The mannitic disease, which is due to high temperatures during fermentation and lack of acid in the must, is rarely of serious consequence in temperate countries.
In these cases the mannitic fermentation had obviously not developed to any extent, and small quantities of mannitol appear to exercise no prejudicial effect on flavour.
It has been found, for instance, that in the case of the mannitic disease the action of the micro-organism may be checked, or prevented altogether, by bringing the acidity of the must up to a certain level by the addition of a small quantity of tartaric acid.