Blow-off tube 101???

Incident #3: So I'm reading a crappy little book-- you know the type; 54 pager with platitudes like 'beer originated in Mesopotania but now, you too can enjoy this proud tradition in your home!'-- the type of book whose only purpose for existence is so that sellers can claim that their beginner kits come with a *!FREE BOOK!*. The book says:


Okay... this sort of implies that the blow-off tube has some sort of magic vacuum cleaner power that will magically attract krausen out the tube. Or maybe krausen innately has strong wunderlust that when it sees a wide blowoff tube with its little krausen eye-balls and think in its little krausen brain "At last! And escape route!" and it will plunge its little krausen body to escape the nasty brew it's reluctantly called home all its life.

Incident #0: I don't use airlocks. I have a few 2-gallon lbks (little brown kegs) that I use for fermenters which have a vented lip system. Hence whenever I read about counting airlock bubbles and excessive blow-off tube activity I keep a general "yeah, I understand the theory of what it is but it doesn't really apply to me so I won't concern myself too much about it".

Incident #1: So one day I decide I want to brew a one gallon batch so I figure "Gee, I need something to ferment it in" so I come across a 1-gallon Carlo Rossi wine jug and think "Oho, that'll do, but now I need to figure out this airlock jazz." Well the instructions say put a blow-off tube on it for the first three days and then replace it with an airlock.

Well, monkey read; monkey do. I figure okay, there's probably a lot of forceful activity in the first few days and it might be too much for a fragile little airlock so a big-ol' industrial strength blow-off tube is an insurance precaution.

Incident #2: So I go to my local brew shop and show them my wine jug and say "I guess I need you to hook my up with a blow-off tube". I'm hoping the word "guess" will be the signal to them that I don't know what the eff I'm talking about and will trigger them to go into zen-master teacher mode and reveal the secrets of the mysteries of blow-off tubes to eager absorbtive me. But no, he just cuts me off a bit of 5/16 (or was it 7/16?) tube.

But then he tells me to attach it to the base of a three-piece airlock. (I've never heard of any-one doing this before or since). That way it and the airlock have the same simple base attachment to go into the small hole in carboy stopper.

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Okay... But wait a minute! If the purpose of a blow-of tube is allow for krausen over-flow and excessive force and blockage, isn't an airlock wide opening attachment too small for it?

So help clarify the mystery of blow-off tubes for me

1. What is the purpose of a blow-off tube and how do you use one?

2. Krausen gets into a blow-off tube. Is this a) good; you want krausen in the tube; the tube was designed with magic magnets to attract krausen b) okay; you *don't* want krausen to be that active but if it is, that's what the blow-off tube was designed to handle; or c) aw, man! I hate when that happens. You're screwed, dude!

3. If an airlock is fragile and a blow-off tube is robust shouldn't they have different sized attachments.

4. If the purpose of a blow-off tube is to remove krausen (I don't believe it) then how does it work? Am I supposed to shove the tube way down the neck of the carboy? Will it work if it's attached to the outside of the carboy stopper?

Thanks. This is a very minor and non-critical issue but I don't like being ill/mis-informed.

1. Blowoff will provide a bigger opening for the air to escape. along with the air, will be krausen (possibly, if its vigoroous). Bigger area allows the krausen/trub to leave when it most likely won't fit thru an S lock or 3-piece lock.

2. Yes Krausen will go in the tube. This is normal. I have one tube I use just for blowoffs cuz all the excess gunk from multiple uses has turned it a slightly brown/yellowish color. Even with a heavy duty bath in PBW, it still has a slight discoloration.

3. Depending on the size of the fermentor, (ie better bottle, glass carboy, one gallon carboy, ferm bucket) they will have different stoppers. Some carboys don't even need a stopper if the tube is large enough. Watch the Northern Brewer video on basic brewing and you'll see what I mean. its got like an inch and a half inside diameter. Others, like the one that fits on the inside of the 3 piece lock is smaller. Which is better? I say bigger the better since the larger the ID of the tube, the less likely excessive krausen will block it up. I've only ever used a rubber bung with a 7/16 tube and it has gotten dirty inside but never blocked up completely. The highest OG brew i've made was a Dubbel around 1.068. Thats not to say a barleywine, IIPA or RIS with a much higher OG can't clog it, i just haven't run into that yet.

4. It works by just allowing more of an "out" direction for the stuff coming from the carboy. majority of that is CO2 from the ferment but it can also include the krausen. It doens't have to be deep down in the carboy and def shouldn't go into the wort. I usually have mine about 1/4 past the bottom of the stopper, if its not flush completely with the bottom of it. And yes it will work if its connected to the outside of the carboy stopper as long as it is an airtight fit.

One final thing... The more u troll around here, the more u'll see that not all LHBS employees are sources of vast home brew knowledge. I've read some horrible advice that was given on here to noobs so just keep that in mind. If you have a question, post here or run a search on it and see what alot of the people here say. If it then clashes with what ur told in the LHBS, put what they say into question. Given what u said about the tubing, im not saying the guy u talked to at urs isn't smart or knowledgeable, he may have just not been in a very people person mood or might not be very open with offering advice. Next time u need something, just come out and ask him his opinion on something and see what he says.

