Without sulfur dioxide, the art of winemaking would be a gamble against oxidation and spoilage. For centuries, winemakers have harnessed sulfites to safeguard their work, and today sodium metabisulfite (Na2S2O5) stands as the most practical and widely used source of SO2 in cellars around the world. Whether you run a boutique organic vineyard or a high-volume industrial winery, understanding how to use sodium metabisulfite in wine making is fundamental to achieving consistency, stability, and longevity in every bottle.
Sodium metabisulfite is a white, crystalline powder that releases sulfur dioxide when dissolved in water or wine. Its twin functions—antioxidant and antimicrobial—are irreplaceable. As an antioxidant, it scavenges dissolved oxygen and inhibits the enzymes that cause browning, preserving the wine’s fruit character and color. As an antimicrobial, SO2 suppresses wild yeasts, acetic acid bacteria, and lactic acid bacteria that can turn a promising vintage into vinegar. By managing free SO2 levels with precision, you control the wine’s entire evolution from crush to cork.
Adding Na2S2O5 isn’t a one-size-fits-all operation. Dosage depends on the wine’s pH, the target molecular SO2, the stage of winemaking, and the existing free SO2 level. Below is a practical, chemistry-backed guide to using sodium metabisulfite effectively, including calculations, preparation methods, and timing.
Winemakers always speak in terms of free SO2 (ppm), but sodium metabisulfite contributes a specific yield of SO2. Pure Na2S2O5, molecular weight 190.1, contains 67.4% of its mass as SO2. That means 1 gram of sodium metabisulfite yields approximately 0.67 grams (670 mg) of SO2. In comparison, potassium metabisulfite yields only 57% SO2. This higher efficiency makes Na2S2O5 a cost-effective choice, especially for large-scale producers.
To calculate how much sodium metabisulfite to add for a desired SO2 addition, use this formula:
Weight of Na2S2O5 (grams) = (Desired SO2 addition in mg/L Ă— Volume in liters) Ă· 670
Example: You want to add 50 ppm (50 mg/L) SO2 to 1,000 liters of must.
Required Na2S2O5 = (50 Ă— 1,000) Ă· 670 = 74.6 grams. Round to 75 g for a practical addition.
While some winemakers add dry powder directly, preparing a liquid solution greatly improves dosing accuracy and safety. A 10% weight/volume (w/v) solution is standard: dissolve 100 g of food-grade sodium metabisulfite in enough distilled or deionized water to make a total volume of 1 liter. Always add the powder to the water, never the reverse, and stir until completely clear. This solution contains 67 g/L of SO2, meaning each milliliter provides about 67 mg SO2. For additions under 10 ppm, dilute the stock further. Store the solution in a sealed, light-proof container and use within one week, as SO2 can oxidize over time.
Because only the molecular fraction of SO2 is active against spoilage organisms, higher pH wines require significantly more free SO2 for the same protection. This is the single most important reason to monitor pH meticulously. Many winemakers keep a pH/SO2 chart in the cellar and adjust additions based on the day’s lab results. For instance, a high-pH Cabernet (pH 3.8) may need twice the free SO2 of a crisp Riesling (pH 3.0) to achieve the same antimicrobial effect. Using Na2S2O5 in conjunction with pH management is a hallmark of professional winemaking.
Sulfur dioxide can be introduced into wine in several forms: compressed SO2 gas, potassium metabisulfite (KMS), and sodium metabisulfite. Each has its place, but the sodium variant often wins on cost, convenience, and purity for high-volume production. Here’s a practical head-to-head comparison.
Compressed SO2 gas offers instantaneous dissolution and no metal cation addition, making it ideal for very large tanks where injecting gas via a sparging stone achieves rapid, even distribution. However, the equipment is expensive, cylinders require safe handling, and the gas itself poses severe respiratory risks. For the majority of wineries, granular or powdered metabisulfite is far easier to store, measure, and apply.
Both are white crystalline powders that release SO2 on dissolution. Potassium metabisulfite (KMS) is often favored in small-scale premium winemaking because potassium is already a natural component of wine and the added 0.53% potassium per gram of KMS is considered more “natural.” Sodium metabisulfite, on the other hand, contributes a tiny amount of sodium (about 0.24 g Na per gram of added Na2S2O5). In normal dosages up to 200 ppm SO2, the sodium increase is negligible and does not affect taste or wine stability. The real difference is economic: Na2S2O5 provides 18% more SO2 by weight than KMS. For a winery that uses 10 metric tons of metabisulfite per year, switching to sodium metabisulfite can reduce chemical costs by 10–15% while using fewer bags and less storage space.
Campden tablets are simply pre-measured tablets of potassium or sodium metabisulfite, sometimes with a binder. They are convenient for home winemakers and micro-wineries, but far too imprecise and costly for commercial use. For professional procurement, buying food-grade sodium metabisulfite in bulk is the standard.
