Save this one, or remember it will stay in the growing Resources tab...I can promise it will come in handy at some point.
First, you should know that a bad bottle of wine will not make you sick, unlike eating spoiled beef or undercooked chicken. However, bad wine can be much harder to detect. Like death and taxes, flawed wine is unavoidable but you can do a few things to limit your risk.
Shop at places where they take care of the product. Does the store feel hot? Is shelving bathed in sunlight? Light and heat are mortal enemies of wine. If the shop is hot (not just warm) or has wine located in places the sun hits for long periods of time, maybe you should shop elsewhere.
Damage can happen before wine reaches your favorite retailer or restaurant. Importers sometimes ship without proper temperature control. Although this rarely happens anymore, too many wholesalers do not care for their product properly. There is a wholesaler in town that routinely loads their trucks before the sun sets and parks them in their lot overnight. Even responsible companies do not all have refrigerated trucks. Check bottles for signs of leakage or seeping around the foil or neck. Be sure to avoid wines with corks that extend beyond the bottle. That is a sign of heat damage (or freezing - not an issue in New Orleans) because the liquid expands and can force the cork out a bit. Also look for low fills in any bottles you might be purchasing - this exposes the wine to more air and may have oxidized the wine.
Responsible retailers and restaurateurs will keep you from ever seeing or experiencing these problems but it doesn't hurt to be aware of them.
Now the real challenges begin:
Pay attention to the cork when you remove it. Are there wine stains along the length? (Another potential issue from exposure to heat). Are there tartrates (small crystals) stuck to it? This is not a sign of a bad wine just of one that was not cold-stabilized, most likely. For tartrates or sediment, just pour slowly and avoid agitating the bottle and you will only have some in the last glass. You can also filter or decant the wine - more on that another day.
Go ahead and smell the cork. I know, everyone tells you it only makes you seem pompous but sometimes the cork smells like a corked wine, i.e. wet newspapers or cardboard, and that tells me to be suspect of the wine. The cork, no matter how moldy, crumbly, wine colored or corked-smelling does NOT mean a wine is bad. You still need to try the wine. Think of some washed-rind cheeses...if you ran away from the wet sock aroma without trying the deliciousness within you missed out.
Sometimes a wine can be a bit funky when you first open it. Remember it is a living thing. Think back to the last long trip you took. Were you at your best immediately after getting out of the car or off the plane? I know I'm not. I need some time to acclimate and stretch my legs. Same thing for wine. Some musty flavors 'blow off.' If the wine is corked, the unpleasant aroma tends to get stronger with exposure to oxygen, so you'll figure it out.
[Hint: If you don't know what a corked wine smells like ask your retailer if there are any available to smell. Sometimes a customer has returned one but the wholesaler has not yet picked it up. You'll never forget it and will be able to recognize it forever after].
Some things that won't blow off are wine that has become vinegar - I think we can all tell when that has happened - and wine that is re-fermenting in the bottle. The latter means you have still wine, by design, that is now sparkling. Be careful here, some wines are lightly bubbly on purpose, even without a telltale sparkling wine cap. Unintentionally effervescent wines tend to have a funky note and uneven, unintegrated bubbles - they can even be a bit harsh in the mouth rather than lively and pleasant.
Pour the wine. If it is a white wine, is it orange or even brown in the glass? That is a sign of oxidation and you will be unhappy with the wine (although there are some wines made this way on purpose, you are unlikely to happen across one by accident).
Red wines gradually fade in color and become brickish or even brown in the glass but that shouldn't happen to wines on retail shelves. If the vintage is more than four or five years before the current year, you should inquire about it before purchasing. [Note: Some producers hold their wine back longer than others before releasing them. Italy and Spain are famous for this, especially in Tuscany - think Brunello and Chianti Riservas - and Rioja, again Reservas and Gran Reservas].
Smell and taste, if you have concerns or are unsure about the wine, be sure to leave it alone for a few minutes - then give it a second chance. Some of these can be considered quirks, like the friend who has some habits you might prefer weren't shared. Some people will find those quirks endearing, perhaps even a bonus, but they are fewer in number. Earthy, funky flavors can be part of a good or bad bottle of wine.
Sulfur is sometimes used during bottling and can result in a matchstick aroma when the wine is first opened. This will fade relatively quickly.
Things that won't fade at all, and may become more pronounced are volatile acidity (VA) and brettanomyces (brett). The former can add complexity if there is not too much of it. With more VA present, the wine smells of nail polish or band-aids. While some consumers will tolerate (enjoy?) wines with this fault, I am not one of them. The latter is a component I sometimes treasure but, again, it can overwhelm the wine. It adds a wild, animal or even barnyard funk to the wine. The French might call it sauvage - though each of those words I just used can also be accurately used to describe wine without any level of brett. Some wines have built reputations and garner high prices because of the presence of brett, others fail to achieve distribution beyond their winery...or their drains.
By far the most frequent issue consumers encounter these days is the presence of 2,4,6-Tricholoranisole (or TCA). This is what you smell in your wine when it is corked. It is the reason for the creation of, and embracing of, screwcaps. It is the thing wineries fear more than anything but weather. Why? Because the incidence of cork taint is much higher than the number of bottles returned. That means huge numbers of people experience an unpleasant tasting wine and do not realize it is flawed. That means they will likely not buy the wine again and might tell lots of others to avoid it as well. [Note: For years before screwcaps became (mostly) accepted by consumers, lots of wineries shipped wine to events, reviewers, etc. with that seal, avoiding the risk of corked bottles in those important venues].
Moldy cardboard, wet newspapers that have been stacked up for a few days, etc. are the telltale aromas. They can be faint but it is an unforgettable sense memory once you have experienced it. Oxygen will make the flaw more pronounced, so leave the bottle for a minute or so and try again if you're unsure. If you are in a restaurant, don't hesitate to have your waiter or sommelier taste it as well. They should know the wine and be able to recognize any issues. And be happy to supply a replacement if there are issues. [Note: This is why sommeliers taste your wine sometimes. They want to be sure you are receiving a proper version. Chefs do this all the time in the kitchen, we just don't see it].
One last note, just to remind you that wine can be infuriating and that nothing is black and white. Wine displays various levels of being corked. Some can be smelled across the room while others may go totally unnoticed. It's not like a microwave experience where you have a sound wine and 15 seconds later it is corked and undrinkable. It is much more like crock pot cooking or erosion...or the coming down with the flu.
The most insidious moment in the corked process is the earliest stage. From my experience, I believe that corked wines just heading in that direction are sometimes simply more mute. The cork might have the faintest trace of TCA but the wine smells fine...it just doesn't show very much fruit or character. I have experienced a few of these bottles and I only knew something was amiss because I had tasted another, sound, bottle recently. Don't get too worked up about this (it is a very infrequent occurrence) but I felt I needed to share what I believe to be the full story.
Did I miss anything? Anyone want to add, clarify, debunk?
Coming Soon: Now you know you have a bad bottle...what do you do with it?