Pressurized Closed Loop Corny Keg Fermenting

[mccabedoug]

I'm using this technique (kind of) for a NE IPA using Tree House yeast from a couple cans of Julius. Fermented in a bucket with tons of dry hops in a paint bag. With about 4 points to go I transferred to dry hopping keg with a bunch more hops in 3 tea balls. That is where the beer is now. Questions I have at this point:

1) what are you setting your sounding valve while the fermentation completes? If possible, I'd like the beer to be carbed up when I transfer to serving keg.

2) do you cold crash in the dry hop keg or will the beer first see cold temps in the serving keg?

Thanks.

 

[crane]

I'm using this technique (kind of) for a NE IPA using Tree House yeast from a couple cans of Julius. Fermented in a bucket with tons of dry hops in a paint bag. With about 4 points to go I transferred to dry hopping keg with a bunch more hops in 3 tea balls. That is where the beer is now. Questions I have at this point:

1) what are you setting your sounding valve while the fermentation completes? If possible, I'd like the beer to be carbed up when I transfer to serving keg.

2) do you cold crash in the dry hop keg or will the beer first see cold temps in the serving keg?

Thanks.

I'm not the OP, but here is what I do.

1) At the end I set my spunding valve for 20-25psi to get full carbonation at room temp. Use one of the online calculators or graphs to figure out what pressure to set it at for your target volumes of CO2 and current beer temperature.

2) I cold crash in the dry hop keg before transferring if I transfer at all. I've gotten lazy lately and just serve from the dry hop keg. I haven't observed any adverse flavors from leaving the dry hops in while serving.

 

[mccabedoug]

I'm not the OP, but here is what I do.

1) At the end I set my spunding valve for 20-25psi to get full carbonation at room temp. Use one of the online calculators or graphs to figure out what pressure to set it at for your target volumes of CO2 and current beer temperature.

2) I cold crash in the dry hop keg before transferring if I transfer at all. I've gotten lazy lately and just serve from the dry hop keg. I haven't observed any adverse flavors from leaving the dry hops in while serving.

Thanks. That's pretty straightforward. Have you shortened your liquid dip tube? I haven't and was wondering what to expect with trub.

 

[schematix]

Dry hop with the 4-6 points remaining. Set 10-15 psi. This will give yeast chance to scrub o2 and biotransform.

Few days later inject priming sugar solution into FV, wait an hour, rack and then seal up SK, or set spund to 30-35 psi. This will ensure low oxygen environment for SK.

 

[oujens]

Schematix, how do you oxygenate the wort after pitching the yeast? Also curious how long you do it for ales and lagers. I missed the LoDO recommendation that you stir and oxygenate for a few minutes to achieve the desired level of oxygen. Curious if this might also be why I had residual sulfur - not oxygenating enough.

 

[schematix]

Schematix, how do you oxygenate the wort after pitching the yeast? Also curious how long you do it for ales and lagers. I missed the LoDO recommendation that you stir and oxygenate for a few minutes to achieve the desired level of oxygen. Curious if this might also be why I had residual sulfur - not oxygenating enough.

I use pure o2 and a half micron stainless stone on a 2' stainless shaft.

Pop the lid, oxygenate for about 2 minutes at 1/4 Lpm (generates very few surface bubbles for me) put the lid back on, do a few CO2 purge cycles (otherwise you're going to push oxygen rich air into the SK, defeating the efforts of water purging).

I usually wait a few hours after doing this before re-connecting the FV to the SK to give the O2 time to be absorbed in the FV.

 

[TomRep]

So silly question, and sorry if this has come up before. But, co2 is heavier than atmospheric air. The little bit of headspace left from oxgenating the wort should easily blow out of the SK, especially with all the co2 coming a few hours later when the fermentation kicks in, no?

 

[schematix]

So silly question, and sorry if this has come up before. But, co2 is heavier than atmospheric air. The little bit of headspace left from oxgenating the wort should easily blow out of the SK, especially with all the co2 coming a few hours later when the fermentation kicks in, no?

Doesn't work like that. The gases mix and then you're playing the dilution game, and you won't win.

The more i think about it, I think a revision to the method is in order. The FV shouldn't be connected to the SK until after fermentation has started, allowing the FV headspace to be purged several times over so that oxygen rich air won't enter the SK when the two are connected.

