E515 - Potassium sulphates
Synonyms: E515Potassium sulphatesPotassium sulfatespotassium sulfate
Contains: E515I - Potassium sulphateE515II - Potassium hydrogen sulphate
Function:
acidity regulator
Products: Found in 37 products
Potassium sulphates (E515) are simple mineral salts that combine potassium with sulfate. They help control acidity and mineral balance in some processed foods and drinks and are used far less often than many other salts. Most people will rarely see E515 on a label.
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At a glance
- What it is: Two related potassium salts of sulfuric acid
- E-number: E515 covers potassium sulfate and potassium hydrogen sulfate
- What it does: Helps regulate acidity (pH) and mineral balance in foods
- How common: Infrequent compared with other sulphates
- Diet: Suitable for vegetarians and vegans; contains no gluten or animal products
Why is Potassium sulphates added to food?
Food makers use potassium sulphates mainly as acidity regulators. Acidity regulators are additives that control pH (a measure of how acidic or basic something is), which can steady flavor, texture, and shelf life. The Codex Alimentarius, a global food standards program run by the Food and Agriculture Organization and the World Health Organization (FAO/WHO), lists potassium sulphates (INS 515) as acidity regulators and allows their use in many foods subject to good manufacturing practice.1
What foods contain Potassium sulphates?
You will not see E515 often on supermarket labels. When used, it is typically in small amounts in beverages and certain processed foods to fine-tune acidity or mineral balance. Actual uses vary by country and manufacturer, and some regions favor other acidity regulators instead.2
What can replace Potassium sulphates?
Depending on the recipe, food makers might choose:
- citric acid or its salts such as potassium citrates and sodium citrates for broad pH control
- phosphoric acid for tangy, cola-style acidity
- Other sulphate salts like sodium sulphates or calcium sulphate when a different mineral balance or processing effect is desired
The choice depends on taste, cost, labeling goals (for example, lower sodium), and how the additive behaves in that food.
How is Potassium sulphates made?
Potassium sulfate is produced industrially from potassium and sulfur sources. Common routes include reacting potassium chloride with sulfuric acid (often called the Mannheim process) or recovering and refining material from natural mineral deposits and brines. These processes yield fertilizer- and food-grade potassium sulfate; food-grade material is further purified to meet strict specifications.3 In the European Union, E515 includes two forms: potassium sulfate and potassium hydrogen sulfate, each with detailed identity and purity criteria in Commission Regulation (EU) No 231/2012.4
Is Potassium sulphates safe to eat?
Based on available data, the European Food Safety Authority (EFSA) concluded that sulfates used as food additives, including E515, are not a safety concern at the reported uses and use levels in foods.2 Very high intakes of sulfate from any source can cause temporary gastrointestinal upset in some people, especially if they are not used to it; this effect has been noted most clearly in studies and guidance on drinking water.5
Does Potassium sulphates have any benefits?
Potassium is an essential mineral that supports normal nerve and muscle function and helps maintain fluid balance. However, food additives like E515 are used in tiny amounts, so they are not a meaningful source of potassium for most people.6
Who should avoid Potassium sulphates?
- People who must limit potassium intake (for example, some individuals with chronic kidney disease or those taking certain medicines) should minimize extra potassium from all sources, including additives.6
- Individuals who are sensitive to large sulfate loads may prefer to avoid multiple sulfate-containing products at one time, especially if they have had stomach upset from high-sulfate water; if concerned, speak with a healthcare professional.2
Myths & facts
- Myth: “All sulphate additives are preservatives.” Fact: Potassium sulphates are used mainly to regulate acidity, not to preserve food.
- Myth: “E515 is the same as sulphites.” Fact: Sulphates (like E515) and sulphites (like sulphur dioxide) are different chemical groups and behave differently in food.
- Myth: “E-numbers mean artificial chemicals.” Fact: E-numbers simply indicate that the additive passed safety reviews in the European Union; many are minerals or plant-derived.
Potassium sulphates in branded foods
E515 is uncommon on retail labels. When present, it may appear as “potassium sulfate,” “potassium hydrogen sulfate,” or “E515.” It can show up in some drinks and processed foods where a small pH adjustment or mineral balance is needed. Similar roles are often filled by other additives, which is why you will more often see citric acid or phosphoric acid instead.
References
Footnotes
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General Standard for Food Additives (GSFA) – INS 515 Potassium sulfates. Codex Alimentarius (FAO/WHO). https://www.fao.org/gsfaonline/additives/details.html?id=194 ↩
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Re-evaluation of sulphates (E 514, E 515, E 516, E 517) as food additives. EFSA Journal. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2018.5482 ↩ ↩2 ↩3
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Potash (Potassium) — Mineral Commodity Summary. U.S. Geological Survey. https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-potash.pdf ↩
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Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 (entries for E 515). EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩
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Sulfate in Drinking Water — Consumer Facts. U.S. Environmental Protection Agency. https://nepis.epa.gov/Exe/ZyPDF.cgi/30006GSG.PDF?Dockey=30006GSG.PDF ↩
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Potassium — Fact Sheet for Health Professionals. National Institutes of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/ ↩ ↩2
Popular Questions
How much potassium is in glucosamine sulfate potassium chloride?
In the common “glucosamine sulfate 2KCl” form, potassium is about 13% by weight—so 1500 mg of the salt provides roughly 190–200 mg of potassium; check your product’s label for the exact amount.
How to use potassium sulfate fertilizer?
Apply according to a soil test, as potassium sulfate supplies about 50% K2O and 17–18% sulfur; it can be broadcast and incorporated, side‑dressed, or fertigated and is preferred where chloride must be limited. Always follow local agronomic guidance and the product label to avoid overapplication.
Is potassium sulfate soluble?
Yes—potassium sulfate is moderately soluble in water (about 11 g per 100 g water at 25°C), with solubility increasing at higher temperatures; it is essentially insoluble in ethanol.
What is aluminum potassium sulfate?
Aluminum potassium sulfate (potassium alum, KAl(SO4)2·12H2O) is a double sulfate salt used as a firming agent, mordant, and astringent; as a food additive it is listed separately from potassium sulfate (E522 vs. E515).
What is potassium aluminum sulfate?
Potassium aluminum sulfate—potassium alum, KAl(SO4)2·12H2O—is the same compound as aluminum potassium sulfate, a double salt used as a firming agent and pickling “alum,” distinct from potassium sulfate (E515).
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