To store your fresh or frozen berries coulis, allow it to cool completely and then transfer it to an airtight container. Keep it refrigerated, where it should stay fresh for up to a week. If you have made a larger batch and don't plan to use it all within a week, consider freezing it in smaller portions. I like to use silicone ice cube trays for this purpose, making it easier to defrost only the amount you need at a time.