I made a kettle sour and added guava in secondary. Everything was going well for a week. I went out of town for the weekend and noticed my carboy stopper and airlock about three feet away on the floor. Beer looks like it may be contaminated... thoughts on what to do?

Could I add some campden drops or reboil? Or is it ruined?

  • Yes. It's happened to most of us at one time or another. Commented Aug 13, 2019 at 22:00
  • I have 4 vessels and only 3 airlocks/stoppers... I purchased a 4th set at a local brewhut but it doesn't seem like it fits as well as the others and I'm afraid it's going to shoot out while I'm not looking. Just waiting to replace it now instead of risking it. Commented Aug 15, 2019 at 19:36
  • @makokstate you can ask a question if you need more information here: homebrew.stackexchange.com/questions/ask you may also research "Blow off tube" that could be useful...
    – Philippe
    Commented Aug 19, 2019 at 18:15

2 Answers 2


It usually happens with strong fermentation when the krausen clogs the airlock, it is then ejected with the pressure.

If the fermentation was still active when you returned, the beer might not be contaminated due to gas escaping the container. What makes you think it is contaminated? Is there anything unusual floating on the surface?

You can always add campden drops, but if a contamination already occur, there is no way to know if it will be enough to salvage the batch.

It could also be fine, I would continue the brewing process, smell and taste the brew from time to time to make sure there are no changes compared to what it is supposed to be.

It happened to me once, a full day without airlock and the batch turned out great. Keep your fingers crossed and hope for the best, but do not drop the batch before trying.

  • Thank you for the reply! I’m not quite sure how many days my brew was open to the air. Up to three days is the worst case scenario. The look of it makes me concerned.
    – Hemclaug
    Commented Aug 13, 2019 at 21:56
  • Unable to add a photo. Essentially it looks like white yeast bubbles or mold without fuzzies.
    – Hemclaug
    Commented Aug 13, 2019 at 22:03
  • That does sound like a wild organism pellicle (contamination).
    – dmtaylor
    Commented Oct 8, 2019 at 11:21

Guava will do that. My first guava ferment went so much harder than that. A couple of days before leaving on a two week trip (with very little pre-planning due the reason for the trip) i had started a carboy full of guava mash. The night before departure the airlock clogged with foam and sometime around two a.m. the house boomed and i thought a handgun had gone off in the other room. The roof, walls and door of our mud room were painted with guava mash, and our departure for the airport was too close to even clean up. It took serious scrubbing when we got back. SO yeah, guava will do that. But it also makes a real fine melomel.

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