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Air Lock vs. Blow Off

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85 Haro Designs

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So, as I browse through the subject matter I notice that some people are having midnight "explosions" when their airlock becomes clogged with the foam / debris.

I'm about to put my first batch to IPA into my carboy (now demarked nicely with gallon graduation marks on the side, thanks to suggestions from the members) and I was wondering if I should be afraid of my airlock becoming clogged during fermentation?

My carboy is a 6.5 gallon size and I'll be making a 5 gallon batch. Is this enough room to allow for expansion of the foam without clogging the airlock?

Is there one situation where a blow-off is a neccessity?

As always, any and all info is appreciated.

PS - I have my own contracting company so I'd be happy to trade some know-how for know-how. :D
 

Yooper

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Well, I've only ever needed a blow-off tube two or three times. I think there are sometimes when you need them for sure- when you pitch on a yeast cake, when you're making a wheat beer, when the temperature gets really high unexpectedly, or when you are using a fermenter with very little headspace.

I'd start out with the airlock if I thought I had enough headspace, and use the blow-off tube if it's needed. Some brewers just always start out with a blow off tube, though. I'm kind of a klutz and I'm always moving stuff around here, so I like the airlocks since there is less chance I'll spill something. If you have a dedicated place for your fermenters, though, a blowoff tube might be fine. Remember, a blow-off tube really is just a big airlock.
 

chthonik

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We always use a blow off in primary. I KNOW we've needed it for every hefeweizen variant we've made. We usually don't use an airlock until secondary (for beers at least). We use a 6.5 gallon carboy and a bucket. The bucket usually has enough headspace that nothing comes up the blow off tube, but the carboy usually has some evidence of stuff making into the tube at least a little.

Just remember to always clean and sanitize your tube!
 

njnear76

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Blowoff tubes are a good insurance plan. I use one for the first 2-4 days just in case. I highly recommend using one.
 

Joker

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I use the same method as Yooperbrew. I use 6 gallon plus sized vessels and the only time I came close to trouble was a wheat pitched on a yeast cake.
 

abracadabra

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Ask yourself this question. Which is better to use a blowoff tube and not need it or
need a blowoff tube and not use it?

You may also need a blow tube for "big beer" aka high SG wort.
 

JamesKY

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If you have the blow off tube then you may as well use it although you would probably be fine with just the airlock.
 

njnear76

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blacklab said:
i love a good midnight explosion.
Same here. It blows off some of yuck out the carboy. Maybe it's my imagination, but sometimes the beers that blew off taste better.
 

TinmanDan

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In my opinion, if you have room for a blowoff tube, use it. I use a blowoff in my primary fermenter no matter what kind of beer I'm brewing. Airlocks are great for the secondary, once the yeast's job is mostly done. In most cases, the kreusen never approaches the blowoff, but my theory is, why take the chance of an explosion if you don't have to?
 

HP_Lovecraft

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I used to only use airlocks because my cats/dogs would drink out the water in the bowl/bucket for the blowout tube. Or knock the bowl over while involved in some sort of curious mischeif.

However, I've recently started brewing lagers, and I've found whenever I adjust temps (fermenting to diacetly rest, to fermenting, to racking to lagering, etc), the change in pressure will suck in the airlock fluid. I always use vodka, but sometimes it sucks in ALL the fluid.

So I've switched back to blowout tubes for lagers. To avoid the cat/dog problem, I use a 16oz soda bottle (sanitized). The opening is slightly larger then the hose itself. The genius of this system is its impossible to knock over, and otherwise totally problem free.

nick
 

abracadabra

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njnear76 said:
Same here. It blows off some of yuck out the carboy. Maybe it's my imagination, but sometimes the beers that blew off taste better.
Not just your imagination according to John Palmer of "How to Brew" it makes for better tasting beer.

I think it was Palmer it could have been Papazian.
 
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