Canning 101: Is Condensation Inside Sealed Jars Safe?

plum jam

Like so many Canning 101 posts that have come before, this week’s post is prompted by a handful of emailed questions I’ve gotten recently. People have been writing to ask about the condensation droplets on the undersides of their mason jar lids. Is it safe, they wonder?

It is entirely normal to have a few drops of moisture on the underside of freshly processed mason jar lids. You experience condensation when warm, moist air is cooled. The cooling air doesn’t have the same capacity for water vapor as the warm air, so the water transforms back into its liquid state. It just makes sense to see some drops of liquid inside the jar.

It is not a sign that your jars are spoiling or that some water from the canning pot leaked into the finished product. Typically, the condensation will eventually reintegrate into the product. If it doesn’t, it’s still not a sign that it is spoiling. As long as the seal is still good and the product doesn’t look significantly altered, all is well.

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16 responses to “Canning 101: Is Condensation Inside Sealed Jars Safe?”

  1. Thanks so much for the timely post! I canned beets over the weekend and there was some condensation and I was wondering if there was an issue! My cans are sealed and have no leaks! This makes me feel much better! Love your blog! Thanks!

  2. I just wanted to tell you that I love your Canning 101 posts (and the rest of them, really)! I got into canning a few months ago, and your blog is an excellent resource for all those little things no one remembers to tell a beginner. Your books are both on my Amazon wish list for the holidays!

  3. Can you tell me why when I think my soup has sealed bcz of indentation of lids a few days later you hear the ping and it is not sealed at all?? Is the food that has set there for a couple days with the lid indented good? I have been trying to can vegetable beef soup as well as chili. Please could you send an answer to my email please??

    Thank you so much and God Bless you.


    • Rita, are you pressure canning your soup? Because that’s the only safe way to preserve low acid foods like soup and chili. If the jars are unsealing, then you’ve not processed the jars correctly. I’d suggest you contact your local extension service.

  4. Thank you for that I was concerned that the condensation was a sign that it had not sealed properly even though the lids are secure.

  5. Is botulism a big concern with habenero pepper jelly. I followed all the steps and my jars are sealed but this is my first time and I’m worried. Please email me.

  6. I just made peach jam with just peaches and sugar. I opened one jar today (2 days later) and it took some effort to remove the seal. Now it didn’t have a loud popping sound when I removed it – not sure If it has to. I found some moisture under the lid – water droplets. how much water is ok? I did them with my mom and followed her method of canning which is placing the hot jam into very hot jars from oven. Seal and leave. I am concerned that the jam will go bad, if not already.

    • It doesn’t have to make a loud sound when the lid is removed. And while your mom’s sealing method isn’t the one most often recommended, it is effective in producing a seal. If your jars spoil, you will be able to see or smell the spoilage immediately. If you don’t see signs of mold or the bubbling of fermentation activity, it is fine.

    • It’s very unusual for water to leak into jars from the canning pot into mason jars. But if it does happen, you need to discard the contents of the jars.

  7. Hello and thank you for the time you take to share all this expertise. I have searched for an answer to my question and not found one yet. I canned several jars of super hot roasted tomatoes and they sealed well. However, a few of them are only half full. Is that a problem? I wonder if all that air at the top of the jar could cause spoilage. Thanks again.

    • Did they lose liquid during processing or did you can them half full? If they were full to start and lost liquid during the water bath process, they should be okay. If you started them half full, they might have spoilage issues going forward.

  8. Thank you Marisa,
    I canned them half full – there wasn’t enough to fill a jar to the top. They sealed well. Would you recommend that I open them all and make full jars out of the half ones and then can them?

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