An unopened jar of tomato preserves has a shelf life of one to two years. An opened jar of tomato preserves remains safe to eat from one to 12 months, depending on various factors.
The shelf life of a jar of tomato preserves varies greatly depending on whether the preserves are commercially prepared or homemade, the amount of sugar and preservatives used in preparation, and consumer storage and handling. Commercially prepared preserves last longer than homemade preserves due to the use of preservatives and standardized preparation techniques. Preserves that contain large amounts of sugar last longer than those that contain small amounts of sugar. Storage and handling of preserves are major factors in their longevity as well. Refrigerated preserves last longer than those stored at room temperature. Minimizing the number of times the jar is opened also prolongs the life of the preserves.