Unfortunately it doesn't appear that i can edit the OP anymore... didn't know there was a time limit???

 

[oujens]

Doesn't work like that. The gases mix and then you're playing the dilution game, and you won't win.

The more i think about it, I think a revision to the method is in order. The FV shouldn't be connected to the SK until after fermentation has started, allowing the FV headspace to be purged several times over so that oxygen rich air won't enter the SK when the two are connected.

Unfortunately it doesn't appear that i can edit the OP anymore... didn't know there was a time limit???

I was thinking about this too. I think I'll start with a blowoff and then connect the kegs after its had long enough to clear the headspace of any oxygen.

 

[RoatanBill]

schematix:

As I understand the concern, O2 is good (food) for the yeast while the liquid is wort, and it is bad once the wort converts to beer. Trouble is, this isn't a step function; it's a continuum. We know when wort is wort and we know when beer is beer, but during fermentation, we have a bit of both to varying degrees as time progresses. I believe the law says it's beer once the yeast is pitched, for example.

Those that add O2 to the wort initially have no absolute guarantee that some of it won't come out of suspension for hours after the keg's been sealed. That would increase the O2 concentration above ambient and would theoretically be bad for the quasi wort/beer. Those that just bubble air through the wort do not increase the chances of increasing O2 concentration.

Wouldn't the smart move be to just use air to aerate the wort and then after X hours blow CO2 into the keg's head space to get rid of 99.9% of the "air" replacing it with CO2 and then connect the SK?

 

[jmcquesten]

Here's my spunding manifold at work. I had bad luck with "daisy-chaining" kegs together, so I came up with this. It's much better than trying to jump from gas to liquid on multiple kegs. I'm pressure fermenting with this setup right now for the first time.

View attachment 1492331630206.jpg

 

[pigroaster]

Could you post a list and suppliers of needed equipment to do this? Looks great! Thanks for posting.

 

[jmcquesten]

Could you post a list and suppliers of needed equipment to do this? Looks great! Thanks for posting.

Sure. Here are a few more pictures. Most of the parts can be found at a homebrew shop and a large hardware store. I had the stainless block machined, so no supplier on that one but there's an easy substitution.

1. Spunding valve - Amazon

2. 0 - 30 psi gauge (1/4" npt threads) - eBay or Amazon

3. 3 - 1/4" npt to 5/16" barb fittings (or 1/4" npt shut-off valves with hose barbs and NO check valves). Hardware store or homebrew supplier if using shut-off valves.

4. 3 - 5/16" swivel connectors to connect to grey keg gas disconnects. Homebrew shop

5. 3 - grey keg gas disconnects. Homebrew shop

6. 5/16" gas tubing (I used thick wall to handle pressure build up). Homebrew shop

7. Machined stainless block with 5 holes tapped to 1/4" npt thread. In place of this, a 1/4" cross fitting can be used. 3 hoses would connect to 3 legs of the cross (with barb fittings), the 4th would have a short 1/4" pipe nipple going into a tee, the other 2 legs of the tee would get the gauge and the spunding valve. I can send pictures of what that would look like if needed. If you need more info on the spunding valve, shut-off valves, or gauge, I can search and send links.

View attachment 1492379819271.jpg

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[jmcquesten]

Here is another way to set it up without the machined block. The fittings (other than that shut-off valves) came from a hardware store. The top silver fitting above the gauge is where I had the spunding valve. The hose barb fitting on the right side of the cross is all that's necessary, but I had the shut-offs (left side of cross), so I used them. It's also nice being able to further isolate each line in case any issues come up.

View attachment 1492381952567.jpg

 

[jmcquesten]

I was originally going to use one of these. There is a plug on each end. One for the spunding valve, one for the gauge. Then 3 hose connections. You have to be careful with these though because you can't use the shut-offs with check valves in them because the flow is going the opposite direction.

 

[RoatanBill]

jmcquesten:

If you have no check valves then one tank with vigorous fermentation going on will push its gas into the other two kegs. If one keg has an issue, then it could pollute the other two. Even good gas will push flavors from one keg to the others.

Why no check valves?

