Crystal sugar products have a useful life in excess of 2 years and thus do not require a ‘use by’ date. The only potential change of significance over a long period is physical caking.
Crystal sugars should be stored in dry areas, preferably avoiding large temperature variations and relative humidity above 70%. Sugar tends to absorb moisture from the air and may cake if subjected to unsuitable storage conditions. While stored, sugar is not normally attacked by insects or bacteria provided it is kept dry.
Brown and dark brown sugars can dry out if subjected to low humidity. Compression from storing as multiple layers of palletised product can alter the physical condition of these moist sugars.