International Oenological CODEX

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Potassium D,L-tartrate

COEI-1-POTRAC Potassium D,L-Tartrate

Potassium D,L-2,3-dihydroxybutanedioate

Potassium racemate

COOK-CHOH-CHOH-COOK = 226.3

  1. Objective, origin and scope of application

Potassium D,L-tartrate is a salt used to deacidify musts and wines and to remove excess calcium.

Its use is subject to certain regulations.

  1. Labelling

The label should indicate product purity as well as its safety and storage conditions. It should also clearly state that this is a racemic mixture of the two isomers D and L of tartaric acid, thereby avoiding the supposition that it is the natural L-tartaric acid found in grapes.

  1. Properties

This product is the dipotassic salt of D,L-tartaric acid or racemic tartaric acid K2C4H4O6.

It is found in the form of white crystals or granulated white powder and is highly soluble in water.

  1. Tests

4.1.    Desiccation Loss (volatile substances)

After 4 hours of desiccation in a 105 °C oven, weight loss should not exceed 1 pp 100.

4.2.    Preparing the Solution for Tests

Place 10 g of potassium racemate in a 100 ml volumetric flask and fill to the gauge line with water.

Perform the same tests on this solution as indicated in the monograph on neutral potassium tartaric, including sodium, and observe the same limits.

4.3.    Distinguishing Potassium D,L-Tartrate from Neutral Potassium Tartrate

Proceed as indicated in the monograph on neutral potassium tartrate. No white, crystalline precipitate should form instantaneously.

4.4.    Lead

Using the technique described in the Annex, determine the lead content. Content to be less than 5 mg/kg.

4.5.    Mercury

Using the technique described in the Annex, determine the mercury content.  Content to be less than 1 mg/kg.)

4.6.    Arsenic

Using the technique described in the Annex, determine the arsenic content. Content to be less than 3 mg/kg.

4.7.    Oxalate

Using the technique described in the Annex, determine the mercury content in the test solution (4.2) (The content, expressed as oxalic acid, should be less than 100 mg/kg.)

  1. Storage

Potassium tartrate should be stored in hermetically sealed containers.