If you’re sourcing chemicals for food production, water treatment, or mining, you’ve likely asked: is sodium metabisulfite a preservative? The direct answer is yes – sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a highly effective food preservative, antioxidant, and antimicrobial agent. However, its role goes far beyond the food industry. This comprehensive guide examines how this versatile inorganic compound functions as a preservative, the critical influence of pH, why some people consider it harmful, what its Safety Data Sheet reveals, and the full range of industrial applications. Whether you are a procurement manager evaluating food-grade chemicals or an engineer specifying treatment chemicals, you’ll gain actionable insights to make informed sourcing decisions.
Hailei Chemical supplies both food-grade and industrial-grade sodium metabisulfite with a typical purity of 97–98%, backed by rigorous quality control and full documentation. Explore our sodium metabisulfite product page for detailed specifications, packaging options, and certifications.
Sodium metabisulfite is an inorganic compound that appears as a white or yellowish crystalline powder with a sharp sulfur dioxide odor. When dissolved in water and exposed to acid, it readily releases sulfur dioxide (SO2), the active preservative species. This mechanism underlies its widespread use in food and beverage preservation, where it performs two critical functions:
For food applications, sodium metabisulfite is classified as a “generally recognized as safe” (GRAS) substance when used within regulatory limits. Typical products preserved with sulfites include dried apricots, raisins, wine, bottled lemon juice, pickled foods, and some processed potato products. Its effectiveness as a preservative is highly dependent on several factors, especially pH, which we will examine next.
When buying sodium metabisulfite for preservation, it is essential to specify food-grade quality (minimum 97% purity) that meets FCC (Food Chemicals Codex) or EU food additive standards. Impurities such as heavy metals are strictly controlled. Hailei’s food-grade sodium metabisulfite is manufactured under ISO 9001‑certified processes and comes with a Certificate of Analysis for every shipment. Request technical data for our food‑grade Na2S2O5.
A common technical query from food technologists is: what is the pH of sodium metabisulfite and how does it influence preservative performance? A 1% aqueous solution of sodium metabisulfite typically exhibits a pH in the range of 4.0–5.0. The solution is mildly acidic, but the real preservative power is unlocked when it is introduced into a more acidic food matrix.
The chemical equilibrium of sulfur dioxide species is governed by pH:
Practical implication: for maximum preservation, sodium metabisulfite should be used in foods and beverages with a natural acidity below pH 4.5. Winemakers routinely adjust must pH to optimize SO2 performance; dried fruit processors often use a sulfite dip at low pH. If your product has a higher pH, you may require a higher dosage or a complementary preservative system.
Understanding this pH‑efficacy relationship helps formulators accurately dose sodium metabisulfite, avoiding both overuse (which can lead to off‑flavors and regulatory exceedances) and underuse (risk of spoilage). Our technical team can assist you in selecting the correct grade and providing usage guidance. Contact Hailei Chemical for formulation support.
Searches for “why is sodium metabisulfite bad for you” usually stem from legitimate health concerns. For the general population, sodium metabisulfite is safe at levels permitted in food. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an acceptable daily intake (ADI) of 0.7 mg per kg of body weight (expressed as SO2). Food manufacturers must comply with these limits, and typical residual SO2 levels in finished products are well within safe boundaries.
However, a small but significant portion of the population – particularly individuals with sulfite‑sensitive asthma – can experience adverse reactions. Sulfite sensitivity may cause symptoms ranging from mild wheezing and hives to severe bronchoconstriction and anaphylactoid reactions. Researchers estimate that 3–10% of asthmatics are sulfite‑sensitive. This is why regulatory agencies worldwide mandate clear labeling when sulfites are present at levels ≥10 ppm (FDA) or ≥10 mg/kg (EU). Foods containing sodium metabisulfite must declare “Contains Sulfites” on the label.
