Sodium Potassium Tartrate E337
buffering agent, sequestrant — Primarily synthetic (from tartaric acid).
Potassium sodium 2,3-dihydroxybutanedioate tetrahydrate
CAS: 6381-59-5
Factual Regulatory Reference
This database provides factual regulatory information compiled from official government sources. It does not constitute medical, nutritional, or safety advice. Regulatory status varies by country and is subject to change. Always refer to your local regulatory authority for the most current information.
What Is Sodium Potassium Tartrate?
Sodium potassium tartrate (Rochelle salt) is a mixed salt of tartaric acid containing both sodium and potassium ions. Used as a sequestrant and acidity regulator in processed foods, it was historically the first crystalline piezoelectric material discovered (Rochelle salt effect) and is still used in some electronic applications. As a food additive (E337), JECFA set an ADI of 30 mg/kg body weight (tartaric acid group). EFSA reviewed it in 2014. It is approved in the EU and other jurisdictions for use as an emulsifying salt and stabilizer.
? Did You Know?
Beyond food, Sodium Potassium Tartrate is also used in cosmetics, medicine, industrial applications, household products. Its versatility makes it one of the most multi-purpose chemical compounds in everyday life.
In the EU, Sodium Potassium Tartrate has a "quantum satis" authorization — Latin for "as much as needed." This means there's no specific maximum limit; manufacturers use only what's technologically necessary.
Detailed Regulatory Assessment
European Union (EFSA)
Permitted in various food categories
Official EFSA LinkUnited States (FDA)
Regulated as a direct food additive under FDA CFR titles.
Japan (MHLW)
Compliant with Japanese food sanitation law.
Acceptable Daily Intake (ADI)
International Standard (JECFA)
mg/kg body weight per day
European Standard (EFSA)
Natural Occurrence
This additive is not known to occur naturally in significant quantities.
Manufacturing
Produced by neutralizing tartaric acid with a mixture of sodium hydroxide and potassium hydroxide, or by combining sodium tartrate and potassium tartrate solutions. The product crystallizes as the tetrahydrate form. First prepared in 1675 by Pierre Seignette, a French apothecary in La Rochelle (hence the name Rochelle salt).
Applications Beyond Food
Buffering agent in formulations.
Laxative (mild), component in effervescent formulations.
Component of Fehling's solution (chemical testing), silvering mirrors, piezoelectric crystals (historical use in early microphones and phonograph pickups).
Ingredient in some cleaning products.