Storage: Transfer the dressing to an airtight container with a lid. Place the container in the refrigerator. Store in the refrigerator for up to a week. Before serving, give the dressing a good stir as the ingredients may separate and settle. If the dressing is too thick after being stored, you can thin it out with a little bit of buttermilk. If you notice any changes in the appearance or smell of the dressing, discard it immediately.