E501I - Potassium carbonate

At a glance

• E-number: E501i; name on labels: “potassium carbonate,” sometimes shown as “E501” or “potassium carbonates”
• What it does: pH control (acidity regulator), buffering agent, stabilizer; can support leavening when paired with acids
• Where it appears: alkalized (Dutch-process) cocoa, certain pasta/noodle products, and some baked goods
• Diet notes: adds potassium; generally vegan and gluten-free
• Regulatory status: allowed in the EU (E 501) and GRAS in the U.S. when used in line with good manufacturing practice

Why is Potassium carbonate added to food?

Food makers use potassium carbonate because it is alkaline and highly soluble, which makes it useful for controlling acidity (pH) and stabilizing formulations. In cocoa processing, it is a permitted “alkalizing agent” that mellows acidity and deepens color. In doughs and noodles, small amounts can adjust pH to influence texture and browning, and it can help generate carbon dioxide when paired with acidic ingredients. In both the EU and U.S., it is recognized as a basic pH control/processing aid when used as intended.¹²

What foods contain Potassium carbonate?

• Alkalized (Dutch-process) cocoa and cocoa powders, where potassium carbonate is one of the permitted alkalizing agents.³
• Some pasta and noodle products made under U.S. standards of identity, which allow alkaline salts such as potassium carbonate as optional ingredients.⁴
• Select baked goods and confectionery where an alkaline salt helps with pH, color, or texture.

Because it functions in pH control, you’ll see it most in foods where acidity and color need fine-tuning, such as cocoa-based mixes and certain noodles.

What can replace Potassium carbonate?

Choosing a substitute depends on the job you need done:

• For alkalinity/pH control: consider sodium carbonate or, for stronger alkalinity, potassium hydroxide or sodium hydroxide in carefully controlled amounts.
• For leavening with an acid: potassium hydrogen carbonate, sodium bicarbonate, or ammonium hydrogen carbonate are common options.
• For acid-base balancing from the other side: acids such as citric acid or phosphoric acid can fine-tune pH in tandem with a carbonate or bicarbonate.

Note that switching from potassium to sodium salts changes both taste and the mineral (potassium vs sodium) profile of the food.

How is Potassium carbonate made?

Commercially, potassium carbonate is typically produced by reacting potassium hydroxide with carbon dioxide to form potassium bicarbonate, then heating (calcining) it to yield potassium carbonate and release carbon dioxide. It can also be obtained by directly carbonating potassium hydroxide solution and drying the product. Historically, it was derived from “potash” made by leaching wood ash, but modern production uses more controlled chemical processes.⁵

Is Potassium carbonate safe to eat?

Yes, when used as intended in food. In the United States, the Food and Drug Administration (FDA) affirms potassium carbonate as Generally Recognized as Safe (GRAS) for direct addition to food in accordance with good manufacturing practice.² In the European Union, potassium carbonates are authorized food additives with published identity and purity specifications.¹ As with all alkaline salts, food manufacturers use it at levels appropriate for the product’s pH and taste.

Does Potassium carbonate have any benefits?

• Flavor and color control: In cocoa, alkalizing with potassium carbonate reduces sharp acidity and can create a darker, smoother-tasting cocoa powder.³
• Texture and processing: In noodle and pasta systems, permitted alkaline salts can help set protein structure and adjust dough handling, contributing to a springier bite.⁴
• Leavening support: In recipes that include an acid, carbonate/bicarbonate systems can release carbon dioxide to aerate doughs and batters.

Who should avoid Potassium carbonate?

• People on potassium-restricted diets, such as many with chronic kidney disease (CKD), may need to limit added sources of potassium, including potassium salts used in foods.⁶
• Individuals advised by a healthcare professional to control alkalizing agents or mineral salts should read ingredient lists and choose alternatives as needed.

For most healthy consumers, typical amounts from foods are not a concern when used within regulatory limits.

Myths & facts

• Myth: “Potassium carbonate is the same as baking soda.” Fact: Baking soda is sodium bicarbonate; potassium carbonate is a different salt with stronger alkalinity and no sodium.
• Myth: “Alkalized cocoa is artificial.” Fact: Alkalization is a permitted processing step that uses approved alkalizing agents like potassium carbonate to adjust flavor and color.³
• Myth: “All E-numbers are unsafe.” Fact: E-numbers are simply identifiers for approved additives in the EU, including basic mineral salts like potassium carbonates.¹
• Fact: Label wording can vary: you may see “potassium carbonate,” “E501,” or “potassium carbonates,” depending on the market.

Potassium carbonate in branded foods

You’re most likely to find potassium carbonate on labels of:

• Alkalized (Dutch-process) cocoa powders and cocoa-containing drink mixes
• Certain instant noodle or pasta products made with alkaline salts
• Some cookies, crackers, or confectionery where pH adjustment is desired

Check ingredient lists for “potassium carbonate,” “E501,” or “E501i.”

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — EU additive specifications (includes E 501 potassium carbonates). https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³

2. Potassium carbonate — 21 CFR 184.1619, GRAS status and use in food. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/subpart-B/section-184.1619 ↩ ↩²

3. Cocoa — 21 CFR 163.110; permitted alkalizing agents include potassium carbonate. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-163/section-163.110 ↩ ↩² ↩³

4. Macaroni products — 21 CFR 139.110; optional ingredients include alkaline salts. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-139/section-139.110 ↩ ↩²

5. Potassium carbonate — PubChem Compound Summary; identity and manufacturing routes. https://pubchem.ncbi.nlm.nih.gov/compound/Potassium-carbonate ↩

6. Chronic kidney disease diet and potassium — NIDDK (NIH). https://www.niddk.nih.gov/health-information/kidney-disease/ckd-diet-eating-nutrition ↩