Sodium potassium tartrate

E number E337INS 337CAS 304-59-6

Used as an acidity regulator — Codex also lists it as emulsifying salt, sequestrant, stabilizer.

Sodium potassium tartrate, historically called Rochelle salt, is an acidity regulator and sequestrant used in confectionery, jellies and processed cheese.

Where it is and isn’t permitted

Status of Sodium potassium tartrate by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1804retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

63 food categories

highest permitted level 30,000 mg/kg

Show every food category
  • 01.1.4 Flavoured Fluid Milk Drinks — 2,000 mg/kg
  • 01.2.1.2 Fermented milks (plain), heat-treated after fermentation — 2,000 mg/kg
  • 01.6.1 Unripened cheese — 1,500 mg/kg
  • 01.6.4 Processed cheese — 30,000 mg/kg
  • 01.7 Dairy-based desserts (e.g. pudding, fruit or flavoured yoghurt) — 2,000 mg/kg
  • 02.2.2 Fat spreads, dairy fat spreads and blended spreads — 100 mg/kg
  • 02.3 Fat emulsions mainly of type oil-in-water, including mixed and/or flavoured products based on fat emulsions — 100 mg/kg
  • 02.4 Fat-based desserts excluding dairy-based dessert products of food category 01.7 — 100 mg/kg
  • 03.0 Edible ices, including sherbet and sorbet — 4,000 mg/kg
  • 04.1.2.11 Fruit fillings for pastries — 10,000 mg/kg
  • 04.1.2.3 Fruit in vinegar, oil, or brine — 1,000 mg/kg
  • 04.1.2.5 — 3,000 mg/kg
  • 04.1.2.6 Fruit-based spreads (e.g. chutney) excluding products of food category — 3,000 mg/kg
  • 04.1.2.7 Candied fruit — 20,000 mg/kg
  • 04.1.2.9 Fruit-based desserts, incl. fruit-flavoured water-based desserts — 1,000 mg/kg
  • 04.2.2.3 Vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), and seaweeds in vinegar, oil, brine, or soybean sauce — 15,000 mg/kg
  • 04.2.2.4 Canned or bottled (pasteurized) or retort pouch vegetables (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera), and seaweeds — 1,300 mg/kg
  • 05.1.1 Cocoa mixes (powders) and cocoa mass/cake — 5,000 mg/kg
  • 05.1.2 Cocoa mixes (syrups) — 2,000 mg/kg
  • 05.1.3 Cocoa-based spreads, incl. fillings — 2,000 mg/kg
  • 05.1.4 Cocoa and chocolate products — 5,000 mg/kg
  • 05.1.5 Imitation chocolate, chocolate substitute products — 5,000 mg/kg
  • 05.2 Confectionery including hard and soft candy, nougats, etc. other than food categories 05.1, 05.3, and 05.4 — 5,000 mg/kg
  • 05.3 Chewing gum — 30,000 mg/kg
  • 05.4 Decorations (e.g. for fine bakery wares), toppings (non-fruit), and sweet sauces — 8,000 mg/kg
  • 06.2.1 Flours — 5,000 mg/kg
  • 06.2.2 Starches — 2,000 mg/kg
  • 06.4.1 Fresh pastas and noodles and like products — 5,000 mg/kg
  • 06.4.3 Pre-cooked pastas and noodles and like products — 7,500 mg/kg
  • 06.5 Cereal and starch based desserts (e.g. rice pudding, tapioca pudding) — 2,860 mg/kg
  • 07.1 Bread and ordinary bakery wares and mixes — 4,000 mg/kg
  • 07.2.1 Cakes, cookies and pies (e.g. fruit-filled or custard types) — 5,000 mg/kg
  • 07.2.2 Other fine bakery products (e.g. doughnuts, sweet rolls, scones, and muffins) — 500 mg/kg
  • 07.2.3 Mixes for fine bakery wares (e.g. cakes, pancakes) — 8,000 mg/kg
  • 08.3.1 Non-heat treated processed comminuted meat, poultry, and game products — 500 mg/kg
  • 08.3.2 Heat-treated processed comminuted meat, poultry, and game products — 500 mg/kg
  • 08.3.3 Frozen processed comminuted meat, poultry, and game products — 500 mg/kg
  • 08.4 Edible casings (e.g. sausage casings) — 2,000 mg/kg
  • 09.2.5 Smoked, dried, fermented, and/or salted fish and fish products, including molluscs, crustaceans, and echinoderms — 200 mg/kg
  • 10.4 Egg-based desserts (e.g. custard) — 2,000 mg/kg
  • 11.6 Table-top sweeteners, including those containing high-intensity sweeteners — 2,000 mg/kg
  • 12.2.2 Seasonings and condiments — 7,500 mg/kg
  • 12.4 Mustards — 5,000 mg/kg
  • 12.5 Soups and broths — 5,000 mg/kg
  • 12.6.1 Emulsified sauces and dips (e.g. mayonnaise, salad dressing, onion dips) — 2,000 mg/kg
  • 12.6.2 Non-emulsified sauces (e.g. ketchup, cheese sauce, cream sauce, brown gravy) — 5,000 mg/kg
  • 12.6.3 Mixes for sauces and gravies — 5,000 mg/kg
  • 12.9.1 Fermented soybean paste (e.g. miso) — 1,000 mg/kg
  • 13.2 Complementary foods for infants and young children — 5,000 mg/kg
  • 13.6 Food supplements — 5,000 mg/kg
  • 14.1.2.1 Fruit juice — 4,000 mg/kg
  • 14.1.2.3 Concentrates for fruit juice — 4,000 mg/kg
  • 14.1.3.1 Fruit nectar — 4,000 mg/kg
  • 14.1.3.3 Concentrates for fruit nectar — 4,000 mg/kg
  • 14.1.3.4 Concentrates for vegetable nectar — 1,600 mg/kg
  • 14.1.4 Water-based flavoured drinks, including "sport," “energy,” or "electrolyte" drinks and particulated drinks — 800 mg/kg
  • 14.2.1 Beer and malt beverages — 2,000 mg/kg
  • 14.2.2 Cider and perry — 2,000 mg/kg
  • 14.2.3 Grape wines — GMP
  • 14.2.4 Wines (other than grape) — 4,000 mg/kg
  • 14.2.6 Distilled spirituous beverages containing more than 15% alcohol — 3,000 mg/kg
  • 14.2.7 Aromatized alcoholic beverages (e.g. beer, wine and spirituous cooler-type beverages, low-alcoholic refreshers) — 4,000 mg/kg
  • 15.0 Ready-to-eat savouries — 2,000 mg/kg
CXS 192-1995 Table One, INS 337and 62 further provisionsretrieved 2026-09-07