Well, to be fair to my LHBS shop-person (who seems pretty dang knowledgeable) I had also bought in the same trip immediately earlier a No. 6 stopper for the corboy/jug and then said "I guess I'll need you to hook me up with a blow-off tube" and thus he was probably hooking me up with a blow-off tube *to use with the number 6 stopper*.

Which really kind of leads to the "use a blow-off tube for three days and then replace with an airlock" of the instructions. I guess I should question them. The brew itself certainly didn't need a blow-off; the fermation was gentle. (But if it had...)

Also, I suppose the problem isn't that an S-neck airlock opening is too narrow. It's that if you get krausen in it, it's screwed; you'll never get it out. (But then again you just buy another; they're $1.50 each...)

Does every-one use both a blow-off and airlock? At the same time?

Ive' given up on S style airlocks because they are very narrow but also are a pain in the ass to clean. I like the rubber bung that i use cuz the tubing fits perfectly and haven't had a problem. I have one 6 gallon better bottle and two fives so if i'm using the six i'll normally just use the three piece. if im using the 5 i'll use the blowoff just to be safe since there isn't as much head space.

Depending on what u have and use and the type of brew u have fermenting, that should help u figure out what u wanna use. I always say go on the side of caution, theres enough horror stories on here and youtube with blown lids/airlocks.

Some that use the 3 peice airlock will put a 1/2" tube ofer the center part into a jug of water & starsan. Others that use carboys just use a big tube to cram in the top of it. I use a 3/8" tube with an airlock stem I cut off an old "S" type airlock to make it fit the airlock grommet in my plastic fermenter lids. Then into a plastic 1/2G vodka jug 1/3 full of water with a splash of starsan. I use it till initial fermentation is over if it's blowing off. If it doesn't need it,or it's done blowing off,I replace it with an airlock filled with cheap vodka. Anything that gets through the airlock cap dies of alcohol poisoning in the vodka.

The only thing "S" type airlocks are good for is if using a secondary where little to no activity happens. They clog to easily.

Gary

To ... er... illustrate what my LHBS guy told me:

This is my blow-off tube:


The tube is attached the the bottom part of the 3-piece airlock.



(The cupping lip is rendered useless; this little base simply serves as a joiner tube between the blow-off tube and the relatively narrow opening of the number 6 stopper.)




The idea is that after 3 days I replace the blow-off tube and its airlock base with an airlock (and its airlock base).





Any-one else use this system? It just seems kind of ... crude ...

I use that system all the time. Nothing crude about it. As a matter of fact I have a blowoff tube on a Hefe right now that is exactly like your pictures. 1/2" hose and the bottom part of 3 piece airlock.

Gary

>>>"Depending on what u have and use and the type of brew u have fermenting, that should help u figure out what u wanna use. "

For now, it's just for the rare 1-gallon batches. Seems kind of over-kill.

"type of brew u have fermenting": you mean whether its a brew with high fermentation activity? Which brews ferment more actively than others? I use a rather high percentage of yeast because I usually buy for five gallons and use half or all of it.

GASoline71 said:

I use that system all the time. Nothing crude about it. As a matter of fact I have a blowoff tube on a Hefe right now that is exactly like your pictures. 1/2" hose and the bottom part of 3 piece airlock.

Gary

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Do you switch it out to an airlock after three days?

Cool, thanks. (This vindicates my LHBS guy who I really kind of think is probably really smart. He's given me great advice and he's *really* friendly.)

Back to my crappy little book... did I misread it or did it imply a blow-off has some magical krausen extracting properties?

I see no problem with that. See my setup and attached pic. Works all the time. No clogs.

i have the same setup, but rarely use it cuz i have the bung. I did take a dremel to the X on the bottom of it though, ive read a few people on here do it just to increase the opening a bit.

JonGrafto said:

I see no problem with that. See my setup and attached pic. Works all the time. No clogs.

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Ooh. I notice you fill the cup with sanitizer (at least I assume it's sanitizer). Is that nesc.? A harmless precaution?

This is my setup, only have the tape on the cap because when the nuclear fermentation goes on I don't want the krausen to push it off! Probably wouldn't happen, but better safe than sorry.

woozy said:

Do you switch it out to an airlock after three days?

Cool, thanks. (This vindicates my LHBS guy who I really kind of think is probably really smart. He's given me great advice and he's *really* friendly.)

Back to my crappy little book... did I misread it or did it imply a blow-off has some magical krausen extracting properties?

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Nope... If I ever have to use a blowoff tube... I just leave it until it's ready to go into the keg. It's just a big airlock.

JonGrafto said:

I see no problem with that. See my setup and attached pic. Works all the time. No clogs.

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Why the starsan in the bottom part of the 3-piece with the blowoff tube? Since the tube is connected to the "inside" part of the 3-piece the starsan/water/vodka isn't necessary. It's your gig... just wondering...

