E515II - Potassium hydrogen sulphate

At a glance

• What it is: An acid salt with the formula KHSO4, also called potassium bisulphate.
• What it does: Works mainly as an acidity regulator and acidulant to fine-tune pH.
• Taste and texture: Adds tartness and can help stabilize color, flavor, and gelling.
• Where it shows up: Used in selected processed foods and beverages that need pH control.
• Label names: “E515,” “E515ii,” “potassium hydrogen sulphate,” or “potassium bisulphate.”
• Safety: Approved in the EU; sulfates have low toxicity when used as intended.

Why is Potassium hydrogen sulphate added to food?

Food makers use potassium hydrogen sulphate to control acidity (pH). Small pH changes can make big differences in flavor, color, protein behavior, gelling, and how well a product keeps. In short, it helps recipes taste right and stay stable across shelf life. The additive is specified in EU law with identity and purity criteria for food use.¹

What foods contain Potassium hydrogen sulphate?

You may find E515II in foods and drinks that benefit from precise pH control, such as certain beverages, sugar-based products, and specialty formulations. It is less common than well-known acids like citric acid, so it may appear mainly in more technical ingredient lists. On labels in the EU, it can be listed by name or by its number as E515 or E515ii.²

What can replace Potassium hydrogen sulphate?

Depending on the recipe and target pH, food technologists may swap in:

• Citric acid for a bright, citrus-like sourness
• Malic acid for a smoother, lingering tartness
• Lactic acid for mild acidity in dairy or fermented profiles
• Phosphoric acid in colas and some beverages
• Buffer systems like sodium citrates or potassium citrates when stable pH is crucial

The best substitute depends on taste, pH target, and interactions with other ingredients.

How is Potassium hydrogen sulphate made?

Food-grade potassium hydrogen sulphate is produced by reacting a potassium base with sulfuric acid, then purifying and crystallizing the salt. One route uses sulphuric acid and a potassium alkali such as potassium hydroxide. The final product must meet strict identity and purity limits set out in EU specifications for food additives.¹

Is Potassium hydrogen sulphate safe to eat?

Within approved uses and levels, E515II is permitted in the European Union under the food additives framework, which requires a safety evaluation before listing.² Sulfate salts in general have low toxicity; the main concern at very high intakes is gastrointestinal upset (for example, diarrhea), a response also noted for sulfate in drinking water, especially in people not used to it.³ These effects occur at levels far above those used to adjust pH in foods.

Does Potassium hydrogen sulphate have any benefits?

For consumers, the benefit is indirect. By helping set and hold the right pH, E515II can:

• Support flavor balance and tartness
• Improve texture or gel strength in some recipes
• Help preserve color and reduce off-notes
• Aid shelf stability by creating less favorable conditions for spoilage organisms

These effects come from pH control rather than from nutritional value.

Who should avoid Potassium hydrogen sulphate?

• People on potassium-restricted diets (for example, some people with kidney disease) should monitor potassium from all sources and follow medical advice.⁴
• Infants and people with sensitive digestion may be more prone to temporary diarrhea from high sulfate exposure; this is documented for water and reflects sulfate’s osmotic effects at elevated levels.³

If you have a specific medical condition, ask a healthcare professional about your diet.

Myths & facts

• Myth: “Sulfates are the same as sulfites.” Fact: They are different chemical groups. Sulfites (used as preservatives) can trigger sensitivity in some people, while sulfates like E515II are a separate class.
• Myth: “Bisulphate always makes food taste harsh.” Fact: At the small amounts used, it fine-tunes pH. Final taste depends on the whole recipe.
• Myth: “It’s only an industrial chemical.” Fact: Food-grade E515II must meet strict purity standards before use in foods.¹

Potassium hydrogen sulphate in branded foods

This additive is not among the most common acids on supermarket labels, so you may see it mainly in specialized or technical formulations. Look for “potassium hydrogen sulphate,” “potassium bisulphate,” “E515,” or “E515ii” in the ingredients list. If you are tracking potassium or acidity, contact the manufacturer for product-specific details.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³

2. Regulation (EC) No 1333/2008 on food additives — EU authorisation framework. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩ ↩²

3. Toxicological Profile for Sulfates, Sulfites, Thiosulfates, and Sulfur Dioxide — ATSDR/CDC. https://www.atsdr.cdc.gov/toxprofiles/tp116.pdf ↩ ↩²

4. Potassium in diet — MedlinePlus/NIH. https://medlineplus.gov/ency/article/002413.htm ↩