Du bör inte återanvända lock, så att de ska komma i gott skick, även om du kan ge dem en visuell inspektion för bucklor, dingar och saknad tätningsmedel innan du använder dem.
Det låter dock som att dina burkar inte behandlas korrekt för att utveckla sina sälar om så många misslyckas. University of Missouri Extension tillhandahåller den här listan över saker som kan ha gått fel:
Failure to read and follow instructions on package for using bands and lids.
Leaving wrong amount of head space when filling jars.
Not removing particles of food, seeds, seasonings, or pulp of fruit from the top of jar before putting the lid on. Also, watch for threads from the cloth that is used to clean the rim of the jar.
Screwing band too tight can cause lid to buckle.
Not screwing band tight enough.
Insufficient heat to seal the lid.
Failure to exhaust (vent) steam - pressure canner for a full 10 minutes.
Letting pressure in canner fluctuate.
Reusing jars in which commercial food is sold.
Using warped, rusty, worn bands, or old commercial caps instead of home canning brands that are in good condition.
Reusing lids. The lid of a two - piece metal cap should not be used more than once.