I'm making Kimchi for the first time and I have two questions about air bubble removal.

First, all the recipes I've seen say to press the Kimchi down to remove air bubbles. My batch had a few small bubbles lower in the jar, probably the size of a lentil or less, and when I tried pushing down deep enough to get them out, it tended to just introduce more air bubbles around the muddler I was using to press it. Short of putting the jar in a centrifuge, I don't see how I could get these small bubbles out.

How strict should I be about initial air bubble removal? Is it ok to have a few very small bubbles like the one highlighted below?

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Second, I see after the first day that some larger bubbles have formed lower down in the jar. This picture shows a larger bubble after 24 hours of fermentation which was definitely not there when I initially jarred and packed the veggies down:

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Recipes I've seen tell you to push the solid contents down below the surface of the brine periodically as it ferments.

Should I also try to remove new/larger bubbles as they form during fermentation? I.e. by pushing deeper into the jar with a muddler. Or does doing so risk contaminating the environment with new external bacteria?

  • I haven't actually tried this, so I won't put it as an answer, but if you really want to get rid of the bubbles, could you just jostle it lightly (or put it on some kind of agitator...like on top of a washing machine) to bring the bubbles to the surface?
    – Beska
    Commented Jun 18, 2021 at 13:39
  • @Beska The might work, but I'm not sure. The Kimchi is chunks of vegetables that are still relatively intact (e.g. the cabbage is still crunchy), so I don't think they'll shuffle around and let air bubbles slide upward past them the way they'd need to for that to work. Unlike, say, a chunky strawberry jam where I could see that working.
    – SSilk
    Commented Jun 18, 2021 at 21:16
  • 3
    Pressing down in the kimchi is actually a good idea: I do it al the time, and traditional kimchi was made with heavy stones pressing down on the top to remove the air bubbles. That ensures proper fermentation, and fresh-tasting kimchi. The preferred method is to use a clean plastic long glove, and press gently down on the kimchi until majority of the sir bubbles are gone. Commented Jun 19, 2021 at 22:05
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    additionally, make sure next time there's enough space in the top of jar for the kimchi to rise, so you don't have to worry about overflowing!
    – Luciano
    Commented Jun 21, 2021 at 8:52
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    @Beska Following up on your suggestion, I tried jostling and that did nothing. Then I tried tightening the cap on, and lightly pounding the jar's bottom against the counter while keeping it upright. Neither made any of these larger bubbles move visibly. Based on that, I don't think a longer term agitation like the washing machine idea would do anything. I think the issue is the Kimchi is just too thick and with large chunks of vegetables for this to work.
    – SSilk
    Commented Jul 1, 2021 at 21:29

2 Answers 2


Small air bubbles are normal and make no difference to kimchi fermentation, nor do larger bubbles that form during fermentation. As long as the kimchi remains more or less submerged in the liquid, there’s no need to remove the trapped gas. Kimchi is an extremely difficult thing to mess up - once established, the lactic acid bacterial culture will murder any microbes that get in its way - so i think that manually degassing it would probably be okay, but it would serve no purpose.

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    +1. I only "degass" (I actually just push the kimchi down) when it's rising too close to the top of the jar!
    – Luciano
    Commented Jun 18, 2021 at 7:53
  • @Luciano So you're saying you'll degas to stop the Kimchi overflowing the jar, not for any fermentation-specific reasons? That makes sense, and thanks for the good tip. I'm on day two now and there are more and larger air bubbles, and I do see that the top of the brine is getting close to the top of the jar. So I might try to get a few of the larger bubbles out soon.
    – SSilk
    Commented Jun 18, 2021 at 14:39
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    @SSilk yeah I just push the kimchi down if it's close to overflowing (sometimes the batch is too large for my container), never paid any attention to bubbles specifically. Pushing it down will mostly squish the bigger bubbles, and that's usually enough for me.
    – Luciano
    Commented Jun 21, 2021 at 8:51
  • And too much compacting results in chilie settling in bottom. A little wiggle room allows a shake every now and then to disperse solids. Unless one enjoys thicker spicier dregs (I do)
    – Pat Sommer
    Commented Jun 23, 2021 at 5:27

I believe the instructions are about trying to remove any major air gaps, initially.

As the process goes on, and your kimchee is fermenting, it will be impossible to remove bubbles, since the fermentation process that kimchi goes through produces carbon dioxide as a by-product.

Remember, the original, traditional kimchee isn't made in a glass jar and micromanaged. They put the cabbage and other ingredients into huge crocks and bury them in the ground for weeks or months, so, clearly, kimchee can be made without removing bubbles as they form.

  • 2
    That's a good point about the traditional method not involving air bubble removal.
    – SSilk
    Commented Jun 18, 2021 at 14:35

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