International Code of Oenological Practices

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Chemical de-acidification

II. Chemical de-acidification

Classification :

  • Potassium L(+) tartrate: processing aid
  • Potassium hydrogen tartrate: processing aid
  • Calcium carbonate: processing aid
  • Potassium hydrogen carbonate: processing aid

Definition :

Reduction of the acidity and the actual acidity (increase of the pH) by addition of neutral potassium tartrate, potassium hydrogen carbonate or calcium carbonate possibly containing a small quantity of the calcium double salt of L(+) tartaric and L(-) malic acids

Objectives :

a)       See II.3.1.2 ‘De-acidification’

b)       To favour biological de-acidification.

Prescriptions :

a)        The de-acidified wine shall contain at least 1 g/l tartaric acid.

b)       The process of the formation of double salt (neutral calcium salt of tartaric and malic acids) is intended to produce a greater reduction in titratable acidity, when the wine has a high malic acid content and the precipitation of tartaric acid alone does not prove sufficient.

c)        Chemical de-acidification should be performed in such a way that the wines obtained do not lack acidity, taking account of a possible subsequent malolactic fermentation.

d)       The aim of chemical de-acidification shall not be to conceal fraud.

e)       The elimination of excess carbon dioxide can be achieved, if necessary, by flushing with nitrogen.

f)         Chemical acidification and chemical de-acidification are mutually exclusive

g)        The products used shall comply with the prescriptions of the International Oenological Codex.

Recommendation of OIV :