Gary

I use the 3 piece airlock converted to a blowoff tube. I've used it twice, as I hardly ever have enough krausen to need it. I ferment in a 6.5 gallon carboy and keep the temp in the low 60s for ales. most of the time I just use an s type airlock, and have never gotten one dirty. the last batch I did, I came in way under my target og, so I boiled 4 pounds of extract in maybe a gallon of water and added it in, so my carboy was much fuller than normal. the blow off tube was used the first 3 days. by then the krausen had fallen, and I switched to the airlock.

as for needing to remove the krausen, there are many sources that say it contains bitter tasting compounds and the beer will taste better if you remove it. I usually just let the krausen fall back in. haven't noticed any bitter flavors that couldn't be attributed to hops or dark malts. I haven't tried doing a side by side comparison of a batch with the krausen removed and without removing it, so it could be possible the beer would taste better.

woozy said:

Do you switch it out to an airlock after three days?

Cool, thanks. (This vindicates my LHBS guy who I really kind of think is probably really smart. He's given me great advice and he's *really* friendly.)

Back to my crappy little book... did I misread it or did it imply a blow-off has some magical krausen extracting properties?

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no magical properties. once krausen forms, it needs someplace to go. if you have too little headspace, it will push up out of whatever is in the bung, airlock or blowoff tube. in this case, blowoff tube is much preferred. it allows it to safely drain into an awaiting container and not make a mess. if there is sufficient space in the fermenter, the krausen won't reach the bung, and it won't matter what is there.

Hogarthe said:

no magical properties. .. if you have too little headspace, it will push up out of whatever is in the bung, ... if there is sufficient space in the fermenter, the krausen won't reach the bung, and it won't matter what is there.

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Granted. But doesn't:


make it sound like the krausen magically senses an airlock and crawls out of it on its own volition? Or am I just misreading this crappy little book?

Also doesn't it sound like it's saying the purpose for an air-lock is to get rid of that nasty toxic krausen rather that to allow a pressure release? Or am I still misreading it?

C'mon toss me a bone. It's a crappy book, right? Huh, huh? Crappy book? Who's with me? Crappy book, right?

No need to add starsan into the airlock. No just did that as an added security measure and peace of mind.

Here's a question for people. How the heck do you remove the tube from the 3-piece air-lock when done. I've tried all kinds of things to get it off, but it seems impossible! It's like a Chinese finger trap.

johnsnownw said:

Here's a question for people. How the heck do you remove the tube from the 3-piece air-lock when done. I've tried all kinds of things to get it off, but it seems impossible! It's like a Chinese finger trap.

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I got the impression you weren't supposed to. Once it's on it's a unit thing and it's supposed to be a blow-off tube with an airlock base forever. The airlock has given it's life for the cause and the tube is serving a life sentence.

Or at least that was the impression I got.

woozy said:

I got the impression you weren't supposed to. Once it's on it's a unit thing and it's supposed to be a blow-off tube with an airlock base forever. The airlock has given it's life for the cause and the tube is serving a life sentence.

Or at least that was the impression I got.

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I actually use a blowoff on the S Type as well as the 3 piece airlock. I run it under hot water and usually can get it off without a problem...lets me clean it pretty good.

doornumber3 said:

I actually use a blowoff on the S Type as well as the 3 piece airlock. I run it under hot water and usually can get it off without a problem...lets me clean it pretty good.

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I've tried that...it just hasn't worked for me. I was hoping there was a trick to it.

johnsnownw said:

I've tried that...it just hasn't worked for me. I was hoping there was a trick to it.

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I usually let it run under hot water for about 1 minute and then twist and it comes off pretty quickly. Definitely takes a little muscle but but usually comes right off

I was just musing as to whether starsan or PBW might soak it loose enough to get it off?

unionrdr said:

I was just musing as to whether starsan or PBW might soak it loose enough to get it off?

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I tried the starsan, but haven't used PBW/OxyClean. Perhaps I'll just have to run it under hot water and try again. It was pretty soft though, the last time I tried. It just seems like as you're trying to pull it off it clamps down tighter the airlock stem. *shrugs* I'll have to try twisting next time.

woozy said:

Granted. But doesn't:

"In the bucket-type primary fermenter, the krausen cannot escape .. The only way to get rid of it is to open the fermenter and scoop up the brownish foam with a sanitized spoon... The blow-by gets around this problem by allowing much of the krausen to escape the fermenter through the plastic tube."


make it sound like the krausen magically senses an airlock and crawls out of it on its own volition? Or am I just misreading this crappy little book?

Also doesn't it sound like it's saying the purpose for an air-lock is to get rid of that nasty toxic krausen rather that to allow a pressure release? Or am I still misreading it?

C'mon toss me a bone. It's a crappy book, right? Huh, huh? Crappy book? Who's with me? Crappy book, right?

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I'll throw you a bone. That is one crappy little book!

When I put my hose on the airlock, I don't push it down all the way so when it comes time to take it off, I run it under hot water and then push it down all the rest of the way. The water that is in the airlock acts as lubricant and allows me to pull of the blowoff hose.