What is E353?

Complete guide to understanding E353 (Metatartaric Acid) in your food

The Quick Answer

E353 is metatartaric acid, a polymeric lactone derived from tartaric acid (a naturally occurring acid abundant in grapes) through heat dehydration.

It’s used in food primarily as a wine stabilizer and acidity regulator—preventing the precipitation (formation of crystals) of tartrates in wine and other beverages without the need for cold treatment or harsh processing.

E353 is unique: while it’s a modified form of tartaric acid, it degrades to tartaric acid in the human body, making it biochemically equivalent to a natural compound. It’s one of the most specialized and wine-specific food additives available.

What Exactly Is It?

E353 is metatartaric acid, a polymeric lactone of variable composition and molecular weight created by heating tartaric acid to approximately 170°C.

Unlike tartaric acid (E334) which is a simple organic acid, metatartaric acid is a polymerized form—meaning the acid molecules have bonded together during the heating process to create larger, polymer chains of variable length and composition. This gives it fundamentally different chemical properties.

The critical distinction is that metatartaric acid precipitates (prevents crystal formation) without requiring the extreme cooling that regular tartaric acid treatment needs. However, metatartaric acid is not stable at high temperatures—it gradually hydrolyzes (breaks apart) back into tartaric acid, which is why it must be used in cold-bottled products.

Chemical characteristics:

• Basic structure: Polymeric lactone of variable composition
• Parent compound: Tartaric acid (L-tartaric acid, naturally occurring)
• Production temperature: Approximately 170°C (dry heating)
• Molecular composition: Variable molecular weight (polymers of different chain lengths)
• CAS Number: 6988-21-2
• Variable nature: Not a single defined chemical but a mixture of polymers of different weights

How it’s made:

Metatartaric acid is produced through a simple but precise thermal process:

• Step 1: Tartaric acid (extracted from wine fermentation byproducts or synthesized) is placed in heating equipment
• Step 2: The tartaric acid is heated to approximately 170°C under controlled conditions
• Step 3: At this temperature, the acid molecules undergo dehydration and polymerization—water molecules are removed and the acid chains bond together
• Step 4: The resulting polymeric product is cooled and ground into fine powder
• Step 5: The powder is used directly as food additive

Key biochemical point: When metatartaric acid enters the digestive system, it hydrolyzes (breaks down) into tartaric acid. The EFSA assumes complete hydrolysis before systemic absorption, meaning the body treats it as tartaric acid for safety assessment purposes.

Where You’ll Find It

E353 appears in limited but specialized food applications:

• Wine (dominant use) – prevents tartrate precipitation during storage and transport
• Fruit juices (particularly grape juice)
• Cider and other fermented beverages
• Fruit juice-based drinks
• Some specialty beverages requiring tartrate stabilization without cold treatment
• Limited use in other foods compared to its wine application

Regulatory use restriction: E353 is particularly authorized and recommended for use in wine under Regulation (EC) No 934/2019 and is described as a “stabilising agent” specifically for wine production.

E353 is one of the most specialized food additives—its use is essentially limited to wine and similar fermented beverages where tartrate precipitation prevention is critical. It’s rarely found in general consumer food products.

Why Do Food Companies (Particularly Winemakers) Use It?

E353’s primary function is preventing tartrate crystal precipitation in wine without requiring extreme cooling.

Winemakers use metatartaric acid for critical advantages:

• Tartrate stabilization: Prevents crystalline precipitation of potassium bitartrate (cream of tartar) and calcium tartrate during storage
• Crystal prevention: Stops unwanted “wine diamonds” (tartrate crystals) from forming in bottles
• Room temperature effectiveness: Works at normal storage temperatures without requiring expensive cold-stabilization treatment
• Cost savings: Eliminates need for expensive cold-stabilization equipment for many wines
• Clarity maintenance: Keeps wine clear and visually appealing; prevents appearance of crystals that concern consumers
• Shelf life extension: Prevents crystal formation during prolonged storage and transport
• Selective application: Allows winemakers to treat some lots without others
• Wine quality preservation: Doesn’t require harsh treatments that might affect flavor
• Alternative to cold treatment: Room-temperature alternative to refrigeration (cost and energy reduction)
• Rapid effect: Works quickly (within days) unlike extended cold stabilization
• Environmental benefit: Reduces energy consumption compared to cold-stabilization systems
• Acidity regulation: Also provides pH control as secondary benefit
• Metal chelation: Can bind metal ions that cause turbidity
• International acceptance: Permitted in major wine-producing countries

Unique advantage in winemaking: E353 is nearly irreplaceable in winemaking because it prevents tartrate crystal formation without the extreme cooling that traditional tartrate stabilization requires. This makes it economically and operationally superior to cold stabilization for many wine producers.

Is It Safe?

E353 is approved by major regulatory authorities and is considered safe for food use.

