Pressurized Closed Loop Corny Keg Fermenting

[SanPancho]

I am referring to the pressure that the yeast sees. That doesn't change.

im sorry, you seem to be saying that yeast in a fermenter sees static pressure throughout its fermentation?

but then when i point it out, you acknowledge that the hydrostatic is higher the deeper you go in the tank, ergo it is NOT a static pressure on yeast throughout a vessel and throughout the yeasts fermentation cycle.

i wasnt calling you out for being inaccurate to the nth decimal. i was saying you are misrepresenting the pressure situation in a conical tank of decent size/height.

but if you want to change the subject to the actual decimal value of ANSI water column, we can do that again. you nailed it, two decimals.

you win!

 

[schematix]

im sorry, you seem to be saying that yeast in a fermenter sees static pressure throughout its fermentation?

No the yeast sees the head pressure (constant) + the (variable) static pressure due to the depth it's at. At a minimum it sees the head pressure.

My point is simply that if you put pressure on a corny keg fermenter, you're going to roughly simulate a taller conical fermenter. Is it exact? No because during fermentation the yeast will circulate and see an average. But it will go through cycles of more and less pressure until the end when it starts to floccs, then experiences maximum pressure.

 

[SanPancho]

thank you for repeating my own statements to me.

we done?

 

[schematix]

Yah that's the beauty of the reply and quote function.

 

[stonebrewer]

@SanPancho - hate to make your head spin, but I generally under pitch to get more esters in my IPAs. I don't under pitch by a lot, but enough to encourage a more estery beer. Only for ales, only for IPAs, and I have no problems going G2G in a week. Only negative I have found to doing this is I occasionally finish 1-2 points above my target, but I really don't mind a smattering of sweetness in an IPA to balance the bitterness.

As far as believing that pros ferment under pressure (I don't think I said high pressure, I meant the same process I outlined that I do...0 PSI to 10ish, let it ferment mostly out, then cap to carb), I think if you do a few google searches or search pro brewer sites, you will find discussions like we are engaged in between pros about the pros and cons of this. I also have a few pro acquaintances who told me to do this (and to find a way to recirculate during fermentation, which I am working on, especially with cryo). Additionally, I got the idea originally from email exchanges with the founder of Trillium, JC Tetreault. He explained that if you are venting all that CO2 during fermentation, you are losing a lot of the aromatics from your dry hop. <shrug>

 

[Dog House Brew]

@SanPancho - hate to make your head spin, but I generally under pitch to get more esters in my IPAs. I don't under pitch by a lot, but enough to encourage a more estery beer. Only for ales, only for IPAs, and I have no problems going G2G in a week. Only negative I have found to doing this is I occasionally finish 1-2 points above my target, but I really don't mind a smattering of sweetness in an IPA to balance the bitterness.

As far as believing that pros ferment under pressure (I don't think I said high pressure, I meant the same process I outlined that I do...0 PSI to 10ish, let it ferment mostly out, then cap to carb), I think if you do a few google searches or search pro brewer sites, you will find discussions like we are engaged in between pros about the pros and cons of this. I also have a few pro acquaintances who told me to do this (and to find a way to recirculate during fermentation, which I am working on, especially with cryo). Additionally, I got the idea originally from email exchanges with the founder of Trillium, JC Tetreault. He explained that if you are venting all that CO2 during fermentation, you are losing a lot of the aromatics from your dry hop. <shrug>

So do you just adjust with a spunding valve to regulate the pressure?

 

[stonebrewer]

@Dog House Brew : Yes, that is how I regulate pressure...a simple spunding valve, which is just a screw, a weight with an o-ring, and spring and tubing/parts to connect to the keg. Simple device. The screw pushes the weight by compressing the spring, sealing a cylinder with the o-ring. Pressure from the tank pushes the other direction. When it gets enough pressure, it pushes the weight out of the way and gas escapes, lowering the pressure, and the spring pushes the opening closed again. I also have a pressure gauge attached to it to read the pressure. It is a 0-60 PSI gauge, which is a bit overkill...0-30PSI would work as well and give a little better granularity.

