Tartrate, Potassium
Potassium tartrate promotes the crystallization of tartaric acid salts when cold-treating wines. Recognised by the OIV, potassium tartrate is permitted for use in grape wine in over 50 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): Dipotassium tartrate, Algol
CAS Number: 921-53-9
E Number: 336
INS Number: 336
International Organisations
Codex Alimentarius
-Classification, Food Category, Functional Class and Recommended Usage is not available at this time.
International Organisation of Vine and Wine (OIV)
-Classification, Food Category, Functional Class and Recommended Usage is not available at this time.
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, Postassium tartrate is used: To promote the crystallization of tartaric acid salts when cold-treating wines.
Usage in Winemaking:
Tartaric acid is naturally occurring in grapes and adjusting the acidity of must and wine is an important part of the winemaking process. The addition of acid to juice, must or wine will decrease the pH and increase the Titratable Acidity (TA) of the wine. The low pH will make SO2 more effective which will help prevent oxidation and bacterial infections, will increase colour intensity and ageing potential of the wine.
Sometimes a must will have a TA that is too low, and this can be raised with potassium tartrate. Due to the presence of large quantities of solids in red musts, less of the salt will be needed than for whites. It is helpful to add a fraction of what is estimated to be needed, dissolved in some juice and well mixed. The must can then be re-tested and adjusted accordingly.
To illustrate:
- A 1.0 g/L addition of Potassium Tartrate will increase the TA by about 1.0 g/L and will decrease the pH by 0.1 unit. In a must for making a white wine, the TA should be roughly in the range from 7 to 9.5 g/L, but can go higher.
- In musts for dessert or sparkling wines, the TA can be well over 10 g/L. In red wine musts, TA should generally be in the range from 6 to 8 g/L.
Additionally, potassium tartrate is added to wine to inhibit the formation of potassium bitartrate crystals which are commonly formed in bottled wine. The presence of potassium bitartrate crystals in wine is not a safety or wine quality issue but rather one of the aesthetics.
See FIVS technical papers for more information - click here.
