Store homemade hummus with sumac in an airtight container in the fridge for up to 4 days. We recommend garnishing the hummus with parsley just before serving though, as the parsley will wilt and lose its appeal if stored for longer than a couple of hours. You can also freeze hummus for up to 2 months in an airtight container. Simply make sure not to fill the container to the brim, as hummus tends to expand a bit when freezing.