Invertase is an enzyme which gradually converts sucrose into invert sugar (equal parts of glucose and fructose) - a form of sugar which does not readily crystallise and is also hygroscopic. It also tends to impart this property to its environment. Its active component is the enzyme Beta-Fructosidase (derived from yeast cells) carried in Glycerol, and its enzymic activity is always constant. In storage, its container must be kept sealed and it should be kept cool (or preferably refrigerated), where its shelf-life will be at least 12 months. For more information on sugars and gelling agents click here.