Miso paste should be stored in an airtight container in the refrigerator to maintain its freshness and prevent contamination. Keeping it refrigerated slows the fermentation process, preserving its flavor and quality. Miso can last several months to over a year, depending on its type and storage conditions. With its shorter fermentation time, white miso may have a slightly shorter shelf life than red miso, which continues to develop its robust flavors over time. Always check for any changes in color, texture, or smell as spoilage indicators. Properly stored miso remains a reliable and flavorful ingredient for many delicious meals in your kitchen.