Appropriate humidity level 

The bouquet of a wine develops through a reduction process in the total absence of oxygen, which means that the cork must be perfectly air tight. To preserve this sealing over time, the bottle must be stored on its side so that the cork remains in contact with the wine. Furthermore, the average humidity level in the cellar must be kept above 50%.
If humidity drops below 50% for too long, the cork is likely to dry out and the wine could begin to seep through the cork. A significantly higher humidity level over 80% will not damage the wine, but it can alter labels. A real wine cellar must be conceived to constantly guarantee an average humidity between 50% and 75%, while preventing the formation of stagnant water likely to develop bacteria and unpleasant odours.