I successfully canned one batch of roasted red pepper pasta sauce but had to step away from the kitchen for a half hour. When I came back the sauce was still warm so I heated it a bit more while I boiled my next set of jars. Everything looked good going into the water bath canner, but when I started to pull them out sauce started bubbling out of the jars. Did I somehow ruin the sauce by letting it cool then reheat? Can I somehow save it and re-can or should I bag and freeze it. Thanks all.

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    If sauce is coming out of the jars, you likely overfilled. With my pressure cooker, liquid in a sealed jar will continue boiling for up to 30 minutes after I set a jar aside to cool. There's a vacuum in the jar, and water boils in a vacuum. It takes a while for things to cool, and a non-boiling equilibrium to set in. Aug 16, 2019 at 15:26
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    Could also be that it got superheated and started boiling, but I think this unlikely as the sauce most likely has plenty of nucleation points.
    – bob1
    Aug 16, 2019 at 21:55

1 Answer 1


A few questions to consider:

  1. Were you following a recipe that used an additional acid (like citric acid or lemon juice) in addition to tomatoes and peppers?
  2. Does your recipe include significant amounts of garlic or onion?
  3. Does your recipe specifically call for water bath canning?
  4. How many years old is your recipe?

The reason I ask these questions is that most modern-day tomatoes grown for conventional stores do not have the PH levels that our grandmother's tomatoes did, making most canning recipes for tomato sauces unsafe for traditional water-bath canning methods, unless you are adding an acid like lemon juice or citric acid.

Likewise, large amounts of garlic or onion will also affect the PH in a way that makes them less safe for water bath canning.

I tend to agree that your bubbling is likely from over-filling the jars.

To be absolutely sure and on the safe side, boil the sauce from those jars again - bring to a boil, then simmer for 10-12 mins., then can again, leaving approx. 3/4" minimum of headspace at the top of your jars.

I wouldn't recommend leaving the cans as-is that bubbled over, as it indicates the seal is broken or a strong, clean seal was not created in the first place.

Good luck with your canning adventures!

  • Why do you need acid for canning tomato sauces? Jellies and other canned goods aren't particularly acidic.
    – csjacobs24
    Feb 27, 2020 at 21:29

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