Blowoff Tube for Corny Keg Fermenter

[Brushwood Brewing]

I've been looking at a number of articles and videos about fermenting in corny kegs. It seems like a good option (other than not getting a full 5gal batch). Many of them (including Brian at Short Circuited Brewers) recommend using a 1/2 inch silicone tube in place of the PRV as a blowoff tube. Why not just attach a QD to the gas post and run a line from there? Is it more likely to clog a poppet that way? It would seem to be the simpler solution, and could more easily ensure no oxygen enters the fermenter when removing it.

 

[day_trippr]

Do you feel lucky?

The idea of using the PRV port provides a much bigger bore allowing krausen 'n' stuff to pass than possible with a post plus QD, either of which would be far more prone to plugging up than the big hole in the lid...

Cheers!

 

[tracer bullet]

I can't see any reason why not do it that way. I haven't done it this way but it was my plan if I get around to it. I've certainly seen examples of it.

If you are looking at it from an O2 standpoint, keep in mind to try a line like EVA barrier or even stainless or something to keep O2 out of that as well. Or you'll undo some of your achievements.

 

[beersk]

I've always used a QD with tubing into a jar of sanitizer, have had blow off, never have had it completely clog, although there were times that I wondered if it would. Always turned out just fine. Now I ferment 3.5 gallons in kegs with a spunding valve. It's awesome.

 

[BongoYodeler]

Limited experience here, but on both my corny keg fermentations I've used the gas QD for passing gas (CO2!!). The first time it was into two additional kegs, the first containing dry hops, then on to the serving keg, and out to a container of diluted Star San.. My second time keg fermenting I just attached it to the serving keg with a spunding valve on the gas port of the second keg.

First time no issues. Second time a small amount of krausen may have been pushed to the serving keg.

 

[grampamark]

I’ve fermented in, and served from, the keg exactly twice just to experiment with the process. I removed the poppet from the gas post and used a piece of 3/4” tubing for a blowoff. Neither batch was hoppy (a Blonde and a Dunkelweizen) and I had no problem with clogging. In both cases the Starsan in the blowoff container remained clear. I put 4.5 gal into the fermenter so had about a gallon of headspace. After pushing the trub out (about 3-4 pints) I got 4 gal of clear beer.

 

[ebbelwoi]

I attach beer line to a gas QD and run it into sanitizer, with no modifications. I do use Fermcap-S, and I take care not to fill the keg to the top.

I've never had krausen get into the line, even when fermenting Weizens.

 

[Brushwood Brewing]

Thanks all. It's helpful to hear your experiences. I will probably go through the gas QD then, so I can easily use the CO2 to purge the serving keg.

 

[odie]

I keg ferment all the time. I have 5 going right now.

I put a full 5 gallons in each keg. I don't have issues with blowout and I don't use campden or anything.

The one exception is Hefe. It will blow out krausen. But not any beer. So use a bigger bucket.

Lagers will get a spunding valve immediately on the gas post, set to around 10 psi. No issues with krausen pushing out the valve. after a while It gets pulled and will finish carbing up to target psi.

Ales I will either use a QD and tube on the gas post, into a jar of water, sometimes a little krausen, sometimes nothing. never a clog. once is slows considerably I will just remove the QD and let it carb up at the ending of fermentation.

Ales , I will also remove the gas post and use a 1/2" silicone tube into a jar of water. once it slows I will remove the tube and replace the post and let it carb up as it finishes.

In ALL cases, I have replaced the original "grey" PRV with a "red" PRV. The grey ones pop around 90psi. The red ones are around 25psi. At room/fermentation temps, 25 psi is around the target carbonation point for most beers. So I can basically forget about it and the beer will finish close to the desired carbonation level.

When you chill and tap it, your regulator will either add a little to finish carbing it or you will have a few pints to increase headspace to bleed off any over carbonation.

You can use the "blue" 15psi or "purple" 10psi PRVs if you want even lower psi set points. But it's an "approximate" or "average" psi. they may pop a little higher and reset a little lower.

 

[RichB1]

I start fermentation in a bucket and when it gets to about 1.030 (right after high krausen), I transfer to keg to finish fermentation. At some point I will take the hit on the cost of a Tilt to aid this process. Then I run a gas to gas line to serving keg filled with starsan, and serving keg liquid out hose to bucket. when serving keg is empty (sitting on a scale), I then attach spunding valve to ferm keg in the hope of getting to 12 psi before end of fermentation, at which point I cold crash. This allows me to ferment nearly 5 gallons without problem. By the time I am attaching spunding valve, foam not an issue. I have had to replace pressure gauge on spunding valve due to foam, and I don't want to do that again.

 

[SanPancho]

I've been looking at a number of articles and videos about fermenting in corny kegs. It seems like a good option (other than not getting a full 5gal batch). Many of them (including Brian at Short Circuited Brewers) recommend using a 1/2 inch silicone tube in place of the PRV as a blowoff tube. Why not just attach a QD to the gas post and run a line from there? Is it more likely to clog a poppet that way? It would seem to be the simpler solution, and could more easily ensure no oxygen enters the fermenter when removing it.

the better way in my opinion is to take the gas post off and just put the hose over the the male threads on the keg.

 

[odie]

the better way in my opinion is to take the gas post off and just put the hose over the the male threads on the keg.

look at the picture I posted...

 

[SanPancho]

look at the picture I posted...

Make me

 

[odie]

Don't even think about looking at that picture...

I double dog dare you...

 

[beersk]

I start fermentation in a bucket and when it gets to about 1.030 (right after high krausen), I transfer to keg to finish fermentation. At some point I will take the hit on the cost of a Tilt to aid this process. Then I run a gas to gas line to serving keg filled with starsan, and serving keg liquid out hose to bucket. when serving keg is empty (sitting on a scale), I then attach spunding valve to ferm keg in the hope of getting to 12 psi before end of fermentation, at which point I cold crash. This allows me to ferment nearly 5 gallons without problem. By the time I am attaching spunding valve, foam not an issue. I have had to replace pressure gauge on spunding valve due to foam, and I don't want to do that again.

Interesting process. You've never had an issue with a stuck fermentation from transferring that early in the fermentation?

 

[SanPancho]

Don't even think about looking at that picture...

I double dog dare you...

No way you hoser.

I cant get in trouble, already on double-secret probation.....