Potassium metabisulfite

Potassium Metabisulfite (K2S2O5) is a versatile chemical primarily used as an antioxidant and preservative. In the wine and beverage industry, it is essential for inhibiting the growth of wild yeast and bacteria while preventing oxidation to preserve color and flavor. In industrial settings, it serves as a reducing agent for textile dyeing, a dechlorinating agent in water treatment, and a developer component in photography. For B2B buyers, it is crucial to specify the purity level (typically 96% to 99%) based on whether the application is food-grade or technical-grade.

For food-grade applications, the product must comply with FCC (Food Chemicals Codex) or E224 (EU Food Additive) standards. Ensure the supplier provides a Certificate of Analysis (COA) for every batch, detailing levels of heavy metals (like Lead and Arsenic) and Iron content, which must be within strictly defined limits. Additionally, verify that the manufacturer holds ISO 9001 for quality management and HACCP or ISO 22000 if the product is intended for the food supply chain.

Buyers should evaluate the solubility and SO2 (Sulfur Dioxide) content, which is the active component (usually around 57% min). The product is highly sensitive to moisture; therefore, technical compatibility depends on the packaging integrity. Look for PE-lined woven bags or airtight plastic drums to prevent caking and loss of potency. For large-scale industrial use, request information on the particle size distribution to ensure consistent dissolution rates in your processing tanks.

Potassium Metabisulfite is generally classified as a non-flammable solid, but it is an irritant and can release toxic SO2 gas if it contacts acids. You must ensure the supplier provides a valid MSDS (Material Safety Data Sheet) and complies with IMDG codes for sea freight. When shipping to international markets, confirm that the packaging is UN-certified to prevent leakage, as many customs authorities will reject chemical shipments with damaged or non-compliant containers.

To secure your transaction, utilize Trade Terms that include third-party inspections (such as SGS or Intertek) before the balance payment is made. When sourcing via Made-in-China.com, prioritize Audited Suppliers who have undergone on-site verification. Always request a pre-shipment sample from the actual production lot and compare its laboratory results against the final bulk delivery to prevent 'quality fade'.

Prices for Potassium Metabisulfite are often tied to the market price of Potassium Carbonate and Sulfur. Negotiate based on volume tiers, as ordering in full container loads (FCL) significantly reduces the per-unit shipping cost and allows for better leverage on the FOB price. Ensure the contract explicitly states the shelf life (usually 12-24 months) and includes a claims clause for products that arrive caked or with degraded SO2 levels due to poor sealing.