Diseases Prevention is the key In a good cellar more water should flow than wine. This is an old saying , but it is still true: wine diseases are almost always caused by bacteria (lack of hygiene). There are two main types: aerobic and anaerobic. Aerobic diseases are due to bacteria which develop in the presence of a lot of oxygen. The most well-known are 'fioretta' (a white cobwebby veil over the surface of the wine), 'spunto' (acetic bacteria which attack the alcohol) and 'acescenza' (the wine turns to vinegar). The anaerobic diseases, on the other hand, are due to bacteria which develop in the absence of air. The best known are 'filante' (the wine becomes viscous and oily), 'girato' (affects wines weak in alcohol), bitterness (old red wines with low fixed acidity) and bittersweet (which affects young reds from overripe grapes). It is unusual to find a 'sick' bottle on sale. Usually the producer notices the problem and acts on it. It is easier to find a bottle affected by a loss of colour and clarity, phenomena which can happen after the bottles go on sale.