Let the soup come to room temperature, then transfer it into small containers to either freeze or refrigerate. If you plan on freezing it, you can keep it for a month. Just let it defrost a little before pouring into a pot to reheat. If you plan on putting the Phở broth in the fridge, it will last for 3 days. Make sure it's sealed well. At home, we just leave it all in the pot and bring it to a boil before we sleep. The lid goes on top and the next morning we boil it again to minimize the bacteria. We also only ever do this when the weather's cold!