What changes occur when ammonium sulfite is stored for an extended period?

Freshly produced ammonium sulfite typically contains over 85% to 90% of its content. However, the concentration gradually decreases with extended storage. Newly produced ammonium sulfite crystals exhibit larger intercrystalline voids and a loose structure. Over time, gravitational forces gradually compress these voids, resulting in compaction and increased product hardness. This is an inherent property of ammonium sulfite and not a quality issue. The product can still be used after physical fragmentation of the hardened blocks. Customers are advised to use the product within six months of its expiration date.