International Code of Oenological Practices

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Calcium sulfate

II. Calcium sulfate


Calcium sulphate: additive


Addition of calcium sulphate (CaSO4.2H20) to the must prior to fermentation in combination with tartaric acid for the elaboration of liqueur wines.


a)        Produce balanced liqueur wines from the gustatory point of view;

b)       Favour a good biological evolution and good storage of liqueur wine;

c)        Remedy insufficient natural acidity of liqueur wines caused by:

  • climatic conditions in  the viticulture region,
  • oenological practices which lead to a decrease in natural acidity



a)        The use of calcium sulfate is used in combination with lower tartaric acid level

b)       It is suggested to make laboratory preliminary tests to calculate the doses of calcium sulfate and tartaric acid needed to reduce the pH required;

c)        The dose must not exceed 2 g/L of calcium sulfate because it allows to reach the adequate pH 3.2 in the winemaking of these musts and to obtain equilibrated wines even in years of adverse weather conditions;

d)       The residual level of sulfates in wines must not exceed the OIV limit;

e)       The practice should not be done to conceal fraud;

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

g)        Calcium sulfate used must comply with the prescription of the International Oenological Codex standards.

Recommendation of the OIV:

Admitted only for liqueur wines