At Christmas, I bought a few bottles of cider on special. Unfortunately, they tasted bad, the flavor was a bit sharp and had a bad aftertaste. We had to mix it with other beverages to make it palatable. It was the embarrassment of the holiday season.
In April, I saw we still had a bottle of the cider in the wine cabinet, so I put it in the fridge. It has been in there until this weekend. We opened the bottle preparing ourselves for punishment, however the cider was excellent! I am trying to figure out what happened! I don’t know a lot about the process of making cider. Were the other bottles opened to early after production? Was this bottle a different batch? It is a mystery that will haunt me.
So from what I’ve seen, and made, looks like a) you bought it not fully fermented and the other bottle had more time to ferment when you left it in the cabinet or b) the two bottles came from a different batch like you said and you just got unlucky with the first.
My home made wines had the same thing happen. The older they got, the better they got. I think that over time some of the brutal tastes and chemicals break down and you’re left with a smoother drink.