In addition to consumer health, occupational exposure presents hazards. The substance is classified as an irritant (EU Regulation 1272/2008) and can cause:
These risks are manageable with appropriate engineering controls, personal protective equipment (PPE), and adherence to the instructions in the Safety Data Sheet. For buyers, ensuring your workforce is trained on safe handling is a critical element of responsible procurement.
Far from being universally “bad,” sodium metabisulfite is an indispensable tool in food preservation when used correctly. The key is sourcing a consistent, high‑purity product and following all safety protocols – exactly what Hailei supports with every shipment.
Every responsible importer or user requests the sodium metabisulfite SDS before purchase. The Safety Data Sheet provides comprehensive hazard communication and safe handling guidance. Key sections every buyer should review include:
When comparing suppliers, request the latest SDS that specifically corresponds to the grade (food or industrial) you are purchasing. At Hailei Chemical, we provide up‑to‑date, REACH‑compliant SDS documents in multiple languages. Download our sodium metabisulfite SDS directly from the product page to verify all safety parameters before ordering.
While the question “is sodium metabisulfite a preservative” is common, the compound’s versatility extends into numerous high‑volume industrial processes. Here is a snapshot of the key sodium metabisulfite used for across industries:
Hailei Chemical supplies all these sectors with industrial‑grade sodium metabisulfite, packed in 25 kg PE‑lined bags, 1000 kg super sacks, or custom packaging. Our logistic capabilities include container loads, LCL shipments, and break‑bulk delivery to major ports worldwide. For detailed application‑specific specifications, visit our sodium metabisulfite product page.
Procuring food‑grade sodium metabisulfite means navigating a landscape of regulatory requirements, quality benchmarks, and logistical considerations. Here are the critical factors to evaluate:
Ready to place an order? Navigate to our detailed product page to review all specifications and request a personalised quote:
View Food-Grade & Industrial-Grade Sodium Metabisulfite Specifications
No. Sodium metabisulfite is a synthetic chemical and is not permitted in certified organic products under USDA NOP or EU organic regulations. Organic processors typically use alternatives like ascorbic acid or natural antioxidants.
In winemaking, sodium metabisulfite is often added at the crusher (50‑100 mg/L) and before bottling (30‑50 mg/L) to achieve a target free SO2 level of 25‑35 mg/L. Exact dosage depends on pH, wine style, and microbial load.
Both release SO2, and their preservative action is equivalent. Sodium metabisulfite provides 67% SO2 by weight, slightly more than potassium metabisulfite (57%). The choice often depends on cost and the cation’s impact on the final product (potassium can affect tartrate stability in wine).
Never. Industrial‑grade material may contain elevated levels of heavy metals and impurities not safe for human consumption. Always specify food‑grade (FCC/EU) with the appropriate purity and documentation.
You can download the latest REACH‑compliant SDS directly from our product page: Hailei Sodium Metabisulfite SDS. For large‑volume orders, we also provide customized safety documentation in your local language.
Still have questions? Our technical sales engineers are equipped with deep application expertise. Contact Hailei Chemical today for a customized consultation and a competitive quotation for your sodium metabisulfite requirements.
If you’re sourcing chemicals for food production, water treatment, or mining, you’ve likely asked: is sodium metabisulfite a preservative? The direct answer is yes – sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a highly effective food preservative, antioxidant, and antimicrobial agent. However, its role goes far beyond the food industry. This comprehensive guide examines how this versatile inorganic compound functions as a preservative, the critical influence of pH, why some people consider it harmful, what its Safety Data Sheet reveals, and the full range of industrial applications. Whether you are a procurement manager evaluating food-grade chemicals or an engineer specifying treatment chemicals, you’ll gain actionable insights to make informed sourcing decisions.
Hailei Chemical supplies both food-grade and industrial-grade sodium metabisulfite with a typical purity of 97–98%, backed by rigorous quality control and full documentation. Explore our sodium metabisulfite product page for detailed specifications, packaging options, and certifications.
