I have canned a lot in the past with with aa jar here and there. But the last year I have lost so much food to crowning of lids after they have sealed. I again lost 22 quarts of beautiful red beets. All sealed two days later the lids are swelling and crowned lost all 22 jars. We do have lime in our water and it seems to be stronger since the dry weather.
Since you don't describe your process in detail it`s impossible to figure out the exact cause of the spoilig. Most common mistakes while canning are:
- Improper sterilization of the glasses and lids.
- Too short or cold pasteurization of the canned vegetables. Time and temperature required are highly dependent on the type of canned good. For raw red beets it should be 45 min at 100°C, for pre-cooked 20 min at 100°C.
- Too much air remaing under the lid.
- Failing to create a vacuum for sealing, allowing micro-organisms to enter the glass.