The key to maximizing the shelf life of pemmican is to keep it in a cool, dark, and dry place. When stored in these conditions (such as in an airtight container in your pantry), the pemmican should last at least 6-12 months. If your region is particularly humid and hot (think Florida), then you are probably better off storing pemmican in the refrigerator. Better safe than sorry! If you want to store pemmican for long periods of time (such as for emergency food), then you will need to package it in Mylar bags with oxygen absorbers - but it will need to be incredibly dry. You can read how to do this here.