When fermentation is done per keg, how do you plan to proceed to get the finished beer into a serving situation?

 

[jmcquesten]

jmcquesten:

If you have no check valves then one tank with vigorous fermentation going on will push its gas into the other two kegs. If one keg has an issue, then it could pollute the other two. Even good gas will push flavors from one keg to the others.

Why no check valves?

When fermentation is done per keg, how do you plan to proceed to get the finished beer into a serving situation?

This is somewhat correct. It does depend on all the kegs equalizing each other, but with all kegs (theoretically) pressurizing at the same rate (all the same beer), I'm not worried about gas "polluting" the other kegs.

I said no check valves because the check valves in shutoff valves are going the wrong direction. You could use inline check valves going away from the kegs, but it's really not necessary. I plan to use this only on the same batch. I won't use it for different beers at the same time. If I decide to ferment different beers at the same time with this setup, I would want inline check valves to keep things separated. I'm splitting an 11 gallon batch between 3 kegs before consolidating it into 2 full kegs.

After fermentation is complete, I'll pressure transfer to a clean, purged serving keg.

 

[pigroaster]

If you could send/post more information on spunding valve and specific source you would be awesome. I live in the woods in Canada so this type of information is hard to get with the technology I have. I can machine a block so no issues there. Thanks.

 

[jmcquesten]

Here is the spunding valve I used from Amazon. I also did a quick amazon search for a gauge. This is not the same one I have, but something similar should work. Make sure it's a 0-30 psi gauge for fine adjustments.

Spunding valve:
https://www.amazon.com/gp/product/B007GDY3CU/?tag=skimlinks_replacement-20



Gauge:

https://www.amazon.com/gp/product/B005P00OYC/?tag=skimlinks_replacement-20

View attachment 1492431986620.jpg

 

[RoatanBill]

jmcquesten:

Thank you for your reply.

I'm considering putting a container between the FV and the spunding valve to catch crud. From what I've read, having pressure in the FV reduces the level of foam produced, so human nature would want to fill the FV closer and closer to the nominal 5G maximum. At some point, Murphy of Murphy's Law fame, will appear and crud will exit the FV and I'd prefer it go into another vessel that can keep it from polluting the valve or worse.

At 5PSI, I think almost anything can handle that pressure. I've considered a mason jar with a modified lid wrapped in a towel for testing. I could even hook the jar up to my air compressor and keep increasing PSI till it blows to see where failure might lurk.

 

[schematix]

jmcquesten:

Thank you for your reply.

I'm considering putting a container between the FV and the spunding valve to catch crud. From what I've read, having pressure in the FV reduces the level of foam produced, so human nature would want to fill the FV closer and closer to the nominal 5G maximum. At some point, Murphy of Murphy's Law fame, will appear and crud will exit the FV and I'd prefer it go into another vessel that can keep it from polluting the valve or worse.

At 5PSI, I think almost anything can handle that pressure. I've considered a mason jar with a modified lid wrapped in a towel for testing. I could even hook the jar up to my air compressor and keep increasing PSI till it blows to see where failure might lurk.

Personally I would use a water filter canister and just leave the filter out. They are cheap and hold as much pressure as a corny keg will.

Per post #1, you can jump the FV gas port right to the liquid port on the SK. I've had a lot of blow off before, so once things subsided i burped the FV PRV and it caused the 'lost' beer to flow right back into the FV, further improving yield. Ideally i want 0 blow off though so this isn't something i want to make routine.

 

[jmcquesten]

This is why I am fermenting 11 gallons in 3 kegs. Didn't want the chance of blowoff. I'll combine it into 2 kegs before serving.

 

[jimmypop13]

I love this idea and am thinking about ordering a few kegs to try it out. I have a few questions I was hoping you could help me with.

1. I saw Brew Hardware has https://www.brewhardware.com/ProductDetails.asp?ProductCode=TW18-L-14-R&CartID=1 and https://www.brewhardware.com/ProductDetails.asp?ProductCode=MWL14ThermoWell&CartID=2
Do you think this would hold pressure on a corny keg lid? Or would your one-off lids from Nor-Cal be better/cheaper?

