Can I ferment completely closed in corny keg under pressure?

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redalert

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No airlock, pressure relief, or blowoff. I wait a month for everything to settle after fermentation, cold crash for another 2 weeks, then attach a gas post to relieve pressure. Has anybody tried this? Will the excess pressure be too high? will the yeast survive under that amount of pressure and make good beer?
 
I've never tested it out. I would pull the pressure release once or twice a day just to be safe.

Also be prepared for seriously reduced ester and phenolics. You'll probably also have slower than normal fermentation as a result of the pressure.
 
I've never tested it out. I would pull the pressure release once or twice a day just to be safe.

Also be prepared for seriously reduced ester and phenolics. You'll probably also have slower than normal fermentation as a result of the pressure.

I'm actually toying with the idea. The ester and phenolics reduction would be a bonus as it's a pils that I have in the corny. I'm just worried that the yeast cell walls cannot handle the pressure and will burst leading to autolysys. Also if I pull the pressure release won't I spray beer all over the place during active fermentation?
 
It's plausible. Again, I haven't tested it out, so I don't know.

I know that Sierra Nevada ferments warm and under a couple psi for their "lagers". This way they can get a quicker turn around and keep the right flavors.
 
redalert said:
No airlock, pressure relief, or blowoff. I wait a month for everything to settle after fermentation, cold crash for another 2 weeks, then attach a gas post to relieve pressure. Has anybody tried this? Will the excess pressure be too high? will the yeast survive under that amount of pressure and make good beer?

That's how some of the big guys do lagers in a week at 65+. The pressure supresses ester production. It'll be a subpar lager but it'll be drinkable.
 
Why subpar? because of the temps? and if so I was planning to ferment at 55F.

I don't know why, something about the yeast not being as healthy under a few psi as they would be if not. The comment above was just a reiteration of what I heard on the Jamil Show on one of the archived episodes when Jamil did a quick blip on it (off topic from the show if I recall correctly). I just thought I'd stick it in there as my own 2 cents :)
 
I think you are underestimating how much pressure will actually build up. If your doing 5 gallons in a corny it will be almost completely full and the amount of Co2 it puts off will be significant. If it doesn't blow the O-ring right out of the lid or worse it will definitely over carb the beer. My understanding is that the big guys begin to pinch back on the blow off lines later in the fermentation to use some of the Co2 to self carbonate. I think when they ferment under pressure to help increase fermentation time it is at something like 15psi which I imagine you will far exceed with a completely closed vessel.
 
I second the "you may be underestimating the pressure" thought. I ferment in cornies, and have had my gas tube plug up a few times. Once while trying to clear the obstruction, a piece of whole hop (followed by a shock wave of beer) blew out and hit me in the face almost hard enough to knock me over. That was my first "cleaning beer off the ceiling" moment. The amount of pressure (and beer foam) I've had to release when getting a plug even 2 or 3 days into fermentation is amazing.
 
Would the beer begin to actually carbonate? Isn't this technically what happens when you bottle with priming sugar? The co2 has no where to go so it is dissolved in the beer? I believe this happened to me once where the airlock clogged sometime in secondary and the whole carboy started to carbonate (back when I dis secondaries ;) ).
 
Yes it will carbonate. Many of the big boys do just that, towards the end of fermentation they pinch back on the blow off to build pressure in the vessel and begin to carbonate the beer. It saves on having to buy gas. But the amount being released by a vigorous primary fermentation is far more than you would want for that not to mention they usually don't do it until later into fermentation when less nasty stuff is coming off the fermentation. I think a normal relief valve on a corny is something like 150lbs. I don't know what the max pressure rating is on them but I imagine you could exceed it if you had no way to release any pressure. Another thought is how would you get it open? From the description you are talking about plugging the relief valve hole with a solid plug, fill the corny, pitch and close the lid. With no way to release the pressure you would have incredibly carbonated beer that assuming the vessel could hold the pressure would be dangerous to open through the lid.
 
I believe what the OP would be doing would be a federal felony...construction and detonation of a concussion bomb...

Realistically, you'd really hope the o-rings failed before the stainless. We used to make dry ice bombs out of 2-liter plastic bottles. It's amazing what sort of damage those little things could inflict...well, we used to make them until somebody informed us that what we were doing was a felony...
 
I think that as long as the relief valve is intact, it will do it's job before anything else would fail... Good to see I'm not the only one with this same view... :D

I've fermented in a corny too (one batch so far) but I pulled the relief valve out so that I could fit it with a bung and put an airlock in it's place. Since that's a high point in the keg, I didn't have any issue with foam-over (plus using fermcap in the boil helped)...

Personally, I wouldn't put it under pressure. Not to say it won't work, but we KNOW that having an airlock in place works well. If you wanted to save on gas, then you could try what's already posted about pulling the airlock/blow-off tube from the keg before fermentation is completed to get it to start to carbonate for you. Although, I'd probably just let it go until complete and bottle/keg it as normal.
 
Understand that primary fermentation under pressure will create some additional heat during fermentation. As well under approx >5 psi of pressure you begin to increase the rate of hydrogen sulfide and ethyl hexanoate production. Why not just pull the vent pin and twist in sideways so it sits in the open position? Then all you need to do is perhaps lay a piece of aluminum foil over the valve as an extra barrier if you want.
 
Why would you want to capture the initial stages of CO2 fermentation off gassing? It does not always smell that nice and I'd prefer it stays out of my beer. Best bet would be to follow the techniques outlined elsewhere on HBT for capturing the CO2 from the later stages of fermenting with a spunding valve set-up.
 
I'm not worried about the pressure, at least initially. I believe corny kegs are designed to hold 120psi. I doubt the fermentation would create that much pressure. My main concern is yeast viability and the end product, the beer. Since it's a pilsner, will nasty compounds like diacetyl stay in the finished product? I'm also not interested in capturing the Co2 for its own sake. At the end of fermentation I would transfer to serving keg and force carbonate. Perhaps later I would toy with the spunding valve. I'm interested in having as little contact with the wort/beer as possible post transfer to the primary fermentation tank, in our case, the corny keg. A set it and forget it method without blowoffs, airlocks, etc.
 
I think you are drastically underestimating the amount of pressure that will build up in that corny. Assuming it didn't explode you would still need a valve installed that you can open to release the pressure before you could ever get the lid open. Remember that those lids open into the keg. I really think you are going to end up with a keg you can't open that is full of highly pressurized beer or you are going to have a potentially dangerous explosion. Not to mention if you could get it open it would be so incredibly over carbonated from all that Co2 that it would be a foamy mess.
 
Ok, I see what you are saying about the transfer, so instead of relieving the pressure through the lid or a valve you would just rack it out the liquid out line. You better check to see what that beer line is rated for then because you have a damn good chance of blowing it apart as soon as you hook up the line.
 
Ok, I see what you are saying about the transfer, so instead of relieving the pressure through the lid or a valve you would just rack it out the liquid out line. You better check to see what that beer line is rated for then because you have a damn good chance of blowing it apart as soon as you hook up the line.

Yes that's definitely a concern. I don't think that soft poly tubing can handle the pressure though perhaps I take the keg outside after the 6 weeks in the closed corny and hook up the ball-lock disconnect and let it spray some of the beer, relieving pressure without the tube.
 
What temperature do you plane to ferment at?

I have brewed under pressure at a brewpub. It required a "special" yeast designed to ferment under pressure at 65F This was a lager yeast designed to tolerate 8-10 PSI. I closed off the blow-off section and adjusted the pressure relief valve to hold a roughly 9 psi. It sped up lager production from 8 weeks to two weeks. After primary fermentation was mostly over, I did raise the pressure relief valve to 12 psi. Most tanks in brewpubs are only rated to 15 psi.

You cannot re-use the yeast unless you decant it under pressure and slowly lower the pressure over the course of a week or so.

The beer was then slowly chilled over the course of a week to 40 F and then filtered under pressure. The serving tank had to be pressurized to prevent foaming.

This is no way was an "inferior" beer. I used this method a few times to produce some great Vienna and Bock beer.

Please be careful if you try this. Do use an adjustable pressure relief valve and a pressure gauge to know exactly what your beer is doing. Do not allow the beer to go over 15 psi.

You might want to check with White Labs and Wyeast to see if they have any particular stains that work better under pressure.
 
Since you don't seem to be listening:

"While soda kegs work well for the most part, they are not the ideal yeast storage vessel. They have two significant flaws. One is... The other is that the lids do not vent pressure until it reaches a very high level. Carbon dioxide can build up quickly in yeast slurry, and pressures as low as 20 pounds per square inch can prove fatal to yeast. It is necessary to leave the pressure valve open (and covered with foil) or to vent and shake the keg at least once a day to purge the excess pressure manually." (Yeast White and Zainasheff, pg 157)

In this situation, they're talking about storing an entire corny full of yeast slurry that was harvested from a commercial conical. In your case, you'll have an actively fermenting batch that is continuously producing HUGE amounts of CO2. With little headspace, the PSI will build up quickly. Doesn't it only take like 3-5 gravity points to carbonate a batch to 2.2vol?

I don't even think this is a "try it and see" experiment. My spidey senses are tingling...
 
No airlock, pressure relief, or blowoff. I wait a month for everything to settle after fermentation, cold crash for another 2 weeks, then attach a gas post to relieve pressure. Has anybody tried this? Will the excess pressure be too high? will the yeast survive under that amount of pressure and make good beer?

First, do a search. 2 clicks to this

Unless the corny pressure relief valve were disabled, it's going to vent around 100PSI.

True fer sure, whata mess!!

As long as he ain't doing it in YOUR kitchen, no harm in letting him learn. Don't be a ****** dude.

OK, you convinced me. I won't say nothing else......:D
 
What temperature do you plane to ferment at?

I was planning to ferment at 50F ish though after reading some of these posts, I'm hesitant to try this experiment. At this point I wouldn't even mind if the beer was ruined.