Sodium metabisulfite is an inorganic compound that appears as a white or yellowish crystalline powder with a sharp sulfur dioxide odor. When dissolved in water and exposed to acid, it readily releases sulfur dioxide (SO2), the active preservative species. This mechanism underlies its widespread use in food and beverage preservation, where it performs two critical functions:
For food applications, sodium metabisulfite is classified as a “generally recognized as safe” (GRAS) substance when used within regulatory limits. Typical products preserved with sulfites include dried apricots, raisins, wine, bottled lemon juice, pickled foods, and some processed potato products. Its effectiveness as a preservative is highly dependent on several factors, especially pH, which we will examine next.
When buying sodium metabisulfite for preservation, it is essential to specify food-grade quality (minimum 97% purity) that meets FCC (Food Chemicals Codex) or EU food additive standards. Impurities such as heavy metals are strictly controlled. Hailei’s food-grade sodium metabisulfite is manufactured under ISO 9001‑certified processes and comes with a Certificate of Analysis for every shipment. Request technical data for our food‑grade Na2S2O5.
A common technical query from food technologists is: what is the pH of sodium metabisulfite and how does it influence preservative performance? A 1% aqueous solution of sodium metabisulfite typically exhibits a pH in the range of 4.0–5.0. The solution is mildly acidic, but the real preservative power is unlocked when it is introduced into a more acidic food matrix.
The chemical equilibrium of sulfur dioxide species is governed by pH:
Practical implication: for maximum preservation, sodium metabisulfite should be used in foods and beverages with a natural acidity below pH 4.5. Winemakers routinely adjust must pH to optimize SO2 performance; dried fruit processors often use a sulfite dip at low pH. If your product has a higher pH, you may require a higher dosage or a complementary preservative system.
Understanding this pH‑efficacy relationship helps formulators accurately dose sodium metabisulfite, avoiding both overuse (which can lead to off‑flavors and regulatory exceedances) and underuse (risk of spoilage). Our technical team can assist you in selecting the correct grade and providing usage guidance. Contact Hailei Chemical for formulation support.
Searches for “why is sodium metabisulfite bad for you” usually stem from legitimate health concerns. For the general population, sodium metabisulfite is safe at levels permitted in food. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an acceptable daily intake (ADI) of 0.7 mg per kg of body weight (expressed as SO2). Food manufacturers must comply with these limits, and typical residual SO2 levels in finished products are well within safe boundaries.
However, a small but significant portion of the population – particularly individuals with sulfite‑sensitive asthma – can experience adverse reactions. Sulfite sensitivity may cause symptoms ranging from mild wheezing and hives to severe bronchoconstriction and anaphylactoid reactions. Researchers estimate that 3–10% of asthmatics are sulfite‑sensitive. This is why regulatory agencies worldwide mandate clear labeling when sulfites are present at levels ≥10 ppm (FDA) or ≥10 mg/kg (EU). Foods containing sodium metabisulfite must declare “Contains Sulfites” on the label.
In addition to consumer health, occupational exposure presents hazards. The substance is classified as an irritant (EU Regulation 1272/2008) and can cause:
These risks are manageable with appropriate engineering controls, personal protective equipment (PPE), and adherence to the instructions in the Safety Data Sheet. For buyers, ensuring your workforce is trained on safe handling is a critical element of responsible procurement.
Far from being universally “bad,” sodium metabisulfite is an indispensable tool in food preservation when used correctly. The key is sourcing a consistent, high‑purity product and following all safety protocols – exactly what Hailei supports with every shipment.
Every responsible importer or user requests the sodium metabisulfite SDS before purchase. The Safety Data Sheet provides comprehensive hazard communication and safe handling guidance. Key sections every buyer should review include:
When comparing suppliers, request the latest SDS that specifically corresponds to the grade (food or industrial) you are purchasing. At Hailei Chemical, we provide up‑to‑date, REACH‑compliant SDS documents in multiple languages. Download our sodium metabisulfite SDS directly from the product page to verify all safety parameters before ordering.
While the question “is sodium metabisulfite a preservative” is common, the compound’s versatility extends into numerous high‑volume industrial processes. Here is a snapshot of the key sodium metabisulfite used for across industries:
Hailei Chemical supplies all these sectors with industrial‑grade sodium metabisulfite, packed in 25 kg PE‑lined bags, 1000 kg super sacks, or custom packaging. Our logistic capabilities include container loads, LCL shipments, and break‑bulk delivery to major ports worldwide. For detailed application‑specific specifications, visit our sodium metabisulfite product page.
Procuring food‑grade sodium metabisulfite means navigating a landscape of regulatory requirements, quality benchmarks, and logistical considerations. Here are the critical factors to evaluate:
Ready to place an order? Navigate to our detailed product page to review all specifications and request a personalised quote:
View Food-Grade & Industrial-Grade Sodium Metabisulfite Specifications
No. Sodium metabisulfite is a synthetic chemical and is not permitted in certified organic products under USDA NOP or EU organic regulations. Organic processors typically use alternatives like ascorbic acid or natural antioxidants.
In winemaking, sodium metabisulfite is often added at the crusher (50‑100 mg/L) and before bottling (30‑50 mg/L) to achieve a target free SO2 level of 25‑35 mg/L. Exact dosage depends on pH, wine style, and microbial load.
Both release SO2, and their preservative action is equivalent. Sodium metabisulfite provides 67% SO2 by weight, slightly more than potassium metabisulfite (57%). The choice often depends on cost and the cation’s impact on the final product (potassium can affect tartrate stability in wine).
Never. Industrial‑grade material may contain elevated levels of heavy metals and impurities not safe for human consumption. Always specify food‑grade (FCC/EU) with the appropriate purity and documentation.
You can download the latest REACH‑compliant SDS directly from our product page: Hailei Sodium Metabisulfite SDS. For large‑volume orders, we also provide customized safety documentation in your local language.
Still have questions? Our technical sales engineers are equipped with deep application expertise. Contact Hailei Chemical today for a customized consultation and a competitive quotation for your sodium metabisulfite requirements.
If you’re sourcing chemicals for food production, water treatment, or mining, you’ve likely asked: is sodium metabisulfite a preservative? The direct answer is yes – sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is a highly effective food preservative, antioxidant, and antimicrobial agent. However, its role goes far beyond the food industry. This comprehensive guide examines how this versatile inorganic compound functions as a preservative, the critical influence of pH, why some people consider it harmful, what its Safety Data Sheet reveals, and the full range of industrial applications. Whether you are a procurement manager evaluating food-grade chemicals or an engineer specifying treatment chemicals, you’ll gain actionable insights to make informed sourcing decisions.
Hailei Chemical supplies both food-grade and industrial-grade sodium metabisulfite with a typical purity of 97–98%, backed by rigorous quality control and full documentation. Explore our sodium metabisulfite product page for detailed specifications, packaging options, and certifications.
Sodium metabisulfite is an inorganic compound that appears as a white or yellowish crystalline powder with a sharp sulfur dioxide odor. When dissolved in water and exposed to acid, it readily releases sulfur dioxide (SO2), the active preservative species. This mechanism underlies its widespread use in food and beverage preservation, where it performs two critical functions:
For food applications, sodium metabisulfite is classified as a “generally recognized as safe” (GRAS) substance when used within regulatory limits. Typical products preserved with sulfites include dried apricots, raisins, wine, bottled lemon juice, pickled foods, and some processed potato products. Its effectiveness as a preservative is highly dependent on several factors, especially pH, which we will examine next.