While winemaking is a major application, sodium metabisulfite uses span across multiple industries. This wide demand spectrum makes it a strategic chemical for both suppliers and buyers who want a reliable, multi-grade product. As a sourcing manager, you can benefit from understanding the full landscape.
For each of these applications, Hailei Chemical supplies tailored grades—food grade (purity ≥97%) for wineries and food processors, and industrial grade (≥98%) for water treatment, mining, and pulp. The consistent quality and direct factory supply ensure you get exactly the specification your process demands.
When you search “sodium metabisulfite price” online, the bids you see vary widely. That’s because the price tag depends on more than just market trends. As a procurement manager at a winery, you need to know what you’re really paying for.
Food-grade Na2S2O5, required for winemaking, carries stricter heavy metal limits (lead < 2 ppm, arsenic < 1 ppm, mercury < 1 ppm) and must comply with FCC, JECFA, or EU E223 standards. Testing and certifications add cost. Industrial grade, while chemically similar in purity (98% vs 97%), may not be batch-tested for trace contaminants relevant to human consumption. Always request a Certificate of Analysis (CoA) that covers the parameters important for your wine.
The same chemical in 25 kg bags, 1,000 kg supersacks, or bulk tanker loads will have very different per-kg prices. Ocean freight, inland trucking, container space, and customs duties further shape the landed cost. At Hailei Chemical, we offer flexible packaging from 25 kg PE-lined woven bags to palletized 1-ton FIBCs, and we optimize logistics from our Shandong facility to reduce your total acquisition cost. Exploring current product specifications and bulk options can help you align volume with budget.
Sodium metabisulfite is produced by reacting sulfur dioxide with sodium carbonate (soda ash) or sodium hydroxide. Thus, global prices of sulfur and soda ash directly influence Na2S2O5 costs. When sulfur demand from phosphate fertilizers spikes, metabisulfite prices tend to follow. Working with a direct manufacturer like Hailei gives you earlier insight into these trends and more stable contract pricing than when buying through traders.
Cheapest isn’t always best. A slightly lower price might mask lower bulk density (meaning more bags needed), inferior dissolution characteristics, or inconsistent free SO2 yield. Smart buyers ran a small pilot test, comparing the effective SO2 content per dollar delivered to the cellar door. Often, they find that Hailei’s consistent high purity and dense granular form reduce handling losses and dosing errors, lowering the total cost of ownership.
Sodium metabisulfite bulk density is an often-overlooked specification that sneaks into your daily operations. Bulk density (the mass per unit volume of a powder, including the void spaces between particles) determines how many kilograms fit into a silo, a volumetric feeder, or a scoop. Commercial Na2S2O5 typically has a bulk density in the range of 1.0–1.2 g/cm³ for powder and 1.2–1.4 g/cm³ for dense granular forms. That translates to roughly 1,000–1,400 kg per cubic meter, with granular grades packing more tightly.
At Hailei Chemical, we can supply either a standard granular grade with good flow characteristics and high bulk density, or a fine powder for customers who prefer rapid dissolution in stock solution preparation. Always specify your preference when requesting a custom quotation.
For wine contact, only the best will do. Food-grade sodium metabisulfite must meet exacting criteria to ensure it doesn’t introduce off-flavors, heavy metals, or foreign particles into your wine. Here’s what to look for when evaluating a supplier’s CoA and quality system.
For wineries that also produce organic wines, note that sodium metabisulfite is permitted in organic winemaking in the EU and US, as long as the total sulfite content on the finished wine label is below the legal threshold (generally < 100 ppm for red, < 150 ppm for white). The additive itself need not be “organic” because it is a processing aid listed under 7 CFR 205.605(a).
Sodium metabisulfite is safe when handled with simple precautions, but the dust can irritate eyes, respiratory tract, and skin. Train your cellar staff to treat it with the same respect as any chemical:
As a purchasing manager, you need more than a good price—you need consistency, compliance, and a partner who understands the rhythm of the harvest season. Weifang Hailei Fine Chemical Co., Ltd. brings decades of manufacturing expertise to every kilogram of sodium metabisulfite we export. Our food-grade Na2S2O5 is specially produced to meet the needs of wineries worldwide, from small estate vineyards to multinational beverage companies.
Starting with a small trial order is the best way to experience our product’s fast dissolution, high SO2 yield, and uniform granulation under your own cellar conditions. Visit the sodium metabisulfite product page to learn more, and then reach out for a customized quotation that matches your volume and shipping destination. We’re here to help you protect every vintage from crush to bottle.
Ready to secure your supply? Use our Get a Quote form today, and a member of our team will respond with a detailed offer within one business day—including current sodium metabisulfite price per ton, shipping options, and a sample CoA for your review.