My best friends live in the same old house he grew up in as a kid. His father or grandfather was a wine maker back in the 50's. Last summer while moving stuff around to install some surround sound speakers one, we moved piece of furniture that turned out to be hiding this small rack of 50 year old wine homemade bottles...full.
Most of the had written labels were worn off, but one of them was labeled pear.
After chilling it for a couple days I came back and we sampled it. It was amazing...even though it had turned the color of raisin juice (probably since the may have used raisons as yeast) it was amazing...it was no longer like a wine, more like a pear brandy....Same color, same raisin and caramel notes, and really really smooth. It was intensly Pear like, like concentrated. It was a tad oxydized, but still amazingly drinkable.
I keep forgetting to get them to open more of them.
I don't believe necessarily that it has gone bad. It wont hurt you, and really, you'll know probably by sniffing it, or at least tasting a sip how it is.
I NEVER pass those opportunities up these days. You never know what magic you MAY find.