When buying sodium metabisulfite for preservation, it is essential to specify food-grade quality (minimum 97% purity) that meets FCC (Food Chemicals Codex) or EU food additive standards. Impurities such as heavy metals are strictly controlled. Hailei’s food-grade sodium metabisulfite is manufactured under ISO 9001‑certified processes and comes with a Certificate of Analysis for every shipment. Request technical data for our food‑grade Na2S2O5.
A common technical query from food technologists is: what is the pH of sodium metabisulfite and how does it influence preservative performance? A 1% aqueous solution of sodium metabisulfite typically exhibits a pH in the range of 4.0–5.0. The solution is mildly acidic, but the real preservative power is unlocked when it is introduced into a more acidic food matrix.
The chemical equilibrium of sulfur dioxide species is governed by pH:
Practical implication: for maximum preservation, sodium metabisulfite should be used in foods and beverages with a natural acidity below pH 4.5. Winemakers routinely adjust must pH to optimize SO2 performance; dried fruit processors often use a sulfite dip at low pH. If your product has a higher pH, you may require a higher dosage or a complementary preservative system.
Understanding this pH‑efficacy relationship helps formulators accurately dose sodium metabisulfite, avoiding both overuse (which can lead to off‑flavors and regulatory exceedances) and underuse (risk of spoilage). Our technical team can assist you in selecting the correct grade and providing usage guidance. Contact Hailei Chemical for formulation support.
Searches for “why is sodium metabisulfite bad for you” usually stem from legitimate health concerns. For the general population, sodium metabisulfite is safe at levels permitted in food. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an acceptable daily intake (ADI) of 0.7 mg per kg of body weight (expressed as SO2). Food manufacturers must comply with these limits, and typical residual SO2 levels in finished products are well within safe boundaries.
However, a small but significant portion of the population – particularly individuals with sulfite‑sensitive asthma – can experience adverse reactions. Sulfite sensitivity may cause symptoms ranging from mild wheezing and hives to severe bronchoconstriction and anaphylactoid reactions. Researchers estimate that 3–10% of asthmatics are sulfite‑sensitive. This is why regulatory agencies worldwide mandate clear labeling when sulfites are present at levels ≥10 ppm (FDA) or ≥10 mg/kg (EU). Foods containing sodium metabisulfite must declare “Contains Sulfites” on the label.
In addition to consumer health, occupational exposure presents hazards. The substance is classified as an irritant (EU Regulation 1272/2008) and can cause:
These risks are manageable with appropriate engineering controls, personal protective equipment (PPE), and adherence to the instructions in the Safety Data Sheet. For buyers, ensuring your workforce is trained on safe handling is a critical element of responsible procurement.
Far from being universally “bad,” sodium metabisulfite is an indispensable tool in food preservation when used correctly. The key is sourcing a consistent, high‑purity product and following all safety protocols – exactly what Hailei supports with every shipment.
Every responsible importer or user requests the sodium metabisulfite SDS before purchase. The Safety Data Sheet provides comprehensive hazard communication and safe handling guidance. Key sections every buyer should review include:
When comparing suppliers, request the latest SDS that specifically corresponds to the grade (food or industrial) you are purchasing. At Hailei Chemical, we provide up‑to‑date, REACH‑compliant SDS documents in multiple languages. Download our sodium metabisulfite SDS directly from the product page to verify all safety parameters before ordering.
While the question “is sodium metabisulfite a preservative” is common, the compound’s versatility extends into numerous high‑volume industrial processes. Here is a snapshot of the key sodium metabisulfite used for across industries:
Hailei Chemical supplies all these sectors with industrial‑grade sodium metabisulfite, packed in 25 kg PE‑lined bags, 1000 kg super sacks, or custom packaging. Our logistic capabilities include container loads, LCL shipments, and break‑bulk delivery to major ports worldwide. For detailed application‑specific specifications, visit our sodium metabisulfite product page.
