Like the title says, I opened a jar of locally produced olives and it started to bubble like seltzer. Is it unsafe to eat?

  • Note I made a minor change so that the main question in the title and the main question in the body will both be the same answer. Initially the answer in the title is yes while the answer in the body would be no. I wanted to eliminate that confusion.
    – Jay
    Apr 21, 2016 at 18:25
  • 9
    Can you contact the people who produced them and ask if it's normal behavior? That's probably the easy way to find out and they're more likely to be correct... plus, if it's not normal, they'll likely offer you a replacement jar!
    – Catija
    Apr 21, 2016 at 20:14

4 Answers 4


Short answer:
Yes, throw it away.

Long answer:
Bubbling, fizzing, pressure etc. indicates some kind of microbiological activity that is unwanted for properly canned food - canning should eliminate these organisms. Any behaviour like the one you described indicates that something went wrong, so you can not assume the contents of the jar or can to be safe.

  • 1
    But what about certain canned items such as Kim-chi? Store bought Kim-chi always bubbles/fizzes when I open the jar for the first time.
    – Programmer
    Apr 21, 2016 at 18:47
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    Well, the short answer is that kimchee is fermented, so that's normal. olives are pickled, which is a different thing. Olives shouldn't fizz and bubble!
    – franko
    Apr 21, 2016 at 19:09
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    Yeah, this answer is incomplete in not mentioning that bubbling is completely normal for fermented foods. And, lots of varieties of olives ARE traditionally fermented, not just pickled. Since the OP says they're locally produced (and presumably not mass-produced), it's entirely possible that the producer uses a traditional method of preparing them, and thus they are fermented. Still, without knowing for sure, I wouldn't take the chance.
    – Elezar
    Apr 21, 2016 at 19:25
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    In my experience, pickling can refer to any of several preservation processes that involve vinegar or a similar acid (either as an additive or as a byproduct of fermentation). For example, pickled cucumbers are sometimes fermented and sometimes not, but are always called pickles.
    – Era
    Apr 21, 2016 at 20:07

Not necessarily. It depends of whether it is expected or not. Some curing methods result in this. I was offered such olives once. They were kept in a big pressured plastic soda bottle.

They were delicious, I ate all of them and I was perfectly fine.

The person who gave them to me rightfully warned me to unscrew the cap slowly and vent the pressure gradually.

However I would be surprised to see any commercial (supermarket) products prepared in this manner.

You say locally produced, so your best bet is to ask the producer.


My family has preserved olives for years. Yes, perfectly good olives fizz. We preserved ours with salt and a small amount of vinegar, then filled the quart jar with water, covered the olives and allowed to rest for months. This causes fermentation and the olives will fizz. I have also had this happen with green olives I preserved in a brine (no vinegar), and this causes olives to fizz as green olives are also acidic. They are delicious and perfectly edible. Locally preserved olives are most likely fermented, but to be safe check with the producer.


Yes, the olives should be thrown out. They might look good and smell good but taste bad.

  • 2
    I neglected to mention on your other answer: please be sure to write clearly and be respectful. Another kind user has helped you out with that, but your answers will be better received if you do it yourself!
    – Cascabel
    Apr 21, 2016 at 22:55

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