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Jun 21, 2008 09:13 AM

Canning jars not sealed

I made several batches of plum jam and some of the jars did not seal.
Can I replace the lids and process in a water bath without reheating the contents of the jar?
If so do I place the jars in warm water and then proceed to heat them??

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  1. Remove the lids that didn't seal, wipe the rim of the jars with a clean, damp cloth and replace with new lids. Screw on the bands and process. That should work. The contents of the jars will be sterilized by processing so no need to re-boil the jam. It's possible that the jars themselves are the culprit - so check the rims very carefully for any nicks or chips.

    1. If you want to recan them I'd recommend heating the jam back up to the boil and going through the process again: hot jam, hot sterilized jars and lids. The point of having everything hot is to kill the nasties that can invade your preserved food and ruin it (and you). My experience is jars that don't seal A) had a bit of jam left on the rim that didn't get wiped off, B) the lid had a faulty gum seal, C) the jars were overfilled. Inspect your lids, new or not, to make sure the gum seal is good before using them. Pay attention when wiping the rims of the jars to make sure everything is off. Leave the recommended amount of head space because the contents of overfilled jars in the water bath can bubble over and seep through the lid causing a faulty seal.

      If you really can't face going through the whole process again, heat the jam back up and pour it into freezer containers and freeze.

      1. First of all, when did you make the jam? This morning? I find that sometimes jars that seem not to have sealed will have done so by the next day after they've had a chance to cool completely. You can also try pressing hard on the lid; if it stays indented, the seal is fine.

        If I were going to reprocess the jam, I'd use new jars as well as new lids. As Nyleve says, it could well be that there was some kind of defect in the jar or the tiniest chip in the rim that was keeping it from sealing. I wouldn't chance going through it all again just to have the same jars still not form a seal.

        You say you made "several" batches and "some" jars didn't seal. If you had a problem with more than one jar in any one batch, you might have a problem with your canning procedure somewhere along the line. There are so many reasons jars might not seal: a fault in either the jar or the lid, jars filled to much or too little, trapped air not removed, jar rims not wiped, not enough water in the processing bath or not enough time spent in the bath. If more than just one or two jars didn't seal, it would probably be a good idea to analyze your canning technique in some detail and make sure you're not doing something that's causing the problem.

        1. Put a couple of jars in the fridge. They will keep there just fine for quite a long time. In the canning supplies of most groceries etc. you can find food grade parafin intended for sealing jams and jellies. Follow the instructions to melt and then pour a thin layer on top of your cool jam. It will harden and seal the jar. I would not re-heat and re-process the jam. The quality will be compromised.

          14 Replies
          1. re: Candy

            Fridge, yes; paraffin, no. The use of paraffin wax to seal jars of jam, something all our grandmothers did, is no longer recommended. It's one of the reasons food-grade paraffin is so hard to find these days. And reprocessing the jam won't necessarily compromise quality. I've done it when necessary and the reprocessed is indistinguishable from the first batch.

            1. re: JoanN

              It is readily available on my grocery shelves and I've never had a problem with it. It is still commonly in use here. I guess one more item for the food police. Works for me and as long as I can get it I'll use it. I only use it for jams and jellies.

              1. re: Candy

                I will add, that problems occured when the parafin was not evenly applied and there was incomplete coverage. If you are going to use it be sure no jam or jelly is uncovered by the wax.

              2. re: JoanN

                In the canning classes I've taken wax was really considered a no-no, along with the method of sealing jars by flipping them upside down. Why not just reprocess the jars (it's just jam!) or eat them or freeze them? Three options and they're all easy, and none of them are considered food safety threats. Wax is.

                1. re: Vetter

                  Even when I began cooking - and I'm not quite a seniour yet - wax was certainly considered a reasonable option for sealing jars of jam or jelly. I did it myself that way a few times. When the wax-sealed jars went funny, you could usually tell. There would be mold underneath or the jam would leak out around the edges of the wax. Frankly, I didn't think it was all that convenient or easy - and definitely not entirely reliable. There would always be a jar or two that would go bad.

                  After that, when making cooked jams or jellies, I would use proper canning jars with new lids. Washed well, then boiled to sterilize (and left in a warm oven to stay hot). Fill the jars, put on the lids, screw on the ring - done. I can't think of a single jar that ever went bad using that method and believe me I have canned hundreds of jars of jams. Now, of course, experts are recommending processing. Since the OP has already found a couple of jars that didn't seal properly after processing, she should simply repeat the procedure with a new lid and making sure the rim of the jar is clean. The processing will take care of any bacterial growth, as long as you process long enough (I might be inclined to add 5 minutes or so to the time just to make sure). A double processing will not, in any way, compromise quality of the jam. It's already cooked.

                  Let's be clear, however, about one thing. I'm talking about jams and jellies - nothing else. These items high in acid and high in sugar - both of which retard the growth of bacteria. For anything else - vegetables, pickles, sauces, etc. - process exactly according to current food safety recommendations. If it doesn't seal, refrigerate and eat as soon as possible. There will be nothing wrong with the food but it can't be trusted to keep without refrigeration.

                  1. re: Nyleve

                    All of these comments are great advice! I'm making tons of Jam and its my first time. Making it as wedding guest gifts. I figured having to do it over and over again would really teach me how to can. lol

                    My QUESTION is about the seals? I know it says you only can use them once but can you reboil them again if you don't use them to seal? For example, I haven't been sure how many jars to prepare since it's my first time. So I've been boiling more lids than I need. Is it ok to reboil them since I don't actually use them to seal? Or can they only be boiled once?
                    Thanks for help and any tips are welcome!

                    1. re: cookieyumyum

                      As long as they haven't been used on a jar, you can boil and re-boil. The boiling only sterilizes the lids, maybe softens the rubbery bit a little. But once it cools, it's just the same as before. I never know how many jars I'll be filling so I always boil more parts than I end up using.

                  2. re: Vetter

                    I have reboiled and reprocessed jelly. I'll never do it again. The pectin tightened up so much you could bounce a quarter off of it and it was quite tough.

                    1. re: Candy

                      Re-boiling jelly will do that. Re-processing will not.

                      1. re: Nyleve

                        I know that. It was the suggestion of some.

                      1. re: toodie jane

                        When you turn the jars upside down there's the possibility that some of the liquid might seep between the lid and the top of the jar and break the seal.

                        1. re: toodie jane

                          I don't trust it, and don't do it myself. because I was taught to seal jars in a water bath -- but French manufacturers of jars, lids, and pectins recommend the flipping method regularly....and everybody I know makes their own jam.

                  3. Thank you everyone for your many suggestions and words of expertise; I so appreciate it as I just made strawberry jam and one of the 60 jars did not seal. I feel quite successful and will simply store the one jar in the refrigerator and not worry about it as I am sure it will be gone in 2 or 3 days anyway. Next year I will know exactly what to do and what not to do thanks to all of you. Enjoy summer 2008! Thanks again!

                    2 Replies
                    1. re: Ellfy

                      ok i have a problem i was jaring some bananna peppers and my jar didnt seal how would i go about that do i re-do everything or can i bowl the jar in water to make it seal again

                      1. re: ccm22082

                        See this post above regarding reprocessing and why you should use new jars and new lids.