Procuring food‑grade sodium metabisulfite means navigating a landscape of regulatory requirements, quality benchmarks, and logistical considerations. Here are the critical factors to evaluate:
Ready to place an order? Navigate to our detailed product page to review all specifications and request a personalised quote:
View Food-Grade & Industrial-Grade Sodium Metabisulfite Specifications
No. Sodium metabisulfite is a synthetic chemical and is not permitted in certified organic products under USDA NOP or EU organic regulations. Organic processors typically use alternatives like ascorbic acid or natural antioxidants.
In winemaking, sodium metabisulfite is often added at the crusher (50‑100 mg/L) and before bottling (30‑50 mg/L) to achieve a target free SO2 level of 25‑35 mg/L. Exact dosage depends on pH, wine style, and microbial load.
Both release SO2, and their preservative action is equivalent. Sodium metabisulfite provides 67% SO2 by weight, slightly more than potassium metabisulfite (57%). The choice often depends on cost and the cation’s impact on the final product (potassium can affect tartrate stability in wine).
Never. Industrial‑grade material may contain elevated levels of heavy metals and impurities not safe for human consumption. Always specify food‑grade (FCC/EU) with the appropriate purity and documentation.
You can download the latest REACH‑compliant SDS directly from our product page: Hailei Sodium Metabisulfite SDS. For large‑volume orders, we also provide customized safety documentation in your local language.
Still have questions? Our technical sales engineers are equipped with deep application expertise. Contact Hailei Chemical today for a customized consultation and a competitive quotation for your sodium metabisulfite requirements.
When sourcing chemical agents for water treatment, gold mining, or food preservation, the properties of sodium bisulfite are frequently the first technical checkpoint. In professional industrial procurement, “sodium bisulfite” almost always refers to sodium metabisulfite (Na₂S₂O₅), the anhydrous and more stable form that instantly generates bisulfite ions upon dissolution. A sound grasp of these properties—from molecular structure to storage behavior—empowers buyers to specify the correct grade, avoid handling pitfalls, and optimize process efficiency. At Hailei Chemical, we supply food-grade and industrial-grade sodium metabisulfite with 97–98% purity, backed by rigorous quality control and global logistics expertise.
Industrial buyers often encounter the term “sodium bisulfite” on tender documents and spec sheets, yet the shipped product is routinely sodium metabisulfite. This is not a discrepancy; it reflects the aqueous chemistry of the two compounds. Sodium metabisulfite (Na₂S₂O₅) is a stable, crystalline powder that, when dissolved in water, undergoes hydrolysis to yield two equivalents of sodium bisulfite (NaHSO₃):
Na₂S₂O₅ + H₂O → 2 NaHSO₃
In practice, the properties of sodium bisulfite as experienced in solution are realized from sodium metabisulfite. For this reason, the chemical industry uses the names interchangeably for many applications, although the dry storage and handling characteristics clearly belong to metabisulfite. Procurement professionals who understand this relationship can write clearer specifications and avoid confusion with true sodium bisulfite solutions, which are less stable and more expensive to transport.
Searching for the sodium metabisulfite molecular formula must return one definitive answer: Na₂S₂O₅. The substance carries CAS number 7681-57-4 and a molecular weight of 190.11 g/mol. Its structure centers on a disulfite ion (S₂O₅²⁻), where two sulfur atoms are linked by a direct S–S bond, each additionally bound to three oxygen atoms. This configuration imparts a high reducing potential and the ability to release sulfur dioxide (SO₂) under acidic conditions or heating.
The crystalline solid is white to yellowish-white and appears as free-flowing granules or powder in commercial grades. When evaluating supplier specifications, confirming the exact CAS and molecular formula is the first step toward verifying material identity—critical in regulated industries such as food processing and potable water treatment.
Procurement managers and plant engineers need a clear profile of the physical properties of sodium bisulfite/metabisulfite to design safe receiving, storage, and feeding systems. Below are the key parameters that influence day-to-day operations:
Redox chemistry is the heart of sodium metabisulfite’s industrial value, and the properties of sodium bisulfite in an aqueous medium define its practical reactivity. Once dissolved, the bisulfite ion acts as a powerful reducing agent, participating in reactions that are central to water treatment, mining, and food preservation.
