Here’s the thing: alcohol is volatile—it wants to party and join the air. If you leave a bottle of liquor open for several months, the alcohol percentage can drop by a tiny fraction, like 1% or 2%. Your brain might not even notice, unless you’re a super-taster with a PhD in spirits. But what you will notice is the flavor. Those delicate aromas—vanilla, oak, fruit—are the first to bail. So the drink might taste “flat” or “off,” but the alcohol punch? Still there, waiting to knock you sideways.
Think of it like this: you’re throwing a party, and the DJ leaves early. The party still happens, but the vibes are weird. Alcohol’s the same—the potency hangs around, but the fun flavors might ghost you.
Does This Apply to Beer? (Asking for a Friend)
Beer’s a different beast. If you leave a can of beer open overnight, it goes flat and gross—the carbonation escapes, and the alcohol doesn’t change much. Sure, some ethanol can evaporate, but it’s such a tiny amount that you’d need to leave it out for days to even notice. And by then, it’s a science experiment, not a beverage. Pro tip: if you’re doing a “leave the beer out” experiment, just drink it already. Your future self will thank you.
Side note: Don’t leave an open beer in the sun for a week unless you want skunk juice. Trust me, I’ve been there. It’s not a good look.
Unsealed Alcohol: Does Potency Fade Over Time? | CyAlcohol