 

[jekeane]

Im brewing a Maibock this weekend and am considering giving this a try. I have a spunding valve and would like to carbonate without adding sugar if I catch it at the right time. Are you adjusting your normal fermentation temperatures during this process? I generally pitch my lagers around 46° and set to 48° with a self rise to 50° after a few days. I do a diacetyl rest in the 60's after a two weeks.

 

[schematix]

Diacetyl rest is complete unnecessary if you pitch enough healthy yeast. Definitely a band-aid fix for a bigger problem.

I usually aim for 48F and then slowly start to lower it as the racking / spunding point is reached, and continue to lower it down to 30F for lagering.

 

[arrasmithf]

I actually used white labs wlp925 high pressure lager yeast. It's designed to be fermented at 68F and 15psi.I'm new to the pressure fermentation but seems like it's going well. Taking my first reading/tasting tomorrow and I will update. It's kind of maddening not being able to see the activity like in a carboy tho. Can't wait!

 

[NZhomebrew]

Hey guys, I've tried this method three times with pale ales and I am having issues with diacetyl. The first two times I pitched US05 and fermented at 68 degrees at 24psi for 2 weeks, both with strong diacetyl taste when transferred to the serving keg. The third time is used 1056 and fermented at 0psi at 65 degrees for 4 days then let it gradually increase to 18psi for another week at 71 degrees, again diacetyl although less and the first two times.

I have brewed successful batches in between using the traditional methods not under pressure which have turned out good so i can discount infection.

I am fermenting in 5 gallon cornys. I have not tried with larger at all.

Does anyone have any ideas on how to prevent diacetyl for my next attempt? I am about to give up and stick with traditional fermenting.

 

[schematix]

How much US05 did you pitch and what was the OG?

 

[NZhomebrew]

How much US05 did you pitch and what was the OG?

I pitched 1 packet rehydrated into a 2.5 gallon batch.

For the 1056, i eastimate to have pitched between 100 - 150 billon cells into 2.5 gallons.

 

[tubatrub]

This thread kicks ass! Thanks schematix and others who have contributed.

Here is my setup, pressure tested and ready to go. Planning to try it next batch. Couple questions...

I have a double IPA kit. 1.08 OG. The kit came with one Safale US-05 packet, and instructions said to NOT rehydrate the yeast. For a few reasons I was confused by this, as my inclination would be to do a big yeast starter. If I just pitched dry yeast as recommended, and a few drops of fermcap, should I still be concerned with blowoff or clogging the poppet? How about with a big starter and fermcap?

I added the filter housing to be able to somewhat monitor fermentation. Maybe unnecessary (since the PRV is on the serving keg), but I figure it's also extra security to keep any krausen away from the PRV. Also, has anyone tried using filter housing to add a hop tea during transfer to the serving keg?

My plan is to ferment at 3-5psi for the first day or two, crank up to 10-15 for a few days, then when I am about 2 points from FG (picnic tap for samples when things start to settle down), crank it up to 30 and hopefully hit my target. I would then cold crash for a few days, transfer and serve.

Thoughts on a doing yeast starter? Pressure schedule recommendations? Super stoked to give this a try!

 

[schematix]

Looks like you're ready to go.

How big is your kit? If its 5 gallons of 1.080 i'd use at least 3 packs of US-05.

US-05 is a huge top cropping yeast. If you're doing 4+ gallons in there you need to be aware that filter housing may fill up!

 

[tubatrub]

Looks like you're ready to go.

How big is your kit? If its 5 gallons of 1.080 i'd use at least 3 packs of US-05.

US-05 is a huge top cropping yeast. If you're doing 4+ gallons in there you need to be aware that filter housing may fill up!

Yes, 5 gallons. Thanks for the tip on the yeast strain! For that reason I am also considering 4 gallons of wort in the FV with one gallon of clean water waiting and being purged in the SV.

 

[schematix]

Don’t do that unless you completely deoxygenate the water in the serving keg. Not easily accomplished!

 

[Veets]

This thread kicks ass! Thanks schematix and others who have contributed.

