E507 - Hydrochloric acid

At a glance

• What it is: A water solution of hydrogen chloride, used as an acidity regulator and processing aid.
• Why it’s used: To control pH, support reactions like protein hydrolysis, and keep formulas consistent.
• Where it shows up: Mostly in processing (for example, making hydrolyzed plant protein); often not listed on labels because it no longer has a function in the finished food.
• Regulations: Authorized in the EU as E507 and permitted in the U.S. when used under good manufacturing practice.

Why is Hydrochloric acid added to food?

Food makers use hydrochloric acid to quickly and precisely lower pH. In legal terms, it is an “acidity regulator,” a class of additives the European Union (EU) allows to be used at levels needed to achieve the intended effect (a principle called quantum satis, or “as much as needed”).¹² It is also used as a processing aid, such as during acid hydrolysis of plant proteins to make flavoring ingredients, after which the acid is neutralized or removed.³

What foods contain Hydrochloric acid?

You are most likely to encounter hydrochloric acid during processing steps, not as a functional ingredient in the finished product. In the U.S., substances used only as processing aids and present at insignificant levels with no technical effect in the final food are exempt from label declaration, which is why you may not see “hydrochloric acid” on the ingredient list even if it was used upstream.⁴ In the EU, it is listed as E507 when it remains a functional additive in the final food.¹

What can replace Hydrochloric acid?

Several other acids can adjust pH or provide tartness, depending on the recipe:

• Citric acid for fruit-forward tartness
• Acetic acid (vinegar) for sharper sour notes
• Lactic acid for mild, dairy-like acidity
• Phosphoric acid for a clean “cola-style” bite
• Glucono delta-lactone for slow, gentle acidification

When raising pH instead of lowering it, manufacturers might use alkalis such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, or buffering agents like sodium bicarbonate.

How is Hydrochloric acid made?

Hydrochloric acid is simply hydrogen chloride gas dissolved in water. Commercially, it is produced and sold as aqueous solutions at various strengths for industrial and food uses.⁵ Food-grade hydrochloric acid must meet purity and identity specifications defined by EU law when used as E507.¹

Is Hydrochloric acid safe to eat?

In the EU, E507 is an authorized food additive with official purity specifications and may be used in line with Regulation (EC) No 1333/2008 for acidity regulators.¹² In the United States, hydrochloric acid appears on the Food Additive Status List as Generally Recognized as Safe (GRAS) when used in accordance with good manufacturing practice (GMP), reflecting its long history of technical use in foods.³ Because it is a strong acid, it is handled in controlled conditions; in finished foods, it is used at low levels or as a processing aid and is often neutralized before sale.⁴

Does Hydrochloric acid have any benefits?

For manufacturers, controlled acidification helps:

• Set or stabilize texture by managing pH-sensitive ingredients (for example, gelling systems).
• Keep flavor profiles consistent from batch to batch.
• Enable specific processing steps, like acid hydrolysis, that create desired flavors.

For consumers, the “benefit” is indirect: consistent taste, texture, and quality in foods that were made with careful pH control.

Who should avoid Hydrochloric acid?

• People who find highly acidic foods uncomfortable (for example, some with reflux) may wish to limit very sour foods in general. This is about overall acidity, not hydrochloric acid specifically.
• As a raw chemical, hydrochloric acid is corrosive and must be handled by trained staff; this does not apply to the tiny, neutralized, or diluted amounts relevant to finished foods.

If you have a medical condition that requires a low-acid diet, follow your clinician’s advice and review products’ overall acidity.

Myths & facts

• Myth: “Hydrochloric acid is the same as bleach.” Fact: It is a different chemical from chlorine bleach; do not confuse hydrochloric acid with chlorine or hypochlorite solutions.
• Myth: “If it’s used, it must be in my food.” Fact: When used only as a processing aid and not functioning in the final food, it may be neutralized or removed and does not have to appear on the label in the U.S.⁴
• Myth: “It always makes foods taste very sour.” Fact: Food technologists dose acids precisely; many uses are for pH control during production, not to make foods taste sour.

Hydrochloric acid in branded foods

On labels, you may see “hydrochloric acid” or “E507” if it remains as an acidity regulator in the finished product (more common in the EU). In many cases, it is used only during processing and then neutralized or washed out; in the U.S. such processing aids are exempt from declaration on the ingredient list.⁴ If you are checking a specific brand, look for E-numbers on EU labels or contact the manufacturer’s customer service for processing information.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³ ↩⁴

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

3. Food Additive Status List (Hydrochloric acid, GRAS) — U.S. FDA. https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩ ↩²

4. 21 CFR 101.100(a)(3): Exemptions from food labeling; incidental additives and processing aids — eCFR. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/section-101.100 ↩ ↩² ↩³ ↩⁴

5. Hydrochloric Acid (Hydrogen Chloride) compound summary — NIH PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/Hydrochloric-acid ↩