How to know if your wine is bad in 3 steps or points:
The cork is the first indicator of a bad wine: it should be as clean as possible, especially for wines that do not have a long shelf life. The cork should not fall apart or present defects such as perforations, black parts or mold.
The smell of the wine: once we detect that the cork does not come well, we proceed to smell it, as well as the wine. If we smell wet cardboard, sulfur, vinegar, onion or garlic, acetone, mold or something like that, the wine is damaged.
The color of the wine is another indicator that the wine is bad and generally goes hand in hand with its bad smell. When it is dull, cloudy or with brownish tones, it is likely to be damaged.