How much pressure can fermentation build up?

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kiwipen

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What is the highest pressure that yeast can build up during fermentation?
 

Soulshine2

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it could break glass ...hope for popping a carboy bung first.
 
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kiwipen

kiwipen

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Lets pretend it's in a strong steel tank, and also not care about how the beer will end up tasting.
 

Soulshine2

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Lets pretend it's in a strong steel tank, and also not care about how the beer will end up tasting.
ok, i dont keg but the possibility to keg prime exists. so... to answer your question there can be enough pressure to serve beer from a keg.
 

khannon

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https://www.researchgate.net/public...evisiae_from_cellular_to_molecular_approaches
and
https://www.ncbi.nlm.nih.gov/pubmed/16082465
are two studies that talk about effects of pressure on Saccharomyces Cerevisiae(beer yeast) I would imagine that they have a point where the pressure kills the yeast. so that is probably your theoretical max assuming you have a container to hold pressure and a way to keep the yeast producing until death..

However, unless you are looking at weaponizing beer, I'm not sure why this is important..
 

Dave Sarber

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Research bottle bombs. I'm no expert, but it takes about 25-27 psi to blow a mason jar (I think), probably less for a cheap beer bottle. Whether the yeast is dead or alive at this point is moot.
In a metal vessel, it could conceivably go higher. See above post about weaponizing beer. Beer pipe bombs are hard to fuse.
 

Soulshine2

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https://www.researchgate.net/public...evisiae_from_cellular_to_molecular_approaches
and
https://www.ncbi.nlm.nih.gov/pubmed/16082465
are two studies that talk about effects of pressure on Saccharomyces Cerevisiae(beer yeast) I would imagine that they have a point where the pressure kills the yeast. so that is probably your theoretical max assuming you have a container to hold pressure and a way to keep the yeast producing until death..

However, unless you are looking at weaponizing beer, I'm not sure why this is important..
I think you're confusing yeast death with what is actually dormancy...
we can kill yeast with high temperatures , we know that.
If we dont filter our beer theres still a trace amount of active yeast that could be used to propagate another batch, its been done. It has reached its limit in dissolved alcohol /CO2 manufacturing so it cant produce any more at least at the rate it was when actively fermenting. So when we leave that little bit of headspace in the bottle before the O2 absorbing cap goes on and set it on a shelf to prime, it has that space to further ferment the priming sugar/spiess and carbonate our finished beer ,leaving CO2 in that headspace, which gives the fizz and pressure when we pop the cap.
likewise if we chill it below its working range,it stops fermenting temporarily, dormancy . Heat it up a little and it'll restart given it has something available to eat , do bottle bombs in a warm basement ring a bell?
 

Robert65

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It would quickly exceed the limits of a keg, except that it will probably have killed the yeast first, and fermentation won't get far. Laboratories actually use pressure around 100 psi to sterilize things, it's as good or better than autoclaving. Not sure what the point is here.

BTW I like the idea of weaponizing beer. If a truce is called, you can celebrate with your remaining ordnance, once the foam settles.
 

Brooothru

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It would quickly exceed the limits of a keg, except that it will probably have killed the yeast first, and fermentation won't get far. Laboratories actually use pressure around 100 psi to sterilize things, it's as good or better than autoclaving. Not sure what the point is here.

BTW I like the idea of weaponizing beer. If a truce is called, you can celebrate with your remaining ordnance, once the foam settles.

"Make beer, not war!". At least I think that's what we said during the 70s. Dunno, it's all kinda hazy, man.
 

Vale71

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Starting at 12°P with 74% apparent attenuation and not considering headspace losses up to 17.5 bar or thereabouts at 20°C. The yeast probably won't quit prematurely but fermentation will become somewhat sluggish at some point. Of course to be able to handle such pressure you'd need to ferment in an actual armored tank...
 

Robert65

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Starting at 12°P with 74% apparent attenuation and not considering headspace losses up to 17.5 bar or thereabouts at 20°C. The yeast probably won't quit prematurely but fermentation will become somewhat sluggish at some point. Of course to be able to handle such pressure you'd need to ferment in an actual armored tank...
Okay, next calculations for you: what would be the carbonation in v/v in the finished beer, and how many miles/kilometers of beer line would be need to serve it? [emoji12]
 

Vale71

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Okay, next calculations for you: what would be the carbonation in v/v in the finished beer,

About 17 vols or 35 g/l.

and how many miles/kilometers of beer line would be need to serve it? [emoji12]

That depends on how far the tank is located from my living room. If you want me to do all the calculations for you you're going to have to let me drink the beer as well... ;):D
 

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I performed this experiment once by accident, the first time I used kviek yeast.

Fermented in a keg and forgot to pull the PRV or hook up a dip tube. 12 hours after yeast pitch, I went to check on it and pulled the PRV. Not sure what PSI level it achieved, but it sounded like an air cannon going off. The yeast finished fermentation just fine.

Fermentation generates 20-25 volumes of CO2. If it didn't kill the yeast (which it would), 20 volumes of CO2 at 65F would be 270 psi. I believe corny kegs are rates to 100-120 psi.
 

Brooothru

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Starting at 12°P with 74% apparent attenuation and not considering headspace losses up to 17.5 bar or thereabouts at 20°C. The yeast probably won't quit prematurely but fermentation will become somewhat sluggish at some point. Of course to be able to handle such pressure you'd need to ferment in an actual armored tank...

