International Code of Oenological Practices

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Alcoholic fermentation

II.2.3 Alcoholic fermentation


Transformation of grape sugars into ethanol, carbon dioxide and secondary products.

Objective :

Production of wine.

Prescriptions :

a)        Fermentation can take place:

  • Spontaneously by means of yeasts naturally present on the skins of the grapes, in the musts and in cellars ;
  • By inoculation of must or of crushed grapes with selected yeasts, before or during the fermentation (see II.2.3.1 ‘Inoculation with yeasts’). 

b)       The progress of the alcoholic fermentation can be influenced:

  • By addition of activator substances (see Activation of alcoholic fermentationII.2.3.2 and II.2.3.4 ‘Treatment with yeast ghosts’):
  • By aeration of the crushed grapes or of the fermenting must (see Aeration II.2.3.5);
  • By control of the fermentation temperature as a function of the type of wine desired (see II.2.3.6 ‘Interruption of alcoholic fermentation by physical processes’);
  • By all other acceptable interventions aiming to favour alcoholic fermentation, to restrain it or to stop it.


Recommendation of OIV: