What is E263?

Complete guide to understanding E263 (Calcium Acetate) in your food

The Quick Answer

E263 is calcium acetate, the calcium salt of acetic acid (vinegar)—a compound that provides both pH buffering and calcium supplementation.

It’s used in food primarily as an acidity regulator, preservative, firming agent, and stabilizer—preventing microbial growth, maintaining texture in canned foods, and providing bioavailable calcium.

E263 is one of the safest and most “natural” additives available: it’s the salt form of vinegar (acetic acid), occurs naturally in many fermented foods, and provides actual nutritional calcium (approximately 25% by weight), making it both functional and nutritious.

What Exactly Is It?

E263 is calcium acetate, the calcium salt of acetic acid (also called calcium ethanoate or acetate of lime).

Acetic acid is the active ingredient in vinegar, and when acetic acid reacts with calcium, calcium acetate is formed—a white crystalline compound that combines the properties of vinegar’s antimicrobial nature with calcium’s nutritional value.

This is fundamentally different from other calcium additives: instead of providing calcium without nutritional equivalence, E263 provides actual bioavailable calcium (approximately 25% by weight) that the body can absorb and utilize, making it both a functional preservative and a nutritional supplement.

Chemical composition:

• Molecular formula: Ca(CH₃COO)₂ or C₄H₆CaO₄
• IUPAC name: Calcium diacetate
• Common forms: Anhydrous (Ca(CH₃COO)₂) and monohydrate (Ca(CH₃COO)₂•H₂O)
• CAS Number: 62-54-4 (anhydrous)
• EC Number: 200-540-9
• Molecular weight: 158.17 g/mol (anhydrous), 176.18 g/mol (monohydrate)
• Melting point: 160°C (anhydrous)

How it’s made:

Calcium acetate is produced through straightforward chemical reactions between acetic acid and calcium compounds:

• Method 1: 2CH₃COOH + Ca(OH)₂ → Ca(CH₃COO)₂ + 2H₂O (acetic acid reacted with calcium hydroxide)
• Method 2: 2CH₃COOH + CaCO₃ → Ca(CH₃COO)₂ + H₂O + CO₂ (acetic acid reacted with calcium carbonate)
• Method 3: 2CH₃COOH + CaO → Ca(CH₃COO)₂ + H₂O (acetic acid reacted with calcium oxide in exothermic reaction)

Where You’ll Find It

E263 appears in a wide range of food products:

• Bakery products and bread (preservative against mold and rope; 0.2-0.5% of flour weight)
• Canned and bottled fruits and vegetables
• Cheese and processed cheese (max 0.02% in cheese)
• Prepacked meat and processed meat products
• Packet desserts, puddings, and pie fillings
• Gelatins, puddings, and fillings (max 0.2%)
• Sweet sauces, toppings, and syrups (max 0.15%)
• Processed cereal-based foods
• Baby foods (for pH adjustment)
• Sauces and condiments
• Beverages (carbonated and non-carbonated)
• Candy and confectionery
• Dried foods and powders
• Pet foods (as calcium supplement)

Regulatory use levels:

• FDA: Approved for specific food categories with maximum levels (0.2% in baked goods, 0.02% in cheese)
• EFSA: Approved for many food categories with “not limited” use in most applications

E263 is one of the widely used food additives, though it often appears on labels simply as “acidity regulator,” “preservative,” or “firming agent” without prominence.

Why Do Food Companies Use It?

E263’s primary function is preventing microbial growth while providing calcium supplementation and pH buffering.

Food manufacturers use calcium acetate for multiple strategic advantages:

• Acidity regulation: Controls and buffers pH in food products (pH range 6.0-9.0)
• Preservation: Antimicrobial properties inhibit growth of bacteria and molds
• Rope prevention (bakery): Prevents “rope” (bacterial spoilage condition that makes bread stringy) in bread
• Mold inhibition: Inhibits mold growth in bakery products; extends shelf life
• Firming agent: Maintains firmness and texture in canned fruits and vegetables
• Calcium fortification: Provides bioavailable calcium for nutritional supplementation
• Stabilizer: Prevents separation and maintains product consistency
• Sequestrant: Binds metal ions that cause turbidity or off-flavors
• Buffering capacity: Strong buffering due to acetate’s properties
• Metal chelation: Prevents metal-ion-catalyzed spoilage
• Flavor stability: Prevents off-flavors from oxidation or metal contamination
• Thermal stability: Remains stable at processing temperatures
• Water solubility: Freely soluble; easy to incorporate into products
• Cost efficiency: Inexpensive; effective at low concentrations
• Natural image: Vinegar-based—appeals to “clean label” consumers
• Nutritional benefit: Actually provides calcium nutrition, not just functional benefit

Unique advantage in bakery: E263 is nearly irreplaceable in bread production for preventing rope—a serious bacterial spoilage condition. At concentrations of 0.2-0.5% of flour weight, it effectively inhibits the bacteria that cause this problem.

Is It Safe?

E263 is one of the safest and most comprehensively approved food additives.

Regulatory approval:

• FDA approved: Generally Recognized As Safe (GRAS) for use as firming agent, pH control agent, sequestrant, stabilizer, thickener, and texturizer
• EFSA approved: Listed in EU regulations as authorized food additive; approved for numerous food categories
• JECFA approved: ADI “not limited” (set 1973); no safety concerns identified
• Food Standards Australia New Zealand: Approved
• International approval: Approved by virtually all regulatory bodies worldwide

Safety profile:

• ADI status: “Not limited” by JECFA (1973)—indicating exceptional safety
• Natural occurrence: Found naturally in acidic fruits and fermented foods
• Acetate metabolism: Acetates are normal components of human diet; fully metabolized
• Calcium source: Provides bioavailable calcium (~25% by weight); body treats as normal nutrient
• No documented toxicity: No documented toxicity 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: Long history of safe use in food and pharmaceutical applications
• Pharmaceutical safety: Also used medically as phosphate binder in kidney disease
• No bioaccumulation: Does not accumulate in tissues; metabolized and excreted
• Low absorption risk: Acetate and calcium absorbed through normal dietary pathways

Important regulatory note: EFSA considers acetates “normal components of the diet of humans and are fully metabolized,” reflecting the exceptional status of this additive.

Natural vs Synthetic Version

E263 is synthetically manufactured but derived from natural compounds:

Source and production:

• Acetic acid source: From vinegar fermentation (natural) or synthetic acetic acid
• Calcium source: From limestone, chalk, or other mineral sources (natural)
• Reaction: Chemical synthesis combining acetic acid with calcium compounds
• Final product: Chemically identical regardless of source

Perceived “naturalness”: E263 is one of the more “natural” additives because it’s derived from vinegar (acetic acid) and calcium (mineral)—both ancient, well-known substances. While synthesized, it represents combining two “natural” components.

Vegetarian/vegan/dietary status:

• Vegan: Yes—no animal products; derived from plant fermentation (vinegar) and minerals
• Vegetarian: Yes
• Kosher: Yes (pareve)
• Halal: Yes (when vinegar source is compliant)
• Gluten-free: Yes
• Dairy-free: Yes (despite providing calcium, it’s mineral-derived, not from dairy)

Natural Alternatives

Want to avoid E263 or looking for alternative pH buffers and preservatives?

Some alternatives include:

• E260 (Acetic acid) – Parent compound; vinegar; stronger acidifying effect
• E262 (Sodium acetates) – Sodium salt of acetic acid; similar function; provides sodium instead of calcium
• E330 (Citric acid) – Alternative acidifier; different flavor profile
• E270 (Lactic acid) – Occurs in fermented foods
• E296 (Malic acid) – Apple acid; natural alternative
• E331-E333 (Sodium/potassium/calcium citrates) – Citrate-based alternatives
• E334-E337 (Tartrates) – Naturally occurring acid salts
• Vinegar – For some applications; acidifying and preservative properties
• Salt or vinegar pickling – Traditional preservation methods
• Natural fermentation: Traditional souring methods without additives

Comparison to Related Acetate Additives

E263 differs from other acetate additives:

• E260 (Acetic acid): The acidic parent compound; pure vinegar component; stronger acidification
• E262 (Sodium acetates): Sodium salts of acetic acid; similar preservation function; provides sodium instead of calcium
• E263 (Calcium acetate): Calcium salt of acetic acid; provides calcium nutrition; pH buffering
• Key distinction: E263 is unique among acetates for providing bioavailable calcium (essential nutrient) in addition to preservation

The Bottom Line

E263 (calcium acetate) is a naturally derived salt combining acetic acid (vinegar) and calcium, used as an acidity regulator, preservative, firming agent, and calcium supplement.

It’s found in bakery products (where it prevents mold and rope), canned fruits and vegetables, cheese, processed meat, and dessert mixes—where it prevents microbial growth, maintains texture, and provides calcium.

E263 is approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide with ADI “not limited,” indicating exceptional safety confidence.

Key advantages: E263 is one of the safest additives because it’s derived from vinegar (used for centuries) and provides actual bioavailable calcium (essential nutrient). It’s not just functional—it has nutritional value. Acetates are normal diet components fully metabolized by the body.

For consumers: E263 is an excellent choice. It’s safe, provides genuine nutritional benefit (calcium), and is derived from familiar, ancient substances (vinegar and minerals).

Unique nutritional advantage: Unlike most food additives that purely improve food quality/safety, E263 also fortifies food with bioavailable calcium (~25% by weight), making it both functional and nutritious.

Primary applications: E263 is particularly valuable in bakery (rope prevention), canned foods (firming), and as a calcium fortification agent in various products. Its “not limited” ADI reflects safety authorities’ confidence in this well-established additive.