Balsamic Vinaigrette will keep for up to two weeks in your refrigerator. If the oil hardens on top, let it stand at room temperature for fifteen minutes before serving to give the the oil time to liquify. Then swirl or whisk the vinaigrette to combine and serve. My refrigerator is rarely without a pitcher of this salad dressing. And I predict that once you try it, you'll keep it on hand as well.