Potassium Bitartrate/Potassium Hydrogen Tartrate
After fermentation, young wines are usually saturated with potassium bitartrate. Recognised by the OIV, potassium bitrate is permitted for use in grape wine in over 40 countries worldwide.
This addition of potassium hydrogen tartrate, commonly called potassium bitartrate, promotes the crystallisation of tartaric acid salts when cold-treating wines.
This is an anhydrous monopotassic salt of L(+) tartaric acid C4H5O6K. It is found in the form of white crystals or white granulated powder having a slightly acidic taste. For further substance information, please see the International Oenological Codex.
Synonym(s): Tartaric acid monopotassium salt
CAS Number: 868-14-4
E Number: Not available at this time
INS Number: Not available at this time
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 Stabliser Potassium hydrogen tartrate: processing aid Recommended Usage (International Code of Oenological Practices – Annex: Maximum Acceptable Limits) Not provided
FIVS
Classification Category 2 – Naturally occurring in grapes and treatment residual in wine
Recommended Usage
Not available at this time
As outlined in the OIV’s International Code of Oenological Practices, potassium bitartrate is used:
To promote the crystallisation of tartaric acid salts when cold-treating wines.
Usage in Winemaking:
Tartaric acid is the most prominent acid in wine, with the majority of the concentration present as potassium bitartrate. After fermentation, young wines are usually saturated with potassium bitartrate. When a wine is cooled the solubility limit is exceeded and the ‘excess’ precipitates out as crystals. The lower the temperature to which it is cooled the more crystals will form, until the saturation equilibrium at that temperature, is reached.
If bottled wine is subjected to a lower temperature than it has experienced previously, then tartrate crystals may appear in the bottle, looking like tiny pieces of broken glass. The crystals are of course harmless but their presence is generally undesirable to consumers. To reduce the time for the stabilisation process a small amount of very finely powdered potassium bitartrate is added to the tank and roused (continually for one hour) into the cold wine. This ‘seeds’ the wine and provides a very large surface area for the excess tartrates in the wine to precipitate onto.
See FIVS technical papers for more information - click here.
