What is E228?
Complete guide to understanding E228 (Potassium Hydrogen Sulfite) in your food
The Quick Answer
E228 is potassium hydrogen sulfite (also called potassium bisulfite), a preservative and antioxidant additive used in food.
It’s used to prevent spoilage, inhibit bacterial and fungal growth, maintain color and flavor, and extend shelf life.
Most people consume it regularly if they drink wine or beer, eat dried fruit, or consume fruit juices.
📌 Quick Facts
- Category: Preservative and Antioxidant
- Found in: Wine, beer, dried fruits, fruit juices, canned vegetables, baked goods
- Safety: Approved by major regulatory agencies with usage restrictions
- Approved by: FDA (USA), EFSA (Europe), UK Food Standards Authority, and most major regulatory bodies
What Exactly Is It?
E228 is potassium hydrogen sulfite, also known as potassium bisulfite. It has the chemical formula KHSO₃.
E228 is technically not a single pure compound, but rather a mixture of salts. When dissolved in water, it forms a colorless to slightly yellow aqueous solution with a characteristic sulfur dioxide odor. As a powder or solid, it appears white and is highly water-soluble.
In technical terms, E228 is an acid salt—the potassium salt of sulfurous acid. When heated from 300-700°C, potassium bisulfite transforms into a molten form. Importantly, E228 is unstable when exposed to oxygen; it reacts over time to form potassium sulfate.
E228 is produced by passing sulfur dioxide gas through a solution of potassium carbonate until no more carbon dioxide evolves. The solution is then concentrated to obtain potassium bisulfite.
Where You’ll Find It
E228 appears in a wide range of beverages and processed foods:
• Wine and cider (primary use)
• Beer and other fermented beverages
• Dried fruits (apricots, raisins, peaches, apples, dates)
• Fruit juices (apple, grape, citrus) and soft drinks
• Canned vegetables and fruit (particularly mushrooms and vegetables)
• Baked goods and bread
• Jams, jellies, and marmalades
• Squashes and fruit concentrates
• Fresh mango chutney and preserved fruits
If you drink wine, beer, or consume dried fruit regularly, you’ve likely consumed E228 multiple times this week.
Why Do Food Companies Use It?
E228 performs four critical functions in food:
1. Fermentation control and sterilization: In wine and beer production, E228 is essential for controlling fermentation by inhibiting wild yeast and bacteria. It acts as a sterilizing agent that prevents secondary fermentation and spoilage, ensuring consistent product quality and stability.
2. Antioxidant protection: E228 acts as an oxygen scavenger, stopping oxidation that causes browning, discoloration, flavor loss, and nutrient degradation. This is why dried apricots retain their golden color rather than turning brown, and why wine maintains its color and flavor profile during storage.
3. Microbial growth inhibition: It prevents the growth of bacteria, molds, and unwanted fungi that would otherwise spoil beverages and foods, particularly important in fruit juices and soft drinks.
4. Color and flavor preservation: By preventing oxidation and microbial breakdown, E228 preserves the natural appearance and taste of foods, which is critical for maintaining consumer appeal.
Without E228, fermented beverages would have drastically shorter shelf lives, dried fruits would brown and deteriorate, and fruit juices would separate and develop off-flavors.
Is It Safe?
E228 is officially approved by major regulatory authorities, but with important safety considerations.
The FDA, EFSA, and UK Food Standards Authority all permit E228 in specific food categories with defined maximum use levels. The accepted daily intake (ADI) for all sulfites (E220-E228 group) is set at 0.7 mg/kg of body weight per day, expressed as sulfur dioxide equivalent.
Regulatory limits vary by product: wine typically allows up to 350-400 mg/L of sulfites, beer up to 250 mg/L, dried fruits up to 2000 mg/kg, and canned vegetables up to 100-250 mg/kg depending on type.
Who should avoid E228: Anyone with known sulfite sensitivity, asthma, or documented sulfite allergies must carefully read labels and avoid products containing E228. People with asthma are at highest risk for adverse reactions. However, individuals without asthma have also been documented with sulfite intolerance.
Historical Context: Regulatory Evolution
Sulfites, including potassium bisulfite, have been used in food preservation for centuries. However, as use expanded in the latter 20th century, particularly on fresh produce, documented cases of serious adverse reactions in people with asthma prompted regulatory action. In 1986, the FDA banned sulfites on fresh fruits and vegetables intended to be eaten raw, though certain exceptions were made for processed potatoes. This regulatory restriction was based on epidemiological evidence linking sulfite exposure to severe respiratory events in asthmatic patients. The requirement to label products containing sulfites followed shortly after. Today, E228 remains in use primarily in fermented beverages and processed foods where its preservative and antioxidant functions are essential, but its use is strictly regulated.
Natural vs Synthetic Version
E228 is produced industrially through synthesis:
Synthesis method: Created by passing sulfur dioxide gas through a solution of potassium carbonate (K₂CO₃) until no more carbon dioxide is evolved. The resulting solution is then concentrated to obtain potassium bisulfite. The sulfur dioxide itself can be derived from sulfur combustion or industrial processes.
Unlike some sulfite preservatives, E228 doesn’t have a “natural” source—it’s always produced through controlled chemical synthesis. However, the raw materials can be derived from natural or synthetic sources.
Once in your digestive system, E228 behaves identically regardless of the origin of its component materials. It dissociates into potassium ions and bisulfite ions, which are processed through standard metabolic pathways.
Natural Alternatives
Want to avoid E228? Food companies sometimes use these alternatives:
• Ascorbic acid (Vitamin C, E300): A natural antioxidant that slows browning and oxidation, though less effective for fermentation control
• Sorbic acid and sorbates (E200-E203): Another preservative class with antimicrobial properties, often used in combination with other additives
• Benzoic acid (E210): An antimicrobial preservative with different regulatory status in different regions
• Advanced technologies: Micro-oxygenation, modified atmospheric packaging, pasteurization, or electrodialysis (especially for wine production)
These alternatives often work differently or less effectively, and typically cost more or require additional processing, which is why E228 remains the industry standard for wine, beer, and dried fruit preservation.
The Bottom Line
E228 (potassium hydrogen sulfite) is a long-established liquid or powder preservative widely used in wine, beer, dried fruits, and other processed foods.
It’s particularly valued in fermented beverage production where it controls fermentation and prevents spoilage. Regulatory agencies worldwide have approved its use within specific limits, and it’s been used successfully for decades. However, people with asthma, allergies, or documented sulfite sensitivity must avoid it due to documented risks of serious respiratory and systemic reactions.
If you have asthma or suspect sulfite sensitivity, check product labels carefully and look for “sulfite-free” alternatives. The EU requires special labeling for products containing sulfites above 10 mg/kg. For the general population consuming these foods in normal amounts, E228 is considered safe within approved regulatory limits, though ongoing monitoring by food safety authorities continues.
