I'm trying to ferment sliced red onions in orange juice with 6% salt. I used one tablespoon kimchi juice to start it.

It was started Monday last week, but until yesterday (after a week), there weren't any signs of fermentation occurring, not even bad smells or mold or anything, but then, yesterday at last I began seeing some small bubbles and today it's going really wild with the bubbling.

It's been a week and I'm afraid it has some bad bacteria producing the bubbles, because of the long time that has passed.

I'm using an airtight jar which I've burped once everyday since the first day, and also mixed the contents everyday to avoid anything being on top for too long.

Is it safe to eat the fermented onions, or should I toss them?


While I know cold weather would slow down the fermentation process, I don't believe that's the case, since where I live, it's been around 68F-75F for the last week.

  • 1
    Weather is still cool. Kimchi will take weeks around here. I'd give your onions and orange juice (!) more time, and smell carefully before testing. Do you know what the good stuff is supposed to smell like? If not, it might be better to wait for summer and better fermentation conditions. Commented Apr 5, 2017 at 1:45
  • 1
    @WayfaringStranger Just because the weather is cool for you doesn't mean that it's like that for everyone... here in central Texas it's been in the upper 80s for weeks.
    – Catija
    Commented Apr 5, 2017 at 3:44
  • @Catija Yeah, I could've phrased that better. Commented Apr 5, 2017 at 3:46
  • 2
    6% is a super high level of salt, I use not more than 3% for whole veggie ferments.
    – thrig
    Commented Apr 5, 2017 at 15:04
  • 1
    Tested kraut with 2, 4 and 8% salt. 2 worked fine. 4 was way too salty and somewhat slow. 8 got moldy rather than fermenting. 6% is WAY too much salt...
    – Ecnerwal
    Commented Apr 5, 2017 at 23:40

1 Answer 1


Edit: See my question here. I plan to update this answer after I get an answer to that question.

I'm a beginner when it comes to this (I've fermented a few quarts of pickles with Fermilids), but from everything I've read, you'll probably survive if you eat it. However, if you add too much salt, that can kill the bacteria needed to do lacto-fermentation, and you may end up salt-curing your vegetables instead of fermenting them.

From what I understand, a 6% salt brine solution is about 3.34 tablespoons per quart of pickles. I've read that your brine should only ever be between 1 to 3 tablespoons of salt per quart of pickles (if you're not using a starter, and you can perhaps use less salt if you use a starter), and that you should use more salt the warmer it is (but not more than 3 tablespoons).

I believe the delay is partially, if not entirely, due to the salt. I imagine that the activity is from beneficial bacteria that needed a longer time to get started, due to the salt. I don't know of any bad stuff that would survive those conditions, if you're not getting mold. I can't give you a definitive answer here, but from everything I've read, that's my opinion.

I used 2.5 to 3 tablespoons of pickling salt on a quart of rhubarb, and I didn't taste much lactic acid in it after three weeks. However, with about 2 tablespoons of pickling salt, and a probiotic (a chewable L. acidophilus and B. lactis tablet) my rhubarb tasted pickled after 6 days. Temperatures for both sets of pickles were between 69 to 73° F., I believe.

From those results and the results with my radishes, I personally would be leery about using more than 2 tablespoons of pickling salt for some vegetables. I'm not sure about cabbage, onions, oranges, etc.

Remember, though: I'm new to this. So, you probably know things I don't.

You'd think onions would ferment quickly, because they're known for their content of FOS (a pre-biotic and sweetener). However, from my experience, I know oranges can take a really long time to compost in a garbage can with a lid on it (they're still whole and visibly oranges after a couple years). So, maybe the orange juice contributed. I'm not sure how LABs respond to citric acid.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.