Does Sodium Metabisulfite Expire?
Yes, sodium metabisulfite does expire. Over time, it can degrade and lose effectiveness, especially if it is exposed to moisture, air, or high temperatures. This chemical gradually breaks down to form sodium sulfate and sulfur dioxide, which reduces its ability to act as a preservative or sanitizing agent.
- Shelf Life: Unopened and properly stored sodium metabisulfite typically has a shelf life of 1 to 3 years.
- Storage: Keep it in a tightly sealed container in a cool, dry place to maximize its lifespan.
- Signs of Expiry: If it becomes clumpy, yellowish, or has a weaker sulfur smell, it may have degraded.
If you are unsure about its potency, it is safer to use a fresh batch, especially for food, winemaking, or sterilization purposes.
