Since returning from Australia, I've been drinking lots of big fun Australian reds, mostly Shiraz and Shiraz blends. The small liquor store that is local to my workplace specializes in Australian wines and has a wider selection than my usual favorite place (Surdyk's). They even carry some Western Australia wines, which I find otherwise very difficult to obtain here.
I'm not ashamed to say that I've taken to buying some boxed Australian wines. They are a good deal, pricewise, and they enable me to drink as much or as little as I please over the course of an evening or weekend. For company I bring out the better stuff, but I don't have company all that often and much of my company prefers the microbrewery beer I have on hand anyway. The boxed wine is just fine for simple pasta or pizza or just with cheese and crackers.
The best of the boxed Shirazes I've found is the Little Penquin brand, which is also the most expensive of what is available: about $22 for a 3-litre box.
Last Friday I picked up a box at lunch and opened it that very evening, so I know the issue was not my less-than-ideal wine storage (inside a cabinet in the kitchen). Instead of the usual big fruity simple taste there was an unappealing bitterness. I wouldn't say it had gone completely to vinegar; it was more that in addition to the wine's flavors there were also these other icky vinegary flavors that made the wine unpleasant and close to unpalatable.
If this had been one small inexpensive bottle I would have written it off, but this was the equivalent of *four* inexpensive bottles. But I didn't trust my own palate here. The next morning I tried a small amount and while it wasn't spit-out horrible it was still icky.
I took the box back to the store, apologetically, claiming I never do this and worried that they would sample the wine themselves and tell me that there was nothing wrong. But they were extremely polite and kind about it. I decided to try the same box of the same brand again, despite my worry that if one box was bad the others in the batch would be bad as well. If this box is bad I know I will be unable ever to purchase it again, at a gut level -- I might not be able to drink any boxed wines at all for a period of time. That's how our bodies work, instinctively, when you eat spoiled food -- the very sight of the same food makes you queasy the next time.
I asked the clerk if this happened much, and she said not often, particularly with the boxed wines, but it does happen. They didn't try the wine themselves, or give me a funny look or anything. They said if this next box was bad to please give them a call. It was simple and quick as can be.
If it had been a single bottle I might have been tempted to try to get it all to turn to vinegar and experiment with it for salad dressings. But four bottles worth? Nah.
Anyway, the exchange was easy. I'm glad, because if it weren't I wouldn't be able to continue to shop at that store.