Hi there, If you're wondering how long beer can stay good in the fermenter once the airlock has dried out, the answer is apparently "a surprisingly long time"... Beginning of this year, I brewed an ale that I just couldn't be bothered bottling... I was just tapping it out of the fermenter (I have those plastic buckets with spigots), then once it bottomed out, I kept planning to clean it out tomorrow. Fast forward many tomorrows, to late November. The airlock has been dry for months. Having finally decided to face the unspeakable horrors that have spawned in that bucket during all those months, I gingerly open the lid and peek inside... and find it perfectly fine! There was no slime, gunk, moss or filth, just normal bottom-of-the bucket stuff. I didn't taste it, but it smelled remarkably like "fresh" beer. Now you're probably wondering whether that says more about my standards of brewing than the preservative powers of beer... I suppose there may have been a layer of CO2 covering the liquid? No idea if that's realistic. But anyway, looks like a bit of exposure to air won't ruin your brew.
I think your discovery definitely involved alcohol! Check it out...take a sip, if it really stinks, spit it out...have a chaser nearby! What was your expected ABV in the brew?
I'm a curious sort, I've had beers I've known were dumpers and tasted anyways. Like @Ward Chillington said, with that I'd just have a whiskey chaser at the ready in case
So between the alcohol, the carbon dioxide and your starting place with your cleaning, I'd say your deserve today's "ATTABOY" for brewer cleanliness! Have faith,,,,,drink it next time!
I would have taken a taste too, but I'd already placed the whole bucket in the bathtub so with all the sloshing, there was lots of slurry suspended, and it wasn't too practical to sample. Ideally the conditions of this experiment won't be replicated again, but if they do, I'll be sure to check in