What is E337?
E337 is Sodium potassium tartrate, a food additive used as an acidity regulator. Made from tartaric acid, which is often recovered from winemaking by-products (see E334). The source is rarely stated. Doubtful unless the source is stated or the product has a halal logo.
Also written as: INS 337, E-337, E 337. INS is the international numbering system used outside Europe, including on labels in Asia, Australia and the Middle East.
How E337 is made and where it is used
This section is food science. The religious classification is explained further down.
Sodium potassium tartrate (also called Rochelle salt or Seignette salt) is a salt of tartaric acid used as a buffer and sequestrant.
It is produced by neutralising tartaric acid, usually from wine by-products, with sodium and potassium compounds.
It is uncommon in everyday foods; it is more often seen in processed cheese, jellies and some bakery products.
What to do
Look for a halal logo, a "vegan" label, or a stated plant source on the pack. If none of these are present, you can contact the manufacturer and ask for the source.
Is E337 vegetarian or vegan?
Not always. E337 (Sodium potassium tartrate) can be made from plant or animal sources, and labels rarely say which. A vegetarian or vegan label on the pack confirms a plant or synthetic source.
Why we classify it this way
Doubtful Made from tartaric acid, which is often recovered from winemaking by-products (see E334). The source is rarely stated. Doubtful unless the source is stated or the product has a halal logo.
Basis: Source or process not stated. It can be made from sources that change the ruling (for example pigs, an animal that was not slaughtered correctly, or alcohol), and the label does not say which.
References
- Does the Tartaric Acid Go Through a Reaction or Process Which Changes Its Mahiyah (Fatwa 07378), Darul Ifta Birmingham. Says tartaric acid is a plant item and halal in itself, and that E472e is halal only if it comes from a halal (plant) source. It does not discuss the wine-derived form.
Classification audited 3 November 2026. It has not been reviewed by a scholar. How classifications work · Suggest a correction
Frequently asked questions
Is E337 halal?
E337 (Sodium potassium tartrate) is doubtful (mushbooh). Made from tartaric acid, which is often recovered from winemaking by-products (see E334). The source is rarely stated. Doubtful unless the source is stated or the product has a halal logo.
What is E337 made from?
Made from tartaric acid, often from wine sediment.
What is E337 used for?
E337 is used as an acidity regulator, typically in soft drinks, sweets, jams, sauces and processed foods.
What should I do if a product contains E337?
Look for a halal logo, a "vegan" label, or a stated plant source on the pack. If none of these are present, you can contact the manufacturer and ask for the source.
Is E337 vegetarian or vegan?
Not always. E337 (Sodium potassium tartrate) can be made from plant or animal sources, and labels rarely say which. A vegetarian or vegan label on the pack confirms a plant or synthetic source.