Yes, Jell-O expires. All Jell-O packages have a "use by" date printed on the package. To ensure the freshest product with the best taste and texture, Jell-O should be used before the "use by" date.
Whipped Jell-O jars are a deliciously different way of serving Jell-O to guests. In this recipe, four different flavors of Jell-O gelatin are needed. Each flavor is made one at a time. After 30 minutes in the refrigerator, the Jell-O is removed and beaten with a mixer for two minutes, then spooned into clear glass jelly jars. Each layer must be set before adding the next. The end result is a decorative and delicious Jell-O rainbow.