In water and wastewater plants, bisulfite is employed to neutralize free chlorine and chloramine residuals. The reaction is rapid and stoichiometric:
NaHSO₃ + Cl₂ + H₂O → NaHSO₄ + 2 HCl
About 1.46 kg of pure sodium metabisulfite is required to remove 1 kg of chlorine. Understanding this ratio allows operators to size dosing equipment accurately. The ability to achieve undetectable chlorine residuals without introducing toxic byproducts makes the material indispensable in reverse osmosis pretreatment and effluent dechlorination.
One of the most critical safety applications of sodium metabisulfite is the destruction of free cyanide in gold leach tailings. The bisulfite ion, together with an oxygen source (usually air), oxidizes cyanide to the far less toxic cyanate:
CN⁻ + S₂O₅²⁻ + O₂ + H₂O → CNO⁻ + 2 SO₄²⁻ + 2 H⁺
Mine site laboratories regularly monitor ORP (oxidation-reduction potential) to confirm that enough metabisulfite has been added. The dose depends on the cyanide concentration but typically ranges from 2 to 8 grams of sodium metabisulfite per gram of free cyanide. Buyers in this sector place a premium on high purity and low heavy metal levels to meet stringent environmental compliance.
The food industry relies on the sodium metabisulphite in food as a preservative (E223) with antioxidant and antimicrobial functions. In solution, the bisulfite ion scavenges oxygen and inhibits enzymatic browning in dried fruits, fruit juices, and wine. The active species reacts with carbonyl compounds to form stable sulfonates, preserving color and freshness. The permitted residual SO₂ level in food products varies by regulation—for example, the EU allows up to 200 mg/kg in certain dried fruits—so food processors must select a certified food-grade powder with guaranteed purity and minimal arsenic, lead, and selenium content.
Sodium metabisulfite uses in winemaking deserve special attention. Winemakers prefer potassium metabisulfite for routine sulfite additions, but sodium metabisulfite is occasionally used for cleaning and sanitizing equipment, and in some regions for must sulfiting where potassium buildup is not a concern. The bisulfite ion releases free SO₂, which acts as an antimicrobial agent against wild yeasts and bacteria and as an antioxidant to prevent oxidative spoilage. The amount needed depends on pH—lower pH requires less free SO₂ to achieve the same molecular SO₂ concentration. A winery procurement team sourcing sodium metabisulfite must demand a purity of at least 97% and ensure the product is free from foreign odors that could taint wine.
In pulp mills, sodium metabisulfite serves as a reducing bleach assistant, especially in mechanical pulping where it brightens lignin-rich pulp without degrading fiber strength. The bisulfite ion reduces chromophoric groups, enhancing brightness. Similarly, in textile finishing, a mild bisulfite rinse removes residual chlorine from fabrics after hypochlorite bleaching, preventing yellowing and fiber degradation. The properties of sodium bisulfite as a chlorine scavenger make it a cost-effective alternative to activated carbon in many post-bleach baths.
A thorough understanding of commercial specifications prevents costly non-conformances. At Hailei Chemical, we supply industrial and food grades with the following typical parameters :
| Parameter | Industrial Grade | Food Grade (E223) |
|---|---|---|
| Purity (as Na₂S₂O₅) | 97.0% min | 97.5–98.0% min |
| SO₂ Content | 65.0% min | 65.0% min |
| Iron (Fe) | ≤ 0.005% | ≤ 0.001% |
| Heavy Metals (as Pb) | ≤ 0.002% | ≤ 0.001% |
| Arsenic (As) | ≤ 0.0002% | ≤ 0.0002% |
| Selenium (Se) | — | ≤ 0.003% |
| pH (5% solution) | 4.0–5.0 | 4.0–5.0 |
| Water Insoluble | ≤ 0.05% | ≤ 0.02% |
Buyers serving regulated markets—especially beverage, dairy, or municipal drinking water—should request a Certificate of Analysis (CoA) for each lot and verify compliance with FCC, JECFA, or EU standards as appropriate. Our quality management system ensures batch traceability from production to shipment.
