If you are using the full canning method, you can store homemade jam in a cool, dry place for up to two years. When I make jam, I like to enjoy it right away. After opening a jar, homemade jam will remain fresh in the refrigerator for up to two months. Freezing homemade jam in a freezer-safe airtight container is another great way to store it. It'll keep for up to one year.