The Proper Wine Etiquette for Being Served, Serving and Tasting
When the bottle of wine is presented, it is proper wine etiquette to examine the label to be sure the producer and vintage match what you ordered. The restaurant might be out of a particular vintage and substitute a different year. It may not make a difference to you. However, if you wanted to enjoy a wine you have experienced previously and a substitution was made, there will certainly be a difference. In such case, you may wish to order a different wine. A different vintage could be trivial if it's a simple Cotes du Rhone but significant if you were ordering a 2000 Bordeaux and received a 2002 instead.
Check that temperature is satisfactory. White and rose wines are best slightly chilled, at 50 degrees. Better to be too cold than too warm for either red or white. It isn't improper wine etiquette to request an ice bucket to chill both whites and reds; and don't hesitate to do so if that is what you would prefer. However, the conventional wine etiquette of placing the bottle in an ice bucket can compromise your experience; fine white wines will release more texture and bouquet as they warm up in the glass; try it. The exception to this would be when drinking a modest wine on a hot day. A red wine brought to the table slightly chilled indicates good storage; you can always warm up the wine by cupping the glass in your hands and swirling.
When the bottle of wine is opened, it is proper wine etiquette for the sommelier to present the cork to the person who requested the wine. The vintage on the cork should match the vintage on the bottle. Visual inspection of the cork often reveals little; a pristine looking cork can stopper a bad wine and a delicious wine can come from a cork that disintegrates as it's removed.
Sniffing the cork may reveal earthy aromas but keep in mind you're smelling the bark of a tree. Many a bottle has been mistakenly returned because there is mold on the top end of the cork. This has no effect on the wine; it simply means the bottle was aged in the producer's damp cellar prior to release, which is a good thing.
Swirl & Sniff
The proper wine etiquette procedure will dictate that the sommelier will then look to pour a small amount of wine for the person ordering the wine. Gently swirl the wine in the glass to release the aroma, give it a sniff, and then taste it. If there is an objectionable or unexpected aroma, the sommelier should recommend further aerating the wine in which case the "off odor" will dissipate, or replacing the bottle. Unfortunately, it is sometimes difficult to differentiate between funky aromas that are inherent in certain wines and similar smells that are symptoms of a defect. Proper wine etiquette is to consult with the sommelier. If you smell a moldy aroma reminiscent of a "wet basement" the wine is "corked", meaning that it has been tainted by a moldy cork. Unfortunately, the mold is not visible nor does the cork necessarily smell moldy. Since there are varying levels of cork taint, a corked wine can be overtly stinky or the fruit character is slightly muted. If you perceive this to be the situation, send the bottle back immediately. If you're not quite sure, politely ask the sommelier for an opinion, all in keeping with proper wine etiquette.
There are two reasons to decant a wine: (1) to separate the wine from the sediment in the case of a 20 year old port or red wine; or (2) to open up and soften the tannins of a young red wine. Decanting and swirling the wine in the glass will do a far better job than opening the wine two hours prior and letting the wine "breathe", which is not practical in most restaurant settings. White and sparkling wines rarely need extra breathing time. It is not proper etiquette or an acceptable practice to return a wine simply because you do not like it as much as you thought you might.
After you have taken a sip, the proper etiquette is to nod, say "thank you", "it's fine" or some signal for the sommelier to begin pouring. Wine etiquette dictates that the glass is filled about one third full to allow enough space to swirl the wine. Sparkling wines pour along or against the side of the glass to preserve the bubbles.
Wine etiquette may seem unnecessary, but following the proper wine etiquette will enhance the overall wine drinking experience. Wine etiquette and all its subtleties are intended to slow the experience so that the product before you can be fully appreciated and enjoyed.