E501II - Potassium hydrogen carbonate

At a glance

• E-number: E501ii (the potassium bicarbonate form of potassium carbonates)
• What it does: Leavening agent and acidity regulator; helps dough rise and controls pH
• Common in: Low‑sodium baking powder, cakes, cookies, crackers, waffles, and effervescent drink or vitamin tablets
• Also called: Potassium hydrogen carbonate, potassium bicarbonate
• Diet notes: Mineral-based; suitable for vegan, vegetarian, and gluten‑free diets
• Taste/texture: Neutral taste; helps create a light, open crumb in baked goods

Why is Potassium hydrogen carbonate added to food?

Food makers use it mainly to create lift. When potassium bicarbonate meets an acid, it releases carbon dioxide gas, which forms bubbles that make cakes, cookies, and other baked goods rise. It also works as a mild acidity regulator, helping keep mixtures stable and at the right pH.

What foods contain Potassium hydrogen carbonate?

You are most likely to find it in:

• Low‑sodium baking powders and baking mixes
• Cookies, crackers, quick breads, waffles, and pancakes
• Cocoa or chocolate drink mixes
• Effervescent tablets (for drinks or supplements)
• Some ready‑to‑bake doughs and biscuit doughs

On EU labels it appears as “E501ii” or “potassium hydrogen carbonate;” on other labels, as “potassium bicarbonate.”

What can replace Potassium hydrogen carbonate?

Swap choices depend on why you’re using it:

• For leavening with standard sodium levels: use sodium bicarbonate (baking soda).
• For sodium‑free or low‑sodium lift: pair potassium bicarbonate substitutes with an acid such as citric acid or glucono‑delta‑lactone; or use a balanced baking powder that relies on acid salts like monocalcium phosphate.
• For certain crisp cookies or crackers: ammonium hydrogen carbonate can give strong lift without leaving sodium, but it’s best in thin, dry bakes.

Note: If you change leavening systems, you may need to adjust acid levels and liquid to keep the recipe balanced.

How is Potassium hydrogen carbonate made?

Industrially, potassium bicarbonate is commonly produced by directing carbon dioxide into an aqueous solution of potassium carbonate. This “carbonation” step converts part of the carbonate into the hydrogen carbonate (bicarbonate) form, which is then filtered, dried, and milled to a fine powder.¹

Is Potassium hydrogen carbonate safe to eat?

In the European Union, E 501 covers potassium carbonate (i) and potassium hydrogen carbonate (ii); both forms are authorized food additives with identity and purity criteria set in Commission Regulation (EU) No 231/2012.² The European Food Safety Authority (EFSA) re‑evaluated potassium carbonates (E 501) and concluded there is no safety concern for their reported uses and use levels in food.¹ EFSA did not consider a numerical ADI (acceptable daily intake) necessary, based on their toxicological profile and exposure estimates.¹

Does Potassium hydrogen carbonate have any benefits?

• Helps reduce sodium: It can replace some or all of the sodium bicarbonate in recipes and mixes, cutting sodium content while still providing lift.
• Neutral taste and gentle action: It is less likely to add a salty taste and works well with mild acids in delicate batters.
• Contributes potassium: It adds a small amount of dietary potassium, though typical serving sizes are too low to rely on for nutrition.

Who should avoid Potassium hydrogen carbonate?

People who must limit potassium should be cautious. This includes many with chronic kidney disease and some who take medicines that raise blood potassium (for example, ACE inhibitors, ARBs, or potassium‑sparing diuretics). Even though food uses typically add small amounts, total dietary potassium still matters for these groups.³ If you have a kidney condition or a history of hyperkalemia (high blood potassium), ask a healthcare professional about potassium in your diet.⁴

EFSA is the European Food Safety Authority; ADI means acceptable daily intake; NIH is the U.S. National Institutes of Health; and NIDDK is NIH’s National Institute of Diabetes and Digestive and Kidney Diseases.

Myths & facts

• Myth: It’s the same as baking soda. Fact: Baking soda is sodium bicarbonate; potassium bicarbonate performs similarly but adds potassium and no sodium.
• Myth: It always makes food taste bitter. Fact: Used at normal levels and paired with the right acid, it has a neutral taste.
• Myth: It is only for industrial baking. Fact: It appears in retail low‑sodium baking powders and home baking recipes, too.

Potassium hydrogen carbonate in branded foods

You’ll often see it on ingredient lists for low‑sodium baking powders, some ready‑to‑bake doughs, effervescent vitamin tablets, and powdered drink mixes. Product labels may list it as “potassium bicarbonate,” “potassium hydrogen carbonate,” or “E501ii” depending on the market.

References

Footnotes

1. Re‑evaluation of potassium carbonates (E 501) and sodium carbonates (E 500) as food additives — EFSA Journal. https://www.efsa.europa.eu/en/efsajournal/pub/5755 ↩ ↩² ↩³

2. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 (entry for E 501 Potassium carbonates). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩

3. Potassium — Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/ ↩

4. Hyperkalemia (High Blood Potassium) — NIDDK, NIH. https://www.niddk.nih.gov/health-information/kidney-disease/hyperkalemia ↩