Sodium metabisulfite (Na2S2O5) is the workhorse sulfiting agent in winemaking, yet many commercial operations still struggle with dosage, storage, and procurement. Whether you run a boutique estate or a high-volume cooperative, understanding how to use sodium metabisulfite in wine making correctly can mean the difference between a clean, age-worthy vintage and a batch lost to oxidation or microbial spoilage. In this comprehensive guide, we break down the chemistry, compare sulfur forms, and provide a step-by-step usage framework that every wine buyer, cellar master, and procurement manager needs.
Sodium metabisulfite uses in a winery extend far beyond simply adding “sulfite” to must. Its versatility makes it an essential chemical across every stage of vinification:
For a deeper look at industrial and food-grade applications beyond winemaking, visit our sodium metabisulfite product page to understand full specifications.
One of the first questions procurement teams ask is about the sulphur dioxide vs sodium metabisulfite choice. While both deliver SO2, the practical differences impact dosing accuracy, storage, and cost.
| Parameter | Sodium Metabisulfite (SMBS) powder/granules | Compressed SO2 gas or liquid | Potassium Metabisulfite |
|---|---|---|---|
| Typical SO2 release | ~67% by weight (1 g SMBS ≈ 0.67 g SO2) | 100% SO2 (pure) | ~57% by weight |
| Handling ease | Simple powder; dissolve in water | Requires pressurized cylinders, gas regulators, safety training | Similar to SMBS but lower SO2 yield |
| Cost per kg SO2 | Most economical for bulk use | Higher equipment and logistics cost | 15–25% more expensive than SMBS |
| Sodium addition | Adds ~33 mg Na per 100 mg SMBS; negligible in wine | None | Adds potassium, may contribute to tartrate precipitation |
| Storage stability | Stable if kept dry and cool; shelf life 12–18 months | Indefinite in sealed cylinders | Similar to SMBS |
For most wineries, sodium metabisulfite strikes the best balance of cost, ease of use, and minimal side effects. The tiny sodium increase is insignificant compared to the tartrate and pH impacts from potassium metabisulfite, especially in high-acid wines. Gas SO2 remains a niche solution for very large tanks with inline injection systems.
Precision matters. Here is exactly how to use sodium metabisulfite in wine making from crush to bottle.
Powder is difficult to weigh for small additions. Make a fresh 10% w/v solution:
Dissolve 100 g food-grade sodium metabisulfite in 1 liter of clean, chlorine-free water. This gives 10 g SMBS per 100 mL, equivalent to 6.7 g SO2 per 100 mL. Use immediately—SO2 degrades in solution within 24 hours. Store in a sealed container, no headspace.
Add 30–50 mg/L SO2 to crushed red must (50–75 mg/L SMBS) and 50–80 mg/L SO2 for white juice (75–120 mg/L SMBS). Higher doses for machine-harvested or damaged fruit. Stir thoroughly. Wait 4–12 hours before yeast inoculation to allow free SO2 to bind and native flora to die off.
After malolactic fermentation, maintain 20–30 mg/L molecular SO2 (target 0.5–0.8 mg/L molecular for reds, 0.8–1.2 mg/L for whites). Calculate using pH and temperature tables. Add SMBS solution slowly, mixing with a metering pump or via a Venturi in-line injector.
Adjust to 25–40 mg/L free SO2 depending on wine style and anticipated shelf life. For wines with residual sugar, keep free SO2 at the higher end to prevent refermentation. Use an SO2 analyzer to verify before and after bottling.
1 gram of 97% pure sodium metabisulfite provides ≈ 0.63 g SO2 (accounting for purity). To raise SO2 by 1 mg/L in 1,000 liters of wine: add 1.6 g SMBS. Always double-check using the formula:
SMBS required (g) = [Volume (L) × Desired SO2 increase (mg/L)] ÷ 630
Sodium metabisulfite bulk density is a critical but often overlooked parameter for winery logistics. Food-grade granular SMBS from Hailei Chemical typically has a bulk density of 1.2–1.4 g/cm³ (depending on granulation), which affects silo volume, bag stacking, and shipping costs.
Always request a bulk density specification from your supplier—inconsistent density can lead to dosing errors when measuring by volume rather than weight.
The sodium metabisulfite price fluctuates with raw material (soda ash and sulfur) costs, energy, and shipping. As of 2024–2025, food-grade FOB China prices hover between $350-$450 per metric ton for granular 97–98% purity. Factors influencing final landed cost for wineries include:
Working directly with a manufacturer like Hailei Chemical eliminates multi-layer distribution mark-ups. Our export-focused supply chain ensures competitive, transparent pricing with consistent quality. For a tailored quotation, request a quote today.
Not all metabisulfite is equal. Food-grade Na2S2O5 must meet strict purity and heavy metal limits to avoid off-flavors and meet food safety regulations in destination markets. Our typical certificate of analysis includes:
| Parameter | Specification (Food Grade) |
|---|---|
| Assay (Na2S2O5) | 97.0% min |
| SO2 content | 65.0% min |
| Iron (Fe) | ≤ 0.002% |
| Heavy metals (as Pb) | ≤ 5 ppm |
| Arsenic (As) | ≤ 2 ppm |
| Selenium (Se) | ≤ 5 ppm |
| pH (5% solution) | 4.0–4.8 |
| Clarity in water | Clear, free from insoluble matter |
We provide batch-specific COAs and can accommodate third-party testing. For premium wines, iron and copper levels are especially critical—excessive metals catalyze oxidation and haze formation.
Improper storage leads to SO2 loss and caking. Follow these rules:
While Na2S2O5 is indispensable, the industry is moving toward lower total sulfite loads. By using precise dosing and clean grapes, wineries can reduce additions while maintaining stability. On the procurement side, choose suppliers with robust environmental management—Hailei Chemical’s manufacturing adheres to ISO 14001 standards, minimizing waste and emissions. Bulk purchase in reusable 1,000 kg FIBCs further cuts packaging waste.
As a top-tier Chinese sodium metabisulfite exporter, Weifang Hailei Fine Chemical delivers food-grade quality that European and American winemakers trust. Our advantages include:
Ready to secure your sulfite supply for the next harvest? Visit our sodium metabisulfite page for full technical documentation, and then get a quote for your volume needs. Let’s raise a glass to perfectly stabilized wine.