Not all wines are meant to keep for a long time and drink it later. There’re some factors that will alter its flavor, for example if it had some kind of contact with air for a long period of time. Here a few signs that indicate a good wine bottle has gone bad.

The Look of the bottle
The first thing to watch Is the cork, if you noticed that its slightly out of bottle it means that the wine will start to deteriorate and will stop aging, according to Jordan Salcito, a good tip is to smell to bark and if its smells like a “wet dog” you should throw it away immediately. Color Change if the red wines change from purple to reddish marron and in the white clear white wines change to gold a change in the color indicates that something is wrong

Strong Odors
There is a bacterium in wine that converts the alcohol into an acetic acid, it’s more like a vinegar. Suggestion to detect it is that if the liquid has a smell similar to sulfur or acetone or if the aroma of a wine is moldy it means that it does not work.

Sweet Flavors
This means that if the wine bottle tastes like a sweeter liquor, the riper the grapes are, the more sugar they have., it has been overexposed to heat and, therefore, you cannot drink it.

Effervescent
The chemical process that consists of the reaction of an acid with sodium bicarbonate or a sodium bicarbonate, happens when the grape is fermenting. If its flavor is gaseous and it is not a sparkling wine you shouldn’t drink it.

Vía Food & Wine