Description
The parent compound of the sulfite preservative family, used directly as liquefied gas in winemaking and sugar refining where direct gas dosing offers cost and handling advantages over solid sulfite salts. Delivers identical antimicrobial, antioxidant, and enzymatic-browning-prevention functions as Sodium Metabisulfite at lower cost per unit SO2 equivalent.
Colorless liquefied gas under pressure or in cooled storage, with characteristic pungent odor. Highly water-soluble, generating sulfurous acid (H2SO3) and its dissociation products in solution.
We supply food-grade and industrial-grade Sulfur Dioxide from manufacturers in China holding ISO certifications relevant to the product and production.
Common market grades include Food Grade (FCC compliant) for winemaking and sugar refining, Pharmaceutical Grade meeting BP/USP specifications, and Industrial Grade for water treatment, pulp bleaching, and chemical synthesis.
Bulk shipment in pressure cylinders, ISO tanks, and dedicated road tankers. Batch-level COA covering assay, moisture, and impurities.
Introduction
Sulfur Dioxide has been used in winemaking for over two thousand years, originally generated by burning elemental sulfur inside wine vessels. Modern industrial Sulfur Dioxide is produced primarily as a byproduct of metal smelting (copper, zinc, and lead ore roasting) or by direct combustion of elemental sulfur in oxygen, followed by purification and liquefaction under pressure.
Regulated as E220 in the EU within the sulfite family (E220 through E228), classified as Generally Recognized as Safe by the U.S. FDA with the exception of use on fresh fruits and vegetables intended to be sold raw, and approved by JECFA with an Acceptable Daily Intake of 0.7 mg per kg body weight expressed as sulfur dioxide. Residual SO2 above 10 mg per kg must be declared on labels in the EU and US.
The compound delivers three simultaneous functions in food and beverage applications. Antimicrobial activity targets bacteria, yeasts, and molds at low pH, with the undissociated H2SO3 and molecular SO2 forms being the most active species. Antioxidant activity proceeds through oxygen scavenging and reduction of free radicals. Enzymatic-browning inhibition operates through irreversible inhibition of polyphenol oxidase, the enzyme responsible for fruit browning.
Strategic positioning is dominant in winemaking and remains irreplaceable in dried fruit and sugar refining. The principal constraint is sulfite allergy in a small fraction of the population, which has driven labeling requirements and ongoing reformulation toward reduced-sulfite or sulfite-free positioning in premium product segments.
Handling requires care: Sulfur Dioxide is corrosive to mucous membranes and respiratory tissue, requires sealed pressurized storage, and is regulated as a hazardous substance in transport.
Where it is used
- Winemaking: direct gas dosing into must and finished wine at large scale, the most cost-effective sulfiting method
- Sugar refining: clarification and decolorization of sugar syrups
- Dried fruit processing: fumigation of apricots, raisins, and other dried fruits prior to packaging
- Beer brewing: dissolved oxygen scavenging
- Fruit juice production: antioxidant and enzymatic-browning prevention
- Pulp bleaching and paper manufacturing
- Water treatment: dechlorination of process and waste water
- Pharmaceutical antioxidant in injectable formulations
- Chemical synthesis: feedstock for sulfite salts, sulfonates, and sulfuric acid
- Refrigerant in legacy industrial applications
Technical data
| Item | Specification |
|---|---|
| Appearance | Colorless liquefied gas under pressure |
| Assay (as SO2) | ≥ 99.9% |
| Moisture | ≤ 100 mg/kg |
| Non-volatile residue | ≤ 25 mg/kg |
| Selenium | ≤ 10 mg/kg |
| Heavy metals (as Pb) | ≤ 5 mg/kg |
| Arsenic | ≤ 3 mg/kg |
| Sulfuric acid | Passes test |
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