17 bar is well north of 250 psi. In a former life when flying off an aircraft carrier the tires were inflated to 300 psi of pure nitrogen. I never figured out who or how they got inflated to that level. And I never was in the vicinity when one blew. Never would want to be.

I have heard and FELT a tire blow on a B727, but it was only inflated to about 170 psi. That was too close.

Brooo Brother
 

Tennessee Brew

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What is the highest pressure that yeast can build up during fermentation?
I would think it is theoretically impossible to go beyond 50 PSI with natural fermentation because isn't yeast killed off starting around 50 PSI? We are planning to carbonate in plastic soda bottles which have around 12 -150 PSI rating. From my understanding this will never get beyond 50 PSI if even getting to that at all.
.. hey pro's.. am I wrong here?
 

Vale71

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I would think it is theoretically impossible to go beyond 50 PSI with natural fermentation because isn't yeast killed off starting around 50 PSI? We are planning to carbonate in plastic soda bottles which have around 12 -150 PSI rating. From my understanding this will never get beyond 50 PSI if even getting to that at all.
.. hey pro's.. am I wrong here?
Make that 500+ PSI and you're closer to the actual limit...
 

Vale71

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I was talking about pressure alone. I didn't imply that yeast can get to that through fermentation alone. The implication is that it's impossible for yeast to commit "Harakiri" through fermentation-induced pressure alone so that's never really an issue, contrary to what the poster I was replying to seemed to believe.
 

VikeMan

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I would think it is theoretically impossible to go beyond 50 PSI with natural fermentation because isn't yeast killed off starting around 50 PSI?

I've naturally carbonated kegged beers (to 4 volumes target) at room temp. Accordingly, the pressure got above 50 PSI, right to where it should have for the targeted 4 vols. (Side note: that includes a batch with Wyeast 3724, the one that supposedly "stalls" because of the miniscule pressure added by an airlock.)

I've also done 5 vols in champagne bottles (~66 PSI, but no way to measure) with no apparent issues. These bottles also included Brett, though. I don't know how Brett's tolerance to pressure compares with Sacch.
 

tld6008

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17 bar is well north of 250 psi. In a former life when flying off an aircraft carrier the tires were inflated to 300 psi of pure nitrogen. I never figured out who or how they got inflated to that level. And I never was in the vicinity when one blew. Never would want to be.

I have heard and FELT a tire blow on a B727, but it was only inflated to about 170 psi. That was too close.

Brooo Brother
17 bar is NOT well north of 250 psi
 

Brooothru

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I guess for accuracy sake we must specify Sea Level standard barometric pressure of 1013.1 millibars @ 15°C, measured at 0' Mean Sea Level.

We also need to differentiate, or at least specify, "what" PSI we are referencing. Is it PSIG (gauge) or PSIA (absolute)?
At 17 bar, PSIG is 249.9, but PSIA needs 14.7 psi (one additional bar of pressure) added to the reading (once again assuming standard atmospheric conditions). This would appear to result in a value of 264.6 "PSI" which is, well, North of 17 bar measured as PSIG.

Brooo Brother
 

tld6008

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I guess for accuracy sake we must specify Sea Level standard barometric pressure of 1013.1 millibars @ 15°C, measured at 0' Mean Sea Level.

We also need to differentiate, or at least specify, "what" PSI we are referencing. Is it PSIG (gauge) or PSIA (absolute)?
At 17 bar, PSIG is 249.9, but PSIA needs 14.7 psi (one additional bar of pressure) added to the reading (once again assuming standard atmospheric conditions). This would appear to result in a value of 264.6 "PSI" which is, well, North of 17 bar measured as PSIG.

Brooo Brother
14.7 psi is one atmosphere, 14.5 psi would better describe one bar
 

Dr_Jeff

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I have found kegs in my store room that were at ~90psi, one had too much priming sugar, I had just guesstimated and dumped some in, lesson learned, and another had a saison in it, and obviously kept going.
I have a pressure tester/spunding valve, and was just checking kegs when I discovered them.
 

VikeMan

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I have found kegs in my store room that were at ~90psi, one had too much priming sugar, I had just guesstimated and dumped some in, lesson learned,

Yikes. Assuming ~68F, that's over 6.5 volumes of CO2. I think that qualifies as a "highly carbonated" beer.
 

Brooothru

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Ahhh...

The combination to the memory banks is starting to fall back into place. Hectopascals is the common unit of measure for barometric pressure in international aviation, though domestically it is also often referenced in millibars and/or inches of mercury. Slowly but surely the United States is getting dragged (kicking and screaming BTW) into the world of metric measurements.

It's been a few years since I used those units of measure. Regards "newtons per meter squared" it would be a few decades. ✈
 

DuncB

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Regarding the original question how high a pressure. My best effort was to 35psi in fermentasaurus with a wheat beer when i fitted a non return connector to my spunding valve.

THis video perhaps not conclusive but does give some real world data.

 

m3B.eer

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Funny... I was looking also to see how much pressure could primary fermentation build, as I wanted to know also how much pressure could a keg tolerate. And I fell onto this post.

I was starting to read about pressure fermenting today, spunding valve... Controