When do you need a blow off tube

I have been using a 7.9 gallon bucket to ferment five gallon brews. I have always used the standard three piece airlock with good results.

As i move to new recipes and yeasts, is there a rule of thumb to know when the fermentation will be aggressive enough to require a blow off tube?

With that large of a bucket, you may never need one........ I typically brew 5.25-5.5 gal in a 6.5 bucket and my personal rule of thumb is anything over 1.050 OG.

Depends on the gravity, fermentation temp, and yeast strain. I've never needed one with my 8 gallon bucket, but use one all the time with carboys.

It comes down to how much head space you have in your vessel, if you have 30% or more available then most likely a blow off tube is not necessary but iMO it is a good idea to just get in the habit of using one so you don't ever have to worry about it!

When you have krausen coming out of the airlock That's when you need a blowoff hose

mobilecabinworks said:

When you have krausen coming out of the airlock That's when you need a blowoff hose

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I went to one when I had to clean the krausen off the ceiling.

Just know that your blowoff tube can still blow off like mine did! It needs to allow some good flow...

mobilecabinworks said:

When you have krausen coming out of the airlock That's when you need a blowoff hose

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Mom always said there would be one in every group!

Personally I lways use a blowoff. To me, it's not worth the risk of having to clean up an entire closet, or wherever you choose to ferment.

Its certainly more of an issue the warmer your fermentation area is so its a bigger threat in summer.

I got lazy and didn't use one...turns out I needed it....you can see it was seeping under the Gamma Lid seal

EDIT: This is an Alt at 60F

I have only needed a blowoff tube using a german and belgian true top cropping yeast, especially wyeast Weheinstephan yeast

Lol i thought 5 gallons in a 6.5 bucket would be safe from needing a blow off tube. I was wrong on this beer. Problem is the tube i have is to narrow to handle the pressure so i just have to leave it off with a star San towel on top now.

mistermateo said:

I have only needed a blowoff tube using a german and belgian true top cropping yeast, especially wyeast Weheinstephan yeast

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Those yeasties are little beasties.. they are hungreh.

Thanks everyone

I am pitching white labs kolsch into a 1.05 today. Would you consider this a combination to be concerned about?

It sounds like i should make a blow off tube standard practice in the future.

I've seen several posts that suggest it's better to use a blowoff tube during the active fermentation (usually ~1 week) just in case. Doesnt seem like a bad practice from my experiences.

501irishred said:

Mom always said there would be one in every group!

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Guilty

I always use a 1.5" blow off tube in my carboy. Airlock is only for secondary.

I haven't done many big beers but that one i put the pick of is a 1080 and it's the first time I've needed one. now that is 48 hours into it the blow off isn't needed anymore so i switched to an air lock for space conservation.

That beer next to it is a 1055 and both brewed the same time it's been rocking the air lock hard but nothing like that big beer next to it. I don't see any need of a blow off on smaller beer with at least a 20% head space.

I never used a blow off tube because I have a 30L fermenter and the maxmium I brew is ~23L. that's decent headspace there.

There was once, quite recently, I'm fermenting a weizenbock of OG 1.080. I used freshly harvested yeast from a previous batch I bottled the same day. Overnight, I get good beer flying out of the fermenter.

I can't upload the pictures from the android app as it keeps crashing. I'll upload them when I can.

Edit: It appears that it uploaded them after all.

For me, I've really only needed one for big beers, and in particular when primary fermentation vessel is a carboy. It's why I've gone back to preferring the bucket for fermentation.

my rule of thumb is to always use a blow off for a few days. then airlock it. you could probably get away with just an airlock if its a belgian but even that's risky. you will definitely need it for a hefe or an ipa

You will need a blowoff tube when you don't have one installed.

I feel it is better safe than sorry. The blowoff is almost as easy to set up as an airlock and sure beats cleaning krausen off the ceiling.

Start every fermentation with a blow off tube installed and it will save you the cleanup.

Whenever I use Wy3787. I've never not had it produce a 1.5+ gallon krausen.

I always use a blowoff tube for the first week of fermentation just in case. It's better to be safe than sorry.