How do I re-process unsealed strawberry jam?

I made strawberry jam today and canned it in Ball jars via the Blue Chair Jam cookbook method. For any unfamiliar with this method, you sterilize the jars by leaving them in a 250 F oven for 30 minutes, add the hot jam, put on the lids and return the jars to the oven for 15 minutes more. Once removed from the oven, the seals on the jars activate. However, this time I had several jars that didn't seal. Can I reprocess these jars? I only removed them from the oven about 1 1/2 hours ago. I don't want to compromise the safety of the jam by partially cooling, then reheating in the canning process. What do you guys think? Put them back in the oven or leave them as is?



Krislild July 9, 2024
So if u are concerned the jars did not sterlize completly u can reboil jam and steralize jars to ensure safe canning?
jamcook September 29, 2014
Also... With all the sugar in jams and acid from the fruit, and most probably lemon juice, you are not going to get botulism... Maybe mold, maybe sour tasting spoilage, but you are not going to kill anyone. The Ball Blue Book is a good source of information and processing times, and some good basic recipes.. A good jumping off point, then later you can get fancy.
jamcook September 29, 2014
I have also heard that the oven method is not completely safe. that said, my grandmothers did not process at all.. They put the jam in clean jars and sealed them with paraffin. I have never had an unsealed jar using a boiling water bath. I do make extra jam which I don't seal , and put in the fridge for family use and it lasts a long time. You might just want to refrigerate the unsealed jars and use them first.
minibakersupreme June 3, 2013
Thanks! The last time I did it, it worked perfectly, this time I used a few old jars, and those were the ones that didn't seal. Maybe the edges were chipped and I just couldn't see. I like the oven method for my tiny kitchen, where I don't have room for a canning pot. Thanks for your help!
aargersi June 3, 2013
You can re-can but you will need to un-jar the jam and clean the jars, reheat the jam, and use new disc tops to can. Otherwise the safety of the jam on the shelf is compromised. Other wise into the fridge it goes!! I have only used the oven method once and it makes me nervous - I like the sure knowledge of boiling water and quickly popping seals ...
minibakersupreme June 2, 2013
I make jam and keep it for a long time in the fridge, but these were intended for gifts in the future. Change of plans?
dymnyno June 2, 2013
I wouldn't worry about reprocessing the jars. Jam has a lot of sugar which is a great preserver so the jam won't to bad fast. Just heat the jam and start over with clean jars.
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