• Rings may harbor moisture or food residue, leading to rust, mold, and vermin. Corroded bands may be difficult to remove.
• Rings may give you the false impression that the lids are still sealed properly. Spoilage may cause seals to break, so you always want to check that lids are intact and concave (indicating a vacuum seal) before opening jars from your pantry.
Thus, before storing canned goods, unscrew the rings, clean the lids and jars with a damp cloth, and dry thoroughly. (As long as the rings are in good shape and free of rust, they can be re-used in canning.)
If you're transporting the jars or giving them as gifts, you may leave the rings on until they are ready to be stored. Rings are sometimes used to hold decorative labels in place, but be sure to write the contents and date on the lids, as well.Related: Canning Basics: Tutorials, Recipes & More
(Images: Emily Ho)