Every spirit is subject to evaporation, oxidization and slight differences in flavor if notstored right. So, if you’re wondering why your rum tastes different after you left itopen and unattended for over 6 years, chances are a good portion of it has gone withthe wind.
The best way to go ahead with storing your rum is to keep the bottle away fromdirect sunlight (to avoid evaporation) – which is the standard rule for just about anybeverage, to be honest. So, it would be advised that your precious rum bottles bestored in a cool, dry, and if possible, dark place to preserve its flavor for as long aspossible.
(And no, storing away your 10 year-aged rum bottle for 5-years, doesn’t make it a 15-year aged rum. That’s the job for rum barrels.)
Unopened rum bottles can be stored almost indefinitely, because rum is a stableliquor with a high ABV that remains as it is if stored right.
Once opened though, the rum should be used within 6 months to 2 years dependingon the type of rum.
If it’s pure rum with no additives and flavors, it can retain its taste profile for around2 years. On the other hand, flavored rum has the sugars and spices that can interactwith oxygen once the bottle is opened.
So, you could seal back the bottle as tightly as your sober strength permits, but youwould still notice slight shift in color, flavor, and potency within 6 months.
Not that we expect you to leave behind a bottle unfinished, but if you happen to doso, do keep these factors in mind.