Blow off from Gas in post

[brewzombie]

Anyone ferment in cornies with a blow off tube attached to a disconnect to the gas in post? Seems elegant but ocurred to me the poppet/post/disconnect could clog. I like the idea because I could just swap it out with a CO2 line with disconnect for pressure transfer without opening the fermenter. Would this work?

 

[Ted75]

I've done it and removed the poppet to eliminate the risk of clogging. I think that's how most people do it to be on the safe side.

 

[wilserbrewer]

Hops can and will clog a small dia. blow off. I would try and eliminate hop particles in the fermenter if trying this.

 

[brewzombie]

Thanks you two. So, unless I can be confident there's no serious hop chunks or other particles in the trub, then remove the poppet. I guess I can put it back after fermentation slows down and any O2 introduced at that point will be scrubbed by fermentation. Then I can swap blow off tube with CO2 for pressure transfer. I may start using hops in a fine mesh bag anyway, then hopefully I can keep it in. Cheers.

 

[wilserbrewer]

I would remove the poppet regardless.

 

[beersk]

When fermenting in a keg, I bend the liquid dip tube so it sits about 2 inches off the bottom, and do everything I can to keep hop trub out of the fermenter. You shouldn't have a problem with the gas blow off clogging unless you're fermenting 5 gallons of Belgian blond in there. The krausen will clog it up (ask me how I know this).

 

[agrazela]

Assuming 5gal corny...what size batch?

I'd think if you were doing something like 3-3.5gal batch size, there'd be little likelihood of the krausen ever reaching the gas in tube. Especially if you cut the gas in tube down as short as you can. Then it's basically just an airlock.

 

[brewzombie]

Assuming 5gal corny...what size batch?

I'd think if you were doing something like 3-3.5gal batch size, there'd be little likelihood of the krausen ever reaching the gas in tube. Especially if you cut the gas in tube down as short as you can. Then it's basically just an airlock.

I was actually thinking of fermenting about 11 gal in 15 gal, either a corny or a converted sanke. Same principle should apply, though. Unless the krausen is really high, there should be no problem. I have seen huge krausens though for a WLP300 fermentation of 21L in a 30L Speidel...massive blow off, so it could definitely happen. The question is if the krausen would end up clogging the poppet in such a scenario.

I never thought of shortening the gas diptube so that could help a bit.

I guess the concern with a clogged poppet is it turns into a pressure bomb but I'd think the pressure would force out the clog before breaking steel. Am I wrong?

 

[beersk]

I guess the concern with a clogged poppet is it turns into a pressure bomb but I'd think the pressure would force out the clog before breaking steel. Am I wrong?

You didn't ask me how I knew it'd clog the blow off, but I'll tell you anyway. It's ridiculous. It won't break the steel, no.
I brewed a Belgian blond, about 4 or 4 1/2 gallons in a 5 gallon keg. Blow off clogged, let it be clogged for too long...so...I had to take the post off. Guess what happened when I took the post off? I expected it to maybe just ooze out of the gas post hole. But nope, it took about 2 or 3 seconds, then, BOOM! It f*cking geysered out of there, 6 or 7 feet in the air for about 5 or 10 seconds. I wish I had a video of it! Man, the mess it made...

Don't let it clog. Period.

 

[wilserbrewer]

Yes yes....plus your batch of partially fermented wort is now carbonated to who knows how many volumes...milk shake beer not fun.

 

[brewzombie]

You didn't ask me how I knew it'd clog the blow off, but I'll tell you anyway. It's ridiculous. It won't break the steel, no.
I brewed a Belgian blond, about 4 or 4 1/2 gallons in a 5 gallon keg. Blow off clogged, let it be clogged for too long...so...I had to take the post off. Guess what happened when I took the post off? I expected it to maybe just ooze out of the gas post hole. But nope, it took about 2 or 3 seconds, then, BOOM! It f*cking geysered out of there, 6 or 7 feet in the air for about 5 or 10 seconds. I wish I had a video of it! Man, the mess it made...

Don't let it clog. Period.

Ohh, I get it. Haha. Thanks for sharing this! I won't take any chances. Happy to have learned from your experience.

 

[brewzombie]

Yes yes....plus your batch of partially fermented wort is now carbonated to who knows how many volumes...milk shake beer not fun.

Haha. Good point. Cheers for responding.

 

[beersk]

Yes yes....plus your batch of partially fermented wort is now carbonated to who knows how many volumes...milk shake beer not fun.

I've fermented in kegs a lot and that was the first time it's happened after doing it for a couple years. Just didn't expect it to be that bad. I was sure wrong. The beer turned out pretty good though as frustrating as that was to deal with.