2. What is your reason for using priming sugar instead of co2 to carbonate?

3. Why did you bend the diptube in the FV instead of just cutting off an inch or so?

Thanks

 

[schematix]

I love this idea and am thinking about ordering a few kegs to try it out. I have a few questions I was hoping you could help me with.

1. I saw Brew Hardware has https://www.brewhardware.com/ProductDetails.asp?ProductCode=TW18-L-14-R&CartID=1 and https://www.brewhardware.com/ProductDetails.asp?ProductCode=MWL14ThermoWell&CartID=2
Do you think this would hold pressure on a corny keg lid? Or would your one-off lids from Nor-Cal be better/cheaper?

2. What is your reason for using priming sugar instead of co2 to carbonate?

3. Why did you bend the diptube in the FV instead of just cutting off an inch or so?

Thanks

1. It was only slightly more expensive to get the welded lids custom made from Nor Cal. You also don't have to sacrifice an otherwise good lid.

2. 2 reasons. Most importantly, active yeast scavenge oxygen, which is critical to having near 0 levels of oxygen in the serving keg. Second is that canister CO2 isn't pure. Even 0.1% oxygen in the keg (a realistic amount) is more than enough to stale the beer.

3. Because it's reversible. I can re-bend to tweak the amount of pick-up (which i've done few times). One day i hope to own a glycol jacketed pressure rated conical fermenter, then these kegs can go back to their original function without repurchasing any pieces.

 

[oujens]

Have my beer fermenting with this setup for the first time. Minor hiccup on my part but so far it's worked out pretty good. My spunding valve is around 6 psi so I'll leave it and dial it back when I transfer. Out of curiosity, do I need to use 3/16 ID hose for the liquid, or can it still transfer with 5/16 ID. I have more of the latter in hand. Didn't think about the hose size until now.

 

[schematix]

Have my beer fermenting with this setup for the first time. Minor hiccup on my part but so far it's worked out pretty good. My spunding valve is around 6 psi so I'll leave it and dial it back when I transfer. Out of curiosity, do I need to use 3/16 ID hose for the liquid, or can it still transfer with 5/16 ID. I have more of the latter in hand. Didn't think about the hose size until now.

I think 5/16 would work. If anything it's just larger than it needs to be because the other tubes in the keg are 3/16 or 1/4".

Good luck!

 

[oujens]

I'll provide an update on my experience. I had one of those "oh sh!t" moments that we all probably experience one time during a brew process. Mine happened on transfer but is more a fault of my equipment. The keg I fermented is tricky to get the lid sealed up. I had not used it in a while and thought I had it seated. When I tried to transfer, the pressure dropped low enough that the co2 escaped out of the lid. Not the end of the world though. I simply hooked the FV to my co2 tank and started pushing into the SV while using the spunding valve to relieve pressure from the SV. This systems works nicely (would have if not for my fault). My first time fermenting in a keg was great. Thanks again for the write up, schematix. I'll get this lid taken care of and give it another go next time.

 

[kshuler]

subbed

 

[Hannabrew]

I am following this process as far as the SV is concerned however I am still using a PET carboy for the FV. I dry hop in the primary so my fermentation is complete and I'd like to transfer to the SV. Does it still make sense to add a priming solution to the carboy to try and get some additional fermentation going? To do so I would need to remove the bung momentarily which I would think would introduce O2 but perhaps the additional fermentation is worth a little O2 intake considering it will push it out anyway.

 

[schematix]

I am following this process as far as the SV is concerned however I am still using a PET carboy for the FV. I dry hop in the primary so my fermentation is complete and I'd like to transfer to the SV. Does it still make sense to add a priming solution to the carboy to try and get some additional fermentation going? To do so I would need to remove the bung momentarily which I would think would introduce O2 but perhaps the additional fermentation is worth a little O2 intake considering it will push it out anyway.

-Dry hop before the fermentation is totally complete. I realize its difficult to get a gravity sample from a carboy so visually may be your best bed. This will be around the time the kraussen starts to fall but you still see floaters bubbling around.

-If you're racking at FG then definitely add the priming sugar and wait until fermentation restarts (probably an hour or less). Then rack under CO2 pressure into the purged keg. Try to just barely lift the bung, inject the solution, then cap it back up.

-Get it out of the ferm as quickly as possible. Keep your dry hop to a day or two if you can.