Regulatory approval:

• FDA approved: Generally used with no official safety objections
• EFSA approved: Listed in EU Regulation 934/2019 as authorised for wine production
• JECFA approved: Group ADI 240 mg/kg body weight per day (set 2020, expressed as tartaric acid)
• 2020 EFSA Re-evaluation: Most recent comprehensive assessment confirmed safety
• International approval: Approved in virtually all major wine-producing countries

2020 EFSA Re-evaluation findings:

The Panel on Food Additives and Flavourings (EFSA) concluded:

• Assumption of complete hydrolysis: Metatartaric acid is fully hydrolyzed pre-systemically to L-(+)-tartaric acid
• Equivalent to tartaric acid: For safety assessment, treated as equivalent to tartaric acid (E334)
• Group ADI established: Included in group ADI of 240 mg/kg body weight per day with other tartrates (E334-E337, E354)
• No safety concern: Concluded “no safety concern for the use of metatartaric acid (E 353) at the reported use and use level”
• Genotoxicity: No indication of genetic damage
• Reproductive/developmental effects: No evidence of adverse reproductive effects
• Carcinogenicity: No evidence of cancer-causing potential

Safety profile:

• Natural precursor: Derived from tartaric acid, a natural compound in grapes
• Metabolic fate: Hydrolyzed to tartaric acid—a normal dietary compound
• Tartaric acid history: Consumed safely in wine and fruits for centuries
• Wine exposure: Anyone consuming wine is exposed to both tartaric acid and residual tartrate stability agents
• Centuries of safe use: Long history in wine production without documented health incidents
• Low exposure levels: Used at concentrations typically <200 mg/L in wine (very low exposure)
• No documented adverse effects: No widespread adverse effects from wine use documented
• Temperature-dependent degradation: Stability depends on storage temperature; degrades at high temperatures

Natural vs Synthetic Version

E353 is derived from natural tartaric acid but synthetically modified:

Source and production:

• Starting material: Tartaric acid from wine fermentation byproducts or synthesized tartaric acid
• Processing method: Heat treatment (thermal polymerization via dehydration)
• Final product: Polymer of tartaric acid; not found in nature
• Biochemical equivalence: Degrades to tartaric acid in the body

Perceived “naturalness”: E353 is natural-origin (from tartaric acid) but synthetically modified through heat treatment. Regulatory classification is “food additive” rather than “natural,” but its derivation from natural grapes and rapid conversion to natural tartaric acid makes it relatively “natural-origin.”

Vegetarian/vegan/dietary status:

• Vegan: Yes—no animal products
• Vegetarian: Yes
• Kosher: Yes (pareve)
• Halal: Yes (when from plant sources)
• Gluten-free: Yes
• Dairy-free: Yes

Natural Alternatives

Want to avoid E353 or looking for alternative tartrate stabilizers?

Some alternatives include:

• E334 (Tartaric acid) – Parent compound; requires cold stabilization
• E335-E337 (Sodium/potassium tartrates) – Alternative tartrate salts
• E354 (Calcium tartrate) – Calcium salt; different precipitation properties
• Cold stabilization – Traditional method of cooling wine to precipitate tartrates naturally (requires expensive refrigeration equipment)
• Electrodialysis – Physical tartrate removal method (high cost)
• Mannoproteins or yeast derivatives – Natural stabilization agents
• Carbohydrate gums – Alternative stabilizers
• Simply accept crystallization: Some premium wines embrace “wine diamonds” as evidence of purity and minimal processing

Related Tartrate Additives

E353 is part of the tartrate family:

• E334 (Tartaric acid): L-(+)-tartaric acid; the natural parent acid
• E335 (Sodium tartrates): Sodium salts of tartaric acid
• E336 (Potassium tartrates): Potassium salts of tartaric acid
• E337 (Sodium potassium tartrate): Mixed sodium-potassium salt (Rochelle salt)
• E353 (Metatartaric acid): Polymerized/heat-treated tartaric acid
• E354 (Calcium tartrate): Calcium salt of tartaric acid

Key difference: E353 is the only polymeric form; other tartrates are simple salts. This polymer structure is what gives E353 its unique tartrate-precipitating properties without requiring cold treatment.

The Bottom Line

E353 (metatartaric acid) is a heat-modified form of natural tartaric acid used specifically for wine stabilization.

It’s found almost exclusively in wine and similar fermented beverages—where it prevents the formation of unwanted tartrate crystals without requiring expensive cold-stabilization treatment.

E353 is approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide, with a group ADI of 240 mg/kg body weight per day (set 2020).

Key advantages: E353 is exceptionally safe because it’s derived from tartaric acid (naturally occurring in grapes) and immediately hydrolyzes to tartaric acid in the human body. The 2020 EFSA re-evaluation confirmed safety without restrictions.

Wine industry importance: E353 is nearly irreplaceable in winemaking for preventing tartrate precipitation at room temperature without extreme cooling. This makes it economically and operationally superior to traditional cold stabilization.

For consumers: E353 is an excellent additive—highly specialized, exceptionally safe, and derived from natural grapes. Wine drinkers have been safely consuming wines treated with metatartaric acid and similar stabilizers for decades.

Specialized application: E353 is one of the most specialized food additives, with its primary application essentially limited to wine and similar fermented beverages. It’s rarely encountered outside this specialized context.