I know that not seeing bubbles in my airlock isn’t unusual … which is why their appearance w/a recent IPA is. I’m still a 5-gallon-plastic bucket brewer, so the lid seal is far from perfect. The first half-dozen beers I’ve brewed have been bubble-free in the airlock - like, nothing - but all have turned out fine so far. Most of those were extract-only but I began brewing with partial extracts last summer. Three batches since then - no bubbles. So imagine my surprise when I went down to the basement to check on this latest IPA. The airlock was full of krausen, which had spilled over atop the lid and a bit down the side. This was 12 days into primary. Floor/bucket: 63º. Sampled w/a sanitized baster, SG 1.010. Tossed in my dry hops; assume all is ok. I did notice a slight off odor - can’t really describe - but it tastes fine. The weird thing is that I made this exact recipe last summer w/o an airlock bubble in sight. Only difference: the basement floor was warmer - 70º. I used the same yeast: Imperial Yeast A07 Flagship (liquid, 200 billion count). Any idea what could have caused this surprising reaction? Also: I’ll take another sample in a few days to see if fermentation is done but in the meantime, should I clean out that airlock or just leave it be until I’m cleaning everything?
I’d clean the airlock (or replace with a clean one).
It’s impossible to guess what may have changed on this batch for you. Maybe the fates alligined and you got the lid on “just right” to get a perfect seal.
Pauo
I suspect that this beer had a higher gravity than your earlier batches? That would be one possible cause. I suggest replacing the air lock and wiping things down with sanitized paper towels. The vigorous ferment will likely help you out a bit in terms of avoiding contamination through the airlock.
Had you checked the situation on the days prior? I am simply wondering if the onset of the problem occurred earlier than day 12…
I’m wondering if there was some sort of infection. First, plastic buckets are notorious for getting surface scratches and surface scratches are where bacteria will hide. Also, with a bad seal on the bucket, it is very possible that air actually entered the bucket at the end of the fermentation after all the CO2 was exhausted and the temperature of the beer naturally cooled allowing the dead space in the bucket to turn negative.
I’m wondering if this could also be the cause of the “off odor” you mentioned?
The airlock not only keeps out unwanted stuff, it also serves as a visual aid telling you how things are going in a place you can’t see - inside the bucket.
ynotbrusum: Actually, it was a tad lower - 1.059 this batch and 1.066 last summer’s. Re the onset: Based on my previous no-bubble experience, I figured I had a nice basement temp for fermentation so I honestly just let it be. FWIW, all spillage had dried. I have a spare airlock and will sanitize and stick it in there.
KellerBrauer: Me too. So far, my sanitation process has been solid. At this point, I’ll let it finish and get a couple of friends to taste-test w/me before I bottle - if I do.
Slowbrew: Always possible! 
Now that I think of it, it was harder than usual to get the lid off.
I used to have problems with kausen filling the airlock when i used a bucket to ferment in. As a matter of fact, I still do when using a carboy for a 5 gallon batch.
That said, if the beer has an off flavor, replace the bucket and use a blowoff tube instead of an airlock during the vigorous portion of the fermentation. You should be able to use a piece of a plastic racking cane that is the same diameter as the airlock (that is what I did) and some brewing hose to run the krausen off into a jar with sanitizer in it. That always works for me and eliminates the mess.
Good luck and hope the beer turns out OK.
We’ll see how it turns out, Goose. Thanks for the idea.
You said the only difference was the basement floor was warmer. I believe that is your answer. Temperature will directly impact yeast metabolic rate.
Read it again. He said that for the batch that didn’t bubble over the floor was warmer.
So, if it was dried overflow, it likely occurred much earlier in the fermentation period and the issue of infection was likely not the culprit (though still possible, since the airlock was blown through and may have allowed ambient air through at that point - so likely not infected initially, but possibly infected once the blow through occurred). That is my best WAG and I think you will simply need to see how it turns out. It may be a wonderful beer, after all. Good Luck and Cheers!
ynotbrusum: Actually, it was a tad lower - 1.059 this batch and 1.066 last summer’s. Re the onset: Based on my previous no-bubble experience, I figured I had a nice basement temp for fermentation so I honestly just let it be. FWIW, all spillage had dried. I have a spare airlock and will sanitize and stick it in there.
KellerBrauer: Me too. So far, my sanitation process has been solid. At this point, I’ll let it finish and get a couple of friends to taste-test w/me before I bottle - if I do.
Slowbrew: Always possible! Now that I think of it, it was harder than usual to get the lid off.
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So, if it was dried overflow, it likely occurred much earlier in the fermentation period and the issue of infection was likely not the culprit (though still possible, since the airlock was blown through and may have allowed ambient air through at that point - so likely not infected initially, but possibly infected once the blow through occurred). That is my best WAG and I think you will simply need to see how it turns out. It may be a wonderful beer, after all. Good Luck and Cheers!
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Thanks, ynotbrusum. I’ll post next weekend after my dry hop stage is complete & I pop that lid again. Fingers crossed!
It happens.
Why so much krausen? Could be several reasons.
Why it came through the airlock? Path of least resistance. The thicker foam likely overwhelmed any small lid gaps and went out through the larger exit hole at the airlock.
When it happens just clean up the exterior and the airlock (or replace it).
If it happens often or you fill the bucket with wort more than usual reducing head space, use a blow off tube.
Infection? Doubt it. No reason to even suspect one at this point.