Here is my setup, pressure tested and ready to go. Planning to try it next batch. Couple questions...

I have a double IPA kit. 1.08 OG. The kit came with one Safale US-05 packet, and instructions said to NOT rehydrate the yeast. For a few reasons I was confused by this, as my inclination would be to do a big yeast starter. If I just pitched dry yeast as recommended, and a few drops of fermcap, should I still be concerned with blowoff or clogging the poppet? How about with a big starter and fermcap?

I added the filter housing to be able to somewhat monitor fermentation. Maybe unnecessary (since the PRV is on the serving keg), but I figure it's also extra security to keep any krausen away from the PRV. Also, has anyone tried using filter housing to add a hop tea during transfer to the serving keg?

My plan is to ferment at 3-5psi for the first day or two, crank up to 10-15 for a few days, then when I am about 2 points from FG (picnic tap for samples when things start to settle down), crank it up to 30 and hopefully hit my target. I would then cold crash for a few days, transfer and serve.

Thoughts on a doing yeast starter? Pressure schedule recommendations? Super stoked to give this a try!

Any results yet?

I did a filter housing setup, but disconnected it after the first week or so and didn't hook it up again. I hooked the PRV directly to the fermenter at that point, and left the SK at something like 5PSI.

I'm struggling to imagine how you could use the filter housing to catch krausen during the fermentation, and then later for hop tea, without opening it up and introducing O2.

On a somewhat related idea, I was messing around trying to fix what I thought was a stuck fermentation batch one time, and used one of those carbcap gizmos to inject liquid right into the serving keg (it could have been the fermenter keg, if I had desired). The carbcap was the type with the barb on the inside. I hooked up a length of hose, maybe 6 inches, so that it would draw from the bottom of a plastic soda bottle I hooked it up to. Filled the soda bottle with the yeast mixture, purged the headspace by squeezing the bottle most of the way, and then hit it with CO2 to get it up to 30 or 40 PSI. When I then hooked that bottle up to the SK (via the gas port, I think) , the liquid in the soda bottle shot right into the keg due to the pressure differential. The SK was around 10 or 12 PSI. I think I read the idea on this board somewhere (maybe even this thread!), and it works.

You could probably do the same for your hop tea, but as mentioned above if you don't deoxygenate it then you're losing the benefit of the closed system and low O2 levels.

Also, for what it's worth, my fermentation was not stuck and adding yeast didn't help. I wouldn't recommend it to anyone. And come to think of it, I now wonder if the 30-40 PSI, even for just a minute or two, killed the yeast. That hadn't occurred to me before, but I suppose it could be true.

 

[SanPancho]

Any results yet?


On a somewhat related idea, I was messing around trying to fix what I thought was a stuck fermentation batch one time, and used one of those carbcap gizmos to inject liquid right into the serving keg (it could have been the fermenter keg, if I had desired). The carbcap was the type with the barb on the inside. I hooked up a length of hose, maybe 6 inches, so that it would draw from the bottom of a plastic soda bottle I hooked it up to. Filled the soda bottle with the yeast mixture, purged the headspace by squeezing the bottle most of the way, and then hit it with CO2 to get it up to 30 or 40 PSI. When I then hooked that bottle up to the SK (via the gas port, I think) , the liquid in the soda bottle shot right into the keg due to the pressure differential. The SK was around 10 or 12 PSI. I think I read the idea on this board somewhere (maybe even this thread!), and it works.

how did you connect to the QD on the keg? QD to QD with just some tubing or something? An MFL to MFL coupler?

 

[Veets]

Yes, QD to QD

 

[degivens]

Time for a dumb idea...feel free to tell me what I am missing:

Setup - I have a Zymatic, so I do smaller 3 gallon batches. Keep that in mind. Means a lot more headspace in the keg and thus a lot more oxygen, so I have to purge the kegs of O2 or the batches get brown in a week or less. I ferment under pressure with a spunding valve and have regularly kept it set at 20 PSI without any issues. Fermentation is usually done in about a week. I have a clear draught system in my serving keg with a stainless screen I designed/built over the intake.

