U-Konserve Insulated Food Jar Stainless Steel

Insulated food jars are designed to keep the temperature you start with, so it is recommended to pre-heat by pouring very hot water inside and letting sit for a few minutes before pouring out and adding your piping hot food, and pre-chilling in the freezer for a few minutes (lid off) before adding your cold food. U-Konserve food jars keep pre-heated food hot up to 5 hours, and pre-chilled food cold up to 8 hours (and often longer depending on the starting temperature and outside temperature).