What it is made from

Made by neutralising tartaric acid from winemaking residues with both sodium and potassium.

  • Vegan
  • Vegetarian
CAS registry number
304-59-6
InChIKey
LJCNRYVRMXRIQR-OLXYHTOASA-L
PubChem
CID 9357

Every name it appears under

51 recorded names. A label may use any of them.

E number

  • E337

INS number

  • 337

CAS registry number

  • 147-79-5
  • 15490-42-3
  • 304-59-6

As it appears in regulation

  • Sodium potassium tartrate

Other names

  • 2,3-Dihydroxybutanedioic acid, monopotassium monosodium salt
  • ANHYDROUS SODIUM POTASSIUM TARTRATE
  • Butanedioic acid, 2,3-dihydroxy- (2R,3R)-, potassium sodium salt (1:1:1)
  • Butanedioic acid, 2,3-dihydroxy- (R-(R*,R*))-, monopotassium monosodium salt
  • Butanedioic acid, 2,3-dihydroxy-(2R,3R)-, monopotassium monosodium salt
  • Butanedioic acid, 2,3-dihydroxy-, monopotassium monosodium salt
  • C4H4KNaO6
  • CCRIS 3949
  • Co eff pdr
  • E 337
  • HSDB 765
  • INS NO.337
  • INS-337
  • L-(+)-Tartaric Acid Potassium Sodium Salt
  • L-Potassium sodium tartrate
  • L-Potassiumsodiumtartrate
  • Monopotassium monosodium 2,3-dihydroxybutanedioate, (R-(R*,R*))-
  • Monopotassium monosodium tartrate
  • Potassium sodium (2R,3R)-2,3-dihydroxybutanedioate (1/1/1)
  • Potassium sodium (R*,R*)-(1)-tartrate
  • Potassium sodium 2,3-dihydroxybutanedioate (1/1/1)
  • Potassium sodium dextro-tartrate
  • Potassium sodium L(+)-tartrate
  • Potassium sodium L-(+)-tartrate
  • potassium sodium L-tartarate
  • potassium sodium l-tartrate
  • Potassium Sodium Tartrate
  • Potassium Sodium Tartrate (1.5M Solution in Water)
  • Potassium sodium tartrate anhydrous
  • potassium sodium tartrate tetrahy-drate
  • potassium;sodium;(2R,3R)-2,3-dihydroxybutanedioate
  • QH257BPV3J
  • rel-Potassium sodium (2R,3R)-2,3-dihydroxysuccinate
  • Rochelle salt
  • Rochelle's salt
  • Seignette salt
  • Seignette's salt
  • Sodium potassium (dl)-tartrate
  • Sodium potassium L-tartrate
  • Sodium potassium salt of L-(+)-tartaric acid
  • Sodium potassium tartrate
  • Tartaric acid, monopotassium monosodium salt
  • Tartaric acid, potassium sodium salt

Systematic names

  • Butanedioic acid, 2,3-dihydroxy- (theta-(theta,theta))-, monopotassium monosodium salt
  • potassium sodium (2R,3R)-2,3-dihydroxybutanedioate

Hazard reference values

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADI240 mg/kg bw/dayconsumersEFSA FAF2020

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07
  • gsfa retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/sodium-potassium-tartrate.json