Fermenting the vegetables in 2,5L glases I always face the problem that the vegetables soak up a lot of water and then dispense a lot and then towards the end soak up even more. The problem is, that the airlocks get soaked out when the volume in the glass diminishes. They are just too short. I use the standard one.

I consider airlock as important. What I did so far is to wait 2-3 days until I fill in the water in the airlocks, but it didn't help a lot. Often the airlock breaks and it soaks in the water from it.

I wonder, whether there is a point in time, when it can't happen anymore, or anything else to know about the stages of fermentation?

1 Answer 1


Use an S-shaped (aka one piece) airlock instead. Harder to clean, but doesn’t siphon out at negative pressure.

s-shaped airlock

  • 1
    That easy, awesome! Did you notice any point in time when it starts to only flow out?
    – Sebastian
    May 7, 2023 at 15:02
  • Changing temperature can always set up a pressure differential; the larger the headspace, the more air moving in/out. Airlocks in lactofermentation are more about keeping oxygen levels down than keeping things sterilised, so it doesn’t much matter.
    – Sneftel
    May 7, 2023 at 15:31
  • Hm. I had much too less overhead space and kept it in a styroporbox that is digitally heat controlled. I doubt it's changing temperature. What I read is that vegetables in the brian release water due to the salt content and that there are different stages, just not sure sure about when they soak up.
    – Sebastian
    May 7, 2023 at 16:54
  • What came to my mind as well, is that this type of airlock isn't a rel air-lock as it lets in air. I would think of the type of air-lock that I am using currently but with a longer pipe, so that it can balance out fluctuations without letting in air. The point is, everyone uses this type without a problem apparently and there are even manufactures who sell fermentation vessels with these air-locks. There must be a way how they keep locked. Any idea?
    – Sebastian
    May 14, 2023 at 10:41
  • I think you might not realize exactly what an airlock does for lactic fermentation. The goal is not to keep the contents under vacuum, but to keep the oxygen level down by limiting air circulation. It’s not a problem if a bit of air gets in at some point— after all, plenty got in when you started.
    – Sneftel
    May 14, 2023 at 11:23

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