The physical and chemical properties of sodium metabisulfite dictate specific packaging and storage protocols to preserve product integrity. Standard packaging includes 25 kg woven polypropylene bags with an inner polyethylene liner, 1000 kg FIBC bulk bags, and drums for smaller quantities. The liner must provide a robust moisture barrier because even slight humidity ingress triggers decomposition, leading to caking and SO₂ loss.
Warehouse conditions should maintain temperatures below 30 °C and relative humidity below 60%. Stacking should allow air circulation, and opened bags must be re-sealed promptly. Under these conditions, the shelf life ranges from 12 to 24 months depending on initial purity and packaging integrity. In tropical and monsoon climates—such as those in Bangladesh where interest in sodium metabisulfite price in bangladesh is growing—suppliers must offer packaging with enhanced moisture protection and possibly arrange container liners for sea freight to prevent deterioration during transit.
Chemical importers in South Asia closely watch the sodium metabisulfite price in bangladesh due to the country’s expanding textile, leather, and food processing sectors. Prices are influenced by international sulfur and soda ash feedstock costs, shipping freight, and local duties. A reliable long-term supplier like Hailei Chemical can provide stable pricing through direct factory contracts, flexible CIF Chittagong or Mongla terms, and volume flexibility from FCL to break-bulk shipments. When evaluating price quotations, buyers should consider the total delivered cost, including moisture-proof packaging and demurrage risks, not just the EXW price per metric ton.
Responsible buyers integrate EHS (Environment, Health, Safety) criteria into sourcing decisions. Sodium metabisulfite is classified as an irritant, and its solid form can cause eye and respiratory irritation. Proper PPE includes dust masks, goggles, and gloves. Under REACH and GHS, it carries H318 (causes serious eye damage) and H302 (harmful if swallowed) hazard statements. Our Safety Data Sheets (SDS) are always supplied with shipments and available for review before purchase.
On the environmental side, bisulfite ions oxidize to sulfate in wastewater, a benign species at typical discharge concentrations. When used in cyanide destruction, the resulting cyanate further hydrolyzes to ammonia and carbonate, dramatically reducing ecotoxicity. This green chemistry aspect makes sodium metabisulfite a preferred choice over chlorine-based cyanide oxidizers, which can form toxic cyanogen chloride.
A well-written purchase order prevents costly discrepancies. Based on the properties of sodium bisulfite outlined, include these details:
Our team at Hailei Chemical will provide a detailed technical data sheet for each shipment, aligning with these parameters to make your incoming inspection seamless.
With over a decade of experience exporting to more than 40 countries, Weifang Hailei Fine Chemical Co., Ltd. combines manufacturing control with supply chain reliability. Our product consistency is validated by ISO-certified management systems, while our logistics team handles the complexities of hazardous goods documentation (Class 8 for some concentrations) and customs clearance. We offer sample evaluation, contract manufacturing, and monthly production capacity of 3,000 MT to support large-scale industrial demands.
Whether you need sodium metabisulfite uses in winemaking or high-tonnage deliveries for a gold mining operation, our technical service engineers are available to assist with application-specific recommendations. We understand that the sodium metabisulfite molecular formula on paper must translate into consistent real-world performance.
Choosing the right sodium metabisulfite grade begins with a clear understanding of its physical and chemical properties. Let our experts help you match those specifications to your process requirements. Request a competitive quotation for industrial or food-grade sodium metabisulfite, including tailored packaging and delivery to your port. We look forward to powering your success with reliable chemistry and global reach.