Due to improper storage
And it is that a pantry or a sideboard in the living room is not the most suitable place to store wine. Light, temperature, humidity, position, odors, all of this affects and heating can become your worst enemy.
The ideal is between 12º and 16º, 80% humidity, lying down and as far as possible from the sun's rays.
Also, always keep in mind that a dry cork is the first sign of wine deterioration.
What should it never be done:
Sink the cork. This is going to splash a lot because of the air pressure that is going to be generated inside the bottle. This can alter its natural flavor and properties. Straining it can dull the feeling. Of course, it is better to strain it with a cloth strainer or the paper filters of the coffee maker. Even so, it is still not the best solution. There are others much more effective.
What it should be done:
Very measured movements carefully and delicately and using a special corkscrew. His name is Ah-so. You just have to insert the sheets between the glass and the stopper. First the long one, then the short one, turn, pull and that's it!