I brewed and bottled an English Ale in August, and, after a few weeks in the bottle, promptly drank most of the 5 gallons.
However, I'd heard some advice to leave a few bottles for a few months to see how it evolves over time. Yesterday, I cracked open one of the bottles, and it certainly had evolved, but for the worse.
In fact, this brew had become somewhat cloudy, and had a distinctive taste that I could best describe as dusty and moldy. From what I understand, a moldy malt can yield a moldy brew, but this seems doubtful in my case, since I had plenty of this beer and it was delicious until now.
Was it just an anomaly? Or did something grow over time? Perhaps I capped poorly? Or maybe this bottle just wasn't thoroughly clean?