Raisins can be stored, tightly sealed, at room temperature for several months, but to store longer (up to a year) seal the raisins in a plastic bag stored in the refrigerator. Tip: When adding raisins to batters for baked goods, coat the raisins with flour either individually or by shaking the raisins in a bag containing flour. Flour coated raisins will then stay suspended within the batter being prepared.