Gelatin can last for years but will lose potency after about 18 months. There are some tips to help you make your gelatin last as long as possible: 1. Keep it in a cool, dry place: If you store gelatin in a humid environment, it will absorb moisture from the air and become less effective. 2. Store it in an airtight container: If gelatin is exposed to air, it will start to break down and form clumps. 3. Keep it away from light: Light can also cause the gelatin to break down. 4. Don't let it come into contact with water or moisture: Water will cause the gelatin to dissolve.