky.
You also have to be careful to store the tank properly (which you can do in a home, consult your supplier). You also have to use it properly, and always remember to turn it off after use (argon is colourless and odourless, suffocation can occur in small or poorly ventilated spaces, again consult your supplier – I’m just a whisky drinker).
Sláinte : )
Thanks for the detailed and thoughtful comments. Appreciate you adding to the discussion here.
The science behind aeorosol/gas interactions is certainly very interesting (and very much unsettled in the case of a whisky bottle). You raise some good ideas, although the technical testing side is something I would have to leave to others more qualified to experiment with. For now, I will continue to put my stock in properly-controlled, blind sensory testing – but hopefully we see continued activity on both fronts.
Correction: “…1 for a quarter-empty bottle.”
I would add that argon is inert, whereas carbon dioxide and nitrogen are not, and are common in aerosol spray “blanket layer” products.
Also, it’s my understanding that “blanket layer” products introduce only a small amount of gas into the bottle head-space. Air remains. If diffusion mixes the gases, oxygen is again in contact with the whisky. In contrast, argon injected from a pressurized cylinder displaces the head-space air. Argon remains.
Finally, if Eric is correct in stating that oxidation is “unlikely to be contributing in a major way to changing characteristics over time”, then the use of inert argon to displace the air may not be useful. (Can air react with whisky in any way other than oxidation? I don’t know.) If instead of oxidation, it is the loss of ethanol and aromatic/flavour compounds each time the head-space is replaced (through pouring a dram) as Eric posits, then his recommendation regarding small bottles, proper caps & liners, and minimal head-space would appear to be the only practical option for long-term storage. Our use of argon has been about minimizing reactions with air. I know, I know, f— it just drink ‘em up : )
Again, thanks for the great article.
“For now, I will continue to put my stock in properly-controlled, blind sensory testing…” Agreed. I look forward to reading your article updates.
Are you aware if anyone is testing cylinder-dispensed argon? I know of collectors who use this method, and experienced reviewers such as LiquorHound, but I’ve never read about anyone testing anything other than aerosol sprays. Have you please?
Also, are you reasonably confident that change over time is likely not about reactions with air? If yes, I need to consider abandoning argon and switching to the small bottles method you described.
Eric, are you aware if anyone is testing cylinder-dispensed argon?
Also, are you reasonably confident that change over time is likely not about reactions with air?
Thanks.
I don’t know if anyone who is running these kinds of experiments is testing that specifically – it is not something a typical enthusiast would have access to.
And to be clear, I would expect that exposure to air would induce changes with time. The problem is we don’t know how long that would take before it would be detectable (and studies would need to carefully control other variables that could confound, such as storage conditions). From the studies cited on this page, there is no evidence people can detect any changes at up to a year when sampled blind.
I have had whiskies that have been opened for more than a decade, and they all tasted perfectly fine (some were outstanding). I didn’t have matching unopened bottles to compare to of course.
Thank you
So, experienced tasters couldn’t detect any effect of bottles being open for half a year or a year. What does that tell you about the “rule” of letting a dram stay (“settle”, “open up”, etc.) for some minutes (“as many minutes as the number of whisky age years”) before making the first sip?
On second thought, maybe that time is required for the volatile components to fill up the air headspace in the glass…
Yes, that’s what I would expect as well. With properly-shaped stemware (i.e., small tulip-like shape), I find the aromas do increase after several minutes in the glass. It also seems to me that a bit of water helps with this too.
Thank you for the interesting summary. I am a scientist searching for a dissolved oxygen sensor for near pure alcohol samples, this is more challenging than you would expect but i did stumble across this review.
I have a couple of comments.
section 2.4 inert gas. i agree that long term study would be advised however it is implied that the “propellant” would need to be studied. i am very familiar with using nitrogen, we use it regularly to inert the head space of samples and the gas itself under pressure is the propellant; or in other words no other propellant is present.
Section 3. Interesting results on the blind study, i would be curious to know if the bottles were stored exposed to natural light during the 1 year period specifically UVB. The use of head space GC and GCMS is great for volatile component study but not for non volatile molecules which is where i would expect the results might be different. the use of HPLC DAD or LCMS QQQ would be more appropriate for such a study although more involved
Thanks for your comments Mark, very helpful, and I appreciate the insights.
In terms of the propellant, your point about nitrogen under pressure is well taken. But I am uncertain as to what is being used in those small cans of commercial wine-preserver spray, as their composition is not disclosed. I am under the impression that butane or propane is commonly used for spray cans. So my point is that whatever may be emitted from those cans must be directly studied.
Interesting compilation of information. However, I stumbled into this discussion while doing a search on cork degredation over time and my personal experience does not support the advice in 1.1 ie storing the bottles upright. My collection has for most of its life been stored in total darkness, in the original packaging, in a cool temperature controlled basement. Stored bottles range from 5 to 20 years since purchase and I have had numerous corks, while appearing to be in good condition, crumble when opening. Not very impressive while opening a bottle with friends. Which is why I’m still searching for a solution to long term storage that actually works.
I understand your frustration. But the issue is with using natural corks to seal whisky bottles in the first place. Corks will degrade eventually, and all enthusiasts will come across such bottles sooner or later. Discussion forums are full of threads about how to remove broken corks (use a cork puller not a corkscrew) and how to remove cork bits from a bottle (pour into a decanter using a funnel with cheesecloth). But the advice in 1.1 is absolutely correct – you must store a whisky bottle with a cork upright, or you will rapidly accelerate its degradation, breakdown, and tainting of the whisky.
There is no panacea solution here, as twist caps have their own issues (especially the cheap foil or pastic ones in use by the drinks industry, which wear easily and can leak even while still factory sealed). But robust polycarbonate twist caps, with thick threads, well matted, with solvent-resistant polycone inserts are in wide use in the solvent industry. It just isn’t what consumers are used to.
Wouldn´t a relatively low temperature around 10 – 12 ° C be the best, due to inertia of molecules with lower temperatures? Especially under the aspect, for example, evapouration through slight vibrations over the years could be prevented, since much-driven roads or old wooden floors will always slightly vibrate and very slightly move the liquid, opposed to total isolated standstill.
But in general, isn´t lower equalling better for long term storage?
And second, wouldn´t many layers of Parafilm resolve the problem of gas-permeability? Sine Parafilm is such a nice matrial to “work with”, someone explained that by using many layers, with one or another not “activated” by pulling, could work as gas-permeable barrier.
In general, storing at low temp is always better than at higher temps. But whisky is extremely stable when sealed from air, so temperature storage conditions are not likely to be an issue over the span of a person’s drinking years. As the studies here found, temperature fluctuations are more of an issue – but again, only at extremes.
And yes, parafilm would certainly help limit gas permeability. But parafilm is not gas impermeable – and is in fact more liquid impermeable than gas (which is why I recommend it for transport, but not regular storage if you have a good fitting enclosure). That is why multiple layers is better – but still not perfect. Note that you do need to stretch it somewhat to get it to hold. Again, there are no absolutes here, just varying degrees of sealing.