Question on if this mold made it into my fermenter

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Nov 17, 2023
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Hello, I recently started brewing a Belgian Tripel and quickly realized the krausen or foam at the top of the fermenter was going to spill over my carboy. So I quickly went out and got a blow off tube, filled a bucket with water and starsan and taped the end of the blowoff tube to the bottom of the starsan filled bucket. I'm not sure how long I'm supposed to use the blow off tube as after 2 weeks of fermenting it is still bubbling, but the top of the bucket has produced what I think is mold. I switched out the blow off tube for a standard airlock, but could this mold make its way into my beer? When taking off the blow off tube the fermenter smelled fine (no scent of mold or infection). I can't really tell if there is any mold at the top of the fermenter because of the thick krausen foam. Any insight would be appreciated. I added some images to show what happened.


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I think it's very unlikely that anything could get from the blow off bucket into your fermenter, especially given the length of the tube. I'd say proceed patiently and just watch for any signs of an issue. If there are none, enjoy your beer!🍻
I agree that it's unlikely anything went back into your FV via the blow off tube, especially if it's been bubbling the whole time. But if you had enough blow off to dilute out the sanitizing ability of the starsan and feed those mold colonies then you're wasting beer. Try a little more headspace next time.
I keep my blow off tubes just below the surface level of the liquid in the bubbler jar. That way if there is suck back, they won't be able to suck that liquid all the way back to the FV.

If you don't see mold growing in the FV, then you don't have mold in the FV. At least not enough to worry about.

The other clue that it isn't in the FV is that there isn't any that I see in the blow off tube. So it's just that you didn't change the gunky liquid in the bubbler jar. Which you probably should do when the FV foams over into it.