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Delayed Sudden Over Flow during fermentation

Need some help from the Brew community. I’m brewing Northy 12 extract with Trappist High gravity yeast. Used a starter so it kicked off in under 12 hours. I was about 72 hours into robust fermentation, Krausen had formed and died back. Fermentation was subsiding. I came home to find my fermentor covered in thick sludgey yeast (not like foam overflow) that came out through the airlock. No noticeable foam beyond about an inch of froth at surface (5 gal in a 6.5 gal big mouth). I cleaned it up, reset everything an was getting a bubble about every 8 sec. Next morning, there was sludge everywhere again, but the fermentation itself seemed calm…very odd. has anyone ever seen this before? Could it be building a bubble at the bottom of the fermentor than “exploding”? Never experienced something like this before


Is the temperature of the beer in the fermentor remaining steady? Is there any possibility the temperature could be increased by a faulty controller. Are you fermenting in a keezer with a heat source?

What are you using for a fermenter?

I’m fermenting at room temperature, so the wort/beer is pretty stable at 70 F

Using a 6.5 Gal Big Mouth for 5 gal batch. Foaming was never observed to be within 3 inches of the bubbler

That’s what I was curious about.must be building up while your away then blowing off. Strange that it didn’t it twice. Just lucky. Next time use a blow off tube

I’ve been brewing for about 4 year and never seen this. Its kind of belching out. What’s weird is that it didn’t happen until fermentation slowed from high Krausen.

Lot of fuel in a Northy…Lower temps might solve the problem(at least next time).

You don’t own a cat, do you? Cat likes huffing the fumes from the fermenter, gets sudden urge to expel hairball… It could happen.


Thats silly cats don’t sniff it dogs on the other hand. Probably kraussen built up clogged the lock then blew it out and then settled down you just missed the show.

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Maybe take a sample, and taste it… High gravity, well, your yeast, or some get going crazy do some quick budding die off, then the young buds mature and starts all over… Class group of yeast… Sneezles61

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Haven’t you ever dry hopped with catnip?

Or made a Bonito Gruit?

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Any thing like our cat, gets too squirrely just getting close to it! Sneezles61

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