Check canners at the beginning of each canning session, making sure all parts are in the proper working condition.
Water Bath (Boiling Water) Canner
Occasionally, the rack for a water bath (boiling water) canner becomes corroded after repeated use. It should be replaced as needed. Check the canner base for dents or warping that might interfere with heat distribution. Also, check for pinholes that can cause leaking. Replace defective parts.
Pressure (Steam Pressure) Canner
Examine all parts of the canner. Canners fitted with replaced gaskets and safety valves must be examined carefully and all parts that show signs of cracking or warping must be replaced. Clean the vent pipe of any residue that might block the passage of steam; check for any warping of the lid or canner base; and make sure the canner lid locks securely. If using a dial gauge canner, have the gauge tested annually for accuracy before your first canning session.