Since you don't seem to be listening:

In your case, you'll have an actively fermenting batch that is continuously producing HUGE amounts of CO2. With little headspace, the PSI will build up quickly. Doesn't it only take like 3-5 gravity points to carbonate a batch to 2.2vol?

You're correct but huge enough to rupture the keg ie. explosion? I doubt it.
 
Firstly I don't have time to find the link to my references but,
180g of sugar will produce 44.8 litres of CO2. A 5 gallon batch of 1.050 beer has the equivilant of 6.7 lbs of dextrose (3039 grams). This means that beer would be expected to make (3039 g / 180g * 44.8 l) 756 litres of CO2 (199 gallons).
Even if estimating that there is 6 gallons volume in a corney, that would bring the pressure inside the 1 gallon headspace to 199 atmospheres or..........2924 PSI = goodbye corney.
 
Firstly I don't have time to find the link to my references but,
180g of sugar will produce 44.8 litres of CO2. A 5 gallon batch of 1.050 beer has the equivilant of 6.7 lbs of dextrose (3039 grams). This means that beer would be expected to make (3039 g / 180g * 44.8 l) 756 litres of CO2 (199 gallons).
Even if estimating that there is 6 gallons volume in a corney, that would bring the pressure inside the 1 gallon headspace to 199 atmospheres or..........2924 PSI = goodbye corney.

Ouch. I'll take your word for it. Somehow I thought there would not be that much co2 production and I could simply ferment completely closed under pressure and when everything settled I would simply attach the ball-lock keg post and vent the keg losing some beer in the process. Thanks for the replies guys. I will not be trying this anytime soon at least not without some sort of pressure relief.
 
If you were [not trying to be a ****** here] stupid enough to bypass the safety measures on a corney (and I know plenty of people have, but are aware of the consequences), you would effectively be making a small version of this:

So, be prepared to do some repairs to your home if you do this.

However, I would imagine that if you left the pressure relief valve in place, it would be [relatively] more safe. I however, doubt any good could come from effectively beginning carbonation a few hours after fermentation.
 
Yeah, sounds dangerous to me. Consider that you can carb a keg completely with about 3 oz of corn sugar. So you want to throw something in with 10+ pounds of grain and not let off the pressure?

Sounds extremely dangerous and I wouldn't do it. You would be lucky if the Orings failed. You could go to look at the keg and have a poppet or pressure relief valve fly out with the force of a bullet. If you want to ferment in a closed keg, let the pressure out regularly or better yet, invest in a pressure relief valve where you can set a specific psi.
 
None of us were trying to be *****es I promise. This board is full of friendly people and all I and the others were trying to say without being too condescending was that this could go very bad. I am glad you decided against it for the time being. And Mattd2 thank you for doing the math work, I saw that equation while at work and didn't have time to work it out, I'm glad you did. Fermenting beer can produce an incredible amount of Co2 and sealing that in a closed vessel can be extremely dangerous, even more so while bypassing safety measures designed for the vessel.
 
You can still ferment in the corny, just not have it air/pressure tight. Install an airlock into it (you have three options built into the keg) and you're good to go... Just be sure to use some fermcap first, or install a blow-off tube for the first few days...
 
Just be sure to use some fermcap first, or install a blow-off tube for the first few days...

Or don't brew full 5 gallon batches. I have done 3 gallons of apfelwein and ginger beer (7% abv) in 5 gallon cornies with nothing more than my gas in hose stuck into a jar of water. Beer would probably pump out a bit more kruesen though ;)
 
I'd rather ferment closer to the 5 gallon mark, of beer, than closer to 3 gallons. I had zero issues with the batch that started in the corny. I actually picked up four 5.16 gallon Sanke kegs last week that I'll be using for both primaries/fermenting and aging in... Already have what I need to use two of them (bung for one, cap for the other)... Plan to get the parts to use the other two within the next few weeks. Planning on phasing out some of my PET carboys in favor of the kegs... Now, if only I could get my hands on some slim/tall 1/4 barrel kegs (for cheap money)... :rockin:
 
I went ahead and installed a blowoff tube in the "out" post. My "supermoon pils" will be happily fermenting in the coming days with pressure release:mug:
 
I went ahead and installed a blowoff tube in the "out" post. My "supermoon pils" will be happily fermenting in the coming days with pressure release:mug:

Nice... Let us know how things go... I'm really starting to enjoy using kegs for fermenting and aging... I think they're easier to move around than either carboys or buckets...
 
Nice... Let us know how things go... I'm really starting to enjoy using kegs for fermenting and aging... I think they're easier to move around than either carboys or buckets...

Yeah not to mention cleaning. I can't stand cleaning a grimy carboy.
 
I went ahead and installed a blowoff tube in the "out" post. My "supermoon pils" will be happily fermenting in the coming days with pressure release:mug:

umm if you put it on the "out" post any pressure build up inside the keg is going to push liquid out from the bottom not gas from the top, you want your blow off on the "IN" post, so your venting gas off the top.

unless of course you removed the pick up tube from the out post when installing the blow off then it wont matter.
 

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