Sesame seeds have a high oil content which means they are prone to going rancid. The best way to store them is in an airtight container, such as plastic freezer bags or jars, in the refrigerator or freezer. Vacuum packaging is also a good option. You can store raw sesame seeds for one year in the refrigerator or freezer. They will also store in a cool (55° -60° F), dark pantry for 6-12 months. Roasted sesame seeds can be stored for one to three years in the refrigerator or freezer and up to three years in a cool, dark pantry. Package the sesame seeds in quantities you will use in one month. Every time you open the jar or bag, the seeds are exposed to air and moisture which will reduce their shelf-life. The best way to tell if the sesame seeds have gone bad is by smell. As the oils break down they start to smell rancid and will taste pretty bad.