Grey Poupon has a relatively long shelf life, generally lasting about two years when unopened. Once opened, it is recommended to use the mustard within several months to ensure the best flavor and quality. Most Dijon mustard, including Grey Poupon, can be stored in the refrigerator after opening to help maintain its freshness. It is important to always check the packaging for a "best by" date, which provides guidance on quality.
Although many consumers find that Grey Poupon remains good even after the recommended period, it is wise to assess the mustard visually and by smell, as any signs of spoilage indicate that it should be discarded. For specific details about storage or the best practices for Grey Poupon, one may look up the information on their official website.