What is E261?

Complete guide to understanding E261 (Potassium Acetate) in your food

The Quick Answer

E261 is potassium acetate, the potassium salt of acetic acid (the main component of vinegar)—combines vinegar’s preservation properties with potassium’s nutritional value.

It’s used in food primarily as a preservative, acidity regulator, flavor enhancer, and dough conditioner—preventing microbial growth while providing bioavailable potassium instead of sodium.

E261 is one of the safest food additives and is particularly valuable for low-sodium products and potassium supplementation. It provides genuine nutritional benefit (potassium) alongside functional preservation, similar to how E263 (calcium acetate) provides calcium nutrition.

What Exactly Is It?

E261 is potassium acetate, the potassium salt of acetic acid—created when acetic acid (vinegar) reacts with potassium compounds.

E261 actually comprises two chemical forms: E261(i) potassium acetate (anhydrous or trihydrate) and E261(ii) potassium hydrogen diacetate (potassium diacetate)—a 1:1 mixture of potassium acetate and acetic acid, similar to how E262(ii) is a mixture for sodium diacetate.

This compound uniquely combines the preservation properties of vinegar (acetic acid) with potassium’s nutritional value—making it both functional and nutritious. The body recognizes potassium acetate as a normal nutrient source.

Chemical composition:

Additional chemical details:

• CAS Number (E261(i)): 127-08-2
• Molecular weight (E261(i) anhydrous): 98.14 g/mol
• Molecular weight (E261(ii)): ~196 g/mol
• EC Number (E261(i)): 204-822-2
• Melting point (E261(i)): 292°C (high thermal stability)

How it’s made:

Potassium acetate is produced through straightforward chemical reactions between acetic acid and potassium compounds:

• Method 1: Acetic acid + Potassium carbonate (K₂CO₃) → Potassium acetate + Water + Carbon dioxide
• Method 2: Acetic acid + Potassium hydroxide (KOH) → Potassium acetate + Water
• Method 3: Acetic acid + Potassium bicarbonate (KHCO₃) → Potassium acetate + Water + Carbon dioxide

For E261(ii) (potassium diacetate specifically): Anhydrous potassium acetate is reacted with excess glacial acetic acid to create the characteristic 1:1 mixture with available acetic acid.

Where You’ll Find It

E261 appears in a wide range of food products, particularly those requiring low-sodium formulation or potassium supplementation:

• Bread and baked goods (very common) – preservative against mold and rope; dough conditioner
• Pickles and pickled vegetables
• Canned and bottled fruits and vegetables
• Processed and cured meat products (sausages, pâté, luncheon meat)
• Cheese and processed cheese
• Condiments and seasonings (ketchup, mustard, mayonnaise)
• Sauces and gravies
• Soups and broths (packet varieties)
• Snacks and chips (particularly common in E261(ii) form for flavor)
• Instant foods and meal replacements
• Low-sodium food products (primary advantage over E262)
• Baby foods (pH adjustment)
• Dressings and vinaigrettes

Regulatory use scope: EFSA approved for use in multiple food categories since 2013. FDA approved as synthetic flavoring substance. Often used in “low-sodium” or “reduced-sodium” formulations where potassium supplementation is desired.

E261 is less commonly used than E262 (sodium acetate) in mainstream products, but is increasingly used in health-conscious, low-sodium, and potassium-enriched formulations.

Why Do Food Companies Use It?

E261’s primary function is preventing microbial growth while providing potassium supplementation and pH buffering.

Food manufacturers use potassium acetate for multiple strategic advantages:

• Preservation: Inhibits growth of bacteria, molds, and fungi; prevents spoilage
• Rope prevention (bakery): Prevents “rope”—a serious bacterial spoilage condition in bread
• Mold inhibition: Significantly inhibits mold growth in baked goods
• Antimicrobial action: Superior to many alternative preservatives against fungi
• Acidity regulation: Controls and lowers pH in food products
• pH buffering: Maintains stable pH (buffering range 3.6-5.6)
• Potassium supplementation: Provides bioavailable potassium (~39% by weight)
• Sodium-free alternative: Unlike E262, provides NO sodium; ideal for low-sodium products
• Nutritional benefit: Actually provides potassium nutrition (essential mineral)
• Flavor enhancement: Particularly E261(ii); adds tangy, salty taste
• Taste improvement: Masks unwanted flavors; enhances savory notes
• Dough conditioner (bakery): Improves dough texture, elasticity, gluten development
• Shelf life extension: Prevents microbial growth and oxidative spoilage
• Sequestrant: Binds metal ions that cause turbidity or off-flavors
• Thermal stability: Remains stable at processing temperatures
• Water solubility: Freely soluble; easy to incorporate
• Cost efficiency: Inexpensive; effective at low concentrations
• Marketing advantage: “Low-sodium,” “potassium-enriched,” “heart-healthy” claims

Unique advantage for low-sodium products: E261 is irreplaceable in low-sodium food formulations where both preservation AND potassium supplementation are desired. It serves a dual purpose: prevents spoilage AND provides nutrition.

Is It Safe?

E261 is safe and extensively approved by major regulatory authorities.

Regulatory approval:

• FDA approved: Classified as synthetic flavoring substance; approved for food use
• EFSA authorized: First authorized in 2013; listed as approved food additive in European Union
• JECFA approved: ADI “not limited” (1973) or very generous limits; no safety concerns
• Food Standards Australia New Zealand: Approved
• International approval: Approved by virtually all regulatory bodies worldwide

Safety profile:

• ADI status: “Not limited” for E261(i)—highest safety rating
• Natural origin: Derived from acetic acid (vinegar); potassium is natural mineral
• Metabolism: Body fully metabolizes potassium acetate as normal nutrients
• Potassium handling: Body has efficient potassium regulation mechanisms
• Acetate metabolism: Acetates are normal components of body cells
• No documented toxicity: No toxicity documented at food use levels
• No carcinogenicity: No evidence of cancer-causing potential
• No reproductive effects: Safe for pregnancy and breastfeeding
• No genotoxicity: No evidence of genetic damage
• Decades of safe use: Used in food industry without health incidents
• Pharmaceutical history: Potassium acetate also used in pharmaceutical applications
• No bioaccumulation: Does not accumulate in tissues
• Low absorption risk: Potassium and acetate absorbed through normal dietary pathways

Important note about potassium intake: For the general population with normal kidney function, potassium acetate is safe. However, people with certain medical conditions should be aware of potassium intake:

Natural vs Synthetic Version

E261 is synthetically manufactured but derived from natural compounds:

Source and production:

• Acetic acid source: From vinegar fermentation (natural) or synthetic acetic acid
• Potassium source: From mineral sources (potassium carbonate/hydroxide/bicarbonate)
• Reaction: Chemical synthesis combining acetic acid with potassium compounds
• Final product: Chemically identical regardless of source

Perceived “naturalness”: E261 is derived from vinegar (natural) and potassium (mineral)—both ancient, well-known substances. While synthesized, it’s relatively “natural-origin” compared to fully synthetic additives.

Vegetarian/vegan/dietary status:

• Vegan: Yes—no animal products; derived from plant fermentation (vinegar) and minerals
• Vegetarian: Yes
• Kosher: Yes (pareve)
• Halal: Yes
• Gluten-free: Yes
• Dairy-free: Yes

Natural Alternatives

Want to avoid E261 or looking for alternative preservatives and potassium sources?

Some alternatives include:

• E260 (Acetic acid/vinegar) – Parent compound; stronger sour flavor; no potassium
• E262 (Sodium acetate) – Sodium salt instead; provides sodium, not potassium
• E263 (Calcium acetate) – Calcium salt; provides calcium instead of potassium
• E270 (Lactic acid) – Occurs in fermented foods; no potassium
• E296 (Malic acid) – Apple acid; naturally occurring
• E330 (Citric acid) – Common acidifier; no potassium
• E334-E337 (Tartrates) – Naturally occurring acid salts
• Potassium chloride – Direct potassium supplement (different properties)
• Potassium citrate – Alternative potassium salt
• Vinegar – For some applications; stronger flavor
• Natural fermentation: Traditional souring without additives

E261(i) vs E261(ii) Comparison

Comparison to Related Acetates

E261 differs from other acetate additives:

• E260 (Acetic acid): Pure vinegar component; stronger acidification; no potassium
• E262 (Sodium acetate): Sodium salt instead of potassium; similar preservation; provides sodium (not ideal for low-sodium products)
• E263 (Calcium acetate): Calcium salt; provides calcium (~25% by weight) instead of potassium
• Key distinction: E261 unique for combining preservation with potassium supplementation; ideal for low-sodium, high-potassium formulations

The Bottom Line

E261 (potassium acetate) is a preservative, acidity regulator, and potassium supplement derived from acetic acid (vinegar)—used in bread, pickles, processed meat, and low-sodium food products.

It’s approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide with ADI “not limited,” indicating exceptional safety confidence.

Key advantages: E261 is exceptionally safe because it’s derived from vinegar (used safely for centuries) and provides potassium (essential nutrient). ADI “not limited” indicates no safety concerns. Particularly valuable for low-sodium products and potassium supplementation.

Unique nutritional benefit: Unlike most preservatives that are purely functional, E261 provides genuine bioavailable potassium (~39% by weight)—making it both functional AND nutritious.

For consumers: E261 is an excellent choice—safe, provides real nutritional benefit (potassium), and derived from natural compounds (vinegar). Ideal for those seeking low-sodium, potassium-enriched foods.

Primary application: E261 is invaluable in low-sodium food formulations where both preservation AND potassium supplementation are desired. It fills a unique niche that other preservatives cannot match.

Compared to E262: Both are excellent acetate preservatives. Choose E261 for low-sodium products or potassium supplementation; choose E262 if sodium contribution is acceptable or desirable.