Fresh Preserving Discussion Boards

In all the years that I've been canning (about ten or so), I've experienced my first product failure. When I was putting away this years goods, I noticed some of my 4oz jars of blackberry jelly from last year growing mold on top of the jelly where the jelly meets the side of the jar. I was shocked. That was a first for me.
The recipe was followed exactly, preparation, cooking time, head space, processing time, everything; and that still happened.
The seal was still intact and strong, and to the best of my observation, was in no way compromised.
The mint jelly though is good. I wondering that since the soft berries, like black and raspberries, tend to get moldy sooner even when bought from the grocery store, that even proper processing wouldn't even kill it all. The funny thing is I've never had this happen in the past and I've canned well over one hundred jars of jellies, jams, syrups and the like, and I've kept them longer than the suggested year like without any problems.
For curiosity, I have a jar of crabapple jelly that was processed from 1992 just to see how long the seal will last, though I would dare not eat it, and although darker in color, appears to look good yet.
I guess my record is still pretty good, but I'm literally stumped to as why.
Any and all input would be appreciated.

I find that very unusual since proper processing in a Boiling Water Canner should kill all mold, yeast and fungi spores and the vacuum seal prevents anything new from entering as long as the seal is intact.

It is possible that processing was not sufficient on this jelly, and/or there was an unusually high amount of bacteria in the fruit that your processing was not able to kill off. Only you know the answer and you need to look at your processing methods for possible weak areas.

If your processing time is only 5 minutes then I would review the method of sterilizing the jars beforehand. The canner should have a lid and maintain a full rolling boil for the prescribed time. Correct processing and high temperatures are critical to killing the spores.

Every once in awhile, it happens. I had more than a few jars of tomatoes go bad last year, just several days after processing them, for no apparent reason that I could determine. Chalk it up to a dose of bad luck that won't happen again for many years, and keep on chooglin'.

LMAO at the jelly from 1992 -- I, too, have a jar of red pepper jelly from the first batch of jelly I ever made, probably 1994 or thereabouts. It didn't jell *sigh* and I used it over cream cheese with crackers as an appetizer, but for whatever reason I still keep the one jar -- still perfectly sealed and no whiskers!