Copper Sulphate
Copper sulphate bonds with hydrogen sulfide to precipitate out of fermenting grape must and wine. Recognised by the OIV, copper suphate is permitted for use in grape wine in over 45 countries worldwide.
Copper sulphate is used in processing wines possessing so-called reduction “tastes” due to the presence of hydrogen sulfide or volatile thiols. The copper sulfides thus formed precipitate and should be removed from wine. This product must be used in compliance with copper sulfate pentahydrate limiting quantities; furthermore, there are statutory limits restricting the copper content in wines.
Melting point: 110 °C with water loss. An aqueous solution with ammonium hydroxide (R) produces a dark blue copper tetramine compound. A solution acidified with hydrochloric acid and a barium chloride solution (R) produces a white barium sulfate precipitate.
For further substance information, please see the International Oenological Codex.
Synonym(s): Blue Stone, Copper Sulfate
CAS Number: 7758-98-7
E Number: 519
INS Number: 519
International Organisations
Codex Alimentarius
-Food Category, Functional Class and Recommended Usage is not available at this time.
International Organisation of Vine and Wine (OIV)
-Food Category Wine (grape) Functional Class Defect Corrector Copper sulphate, pentahydrate : processing aid Recommended Usage (International Code of Oenological Practices – Annex: Maximum Acceptable Limits) Amount used in the treatment: 1 g/hl
FIVS
Classification Category 2 – Naturally occurring in grapes and treatment residual in wine
Recommended Usage
Please refer to the Joint FAO/WHO Expert Committee on Food Additives’ (JECFA) “acceptable daily intake” (ADI) for recommended usage.
As outlined in the OIV’s International Code of Oenological Practices, Copper Sulphate is used:
Copper sulfate is used in processing wines possessing so-called reduction “tastes” due to the presence of hydrogen sulfide or volatile thiols.
Usage in Winemaking:
Copper sulphate bonds with hydrogen sulfide to precipitate out of fermenting grape must and wine. Residual copper will remain in solution and attention should be paid to regulatory limits. Copper sulphate is also used to ‘pop’ the fruit aroma of a wine prior to bottling.
See FIVS technical papers for more information - click here.