Here's the idea - instead of (or in addition too?) water purging the serving vessel, why not just push a half gallon or so over from the FV while at peak fermentation? Yeast move over with some wort, eat all the O2, and Bob's your uncle? I am a firm believer of the KISS principle (yeah, even though I am a DIY homebrewer!) and it seems to me that this might work well. What am I missing here? Could even work for the times when I use my larger system for 5 or 10 gallon batches.

How are you transferring from your primary keg to your serving vessel if the serving vessel has a filter over the intake (seems like it would clog up almost instantly when transferring)? Are you transferring into the gas side of your serving vessel or am I dumb and missing something?

Also out of curiosity have you tried just serving from the primary vessel with the clear beer + filter setup...?

 

[SanPancho]

i was wondering the same thing. you'd have to fill on the gas side, no?

speaking of clear beer, anybody used the floating dip tube from the fermentasaurus? same principle, $9 from morebeer.

 

[leesmith]

i was wondering the same thing. you'd have to fill on the gas side, no?

speaking of clear beer, anybody used the floating dip tube from the fermentasaurus? same principle, $9 from morebeer.

I just took a look at that. Does it have a filter on the end? My concern would be clogging it with hops but that's a great price.

 

[SanPancho]

The whole point is that it negates the need for a filter by floating.

If you really want a filter they also sell a dip tube screen you could probably slip on somehow.

I have a dip tube filter. Not the fermentasaurus floater tho. Just guessing based on photos of the unit. Seems like you could make it work.

 

[leesmith]

The whole point is that it negates the need for a filter by floating.

If you really want a filter they also sell a dip tube screen you could probably slip on somehow.

I have a dip tube filter. Not the fermentasaurus floater tho. Just guessing based on photos of the unit. Seems like you could make it work.

Even the clear beer thing sells a filter for their system so somebody must have clogged it at one time. I could see disturbing the trub/dry hops and causing it to get sucked up in there.

Anyways....which filter do you use on your dip tube and how do you like it? I'm considering getting one.

 

[SanPancho]

I cant remember if i got it at morebeer or AIH. I used it when i fermented in cornys. Put another gasket over it to fully seal it on the tube (same one from the top of the dip tube/post). Kept hops out, but tiny particles did get through a bit. And i neverr seemed to get the right length on a shortened dip tube so now i just ferment in carboy and pressure transfer to keg for carbing.

 

[stonebrewer]

How are you transferring from your primary keg to your serving vessel if the serving vessel has a filter over the intake (seems like it would clog up almost instantly when transferring)? Are you transferring into the gas side of your serving vessel or am I dumb and missing something?

Also out of curiosity have you tried just serving from the primary vessel with the clear beer + filter setup...?

I haven't tried this setup yet, but I would almost certainly transfer into the gas side to avoid clogging the clear draught filter. I have not tried serving from primary and am waiting anxiously for someone to report back on how that worked for them (hint, hint, ...) so I can decide whether or not to try it as well. I suspect that will lead to problems with a large hop load, but maybe not!

 

[stickyfinger]

What would be your reply to this post?

http://scottjanish.com/fermenting-dry-hopping-pressure/

It seems some people I've read about online didn't get as good of flavor fermenting under pressure (at least at the end.) Do you think it was just a fluke? Has anyone done a batch exactly the same except one is partially under pressure with closed transfers vs just racking from a carboy to a purged keg and carbonating with a CO2 cylinder? Just curious if you can tell doing a side by side. I'm interested in setting up one of these to play around with, but my main concerns are clogging the lines as I can't get perfect wort into my fermenter and I like loose dry hops not bagged (though I am willing to try bagging them.)

 

[schematix]

Forced carbonation is no good, no matter how you transfer.

I'd be really weary of free balling hops into a keg. The poppet designs are not at all clog tolerant. You're asking for troubles.

 

[Hannabrew]

I'm using the fermentasaurus floating dip tubes in my kegs (and 2 CB with filters) and they work great. As for filters, I think the main purpose of the filter for the CB is for whole hops as they float...pellets will drop so I free hop in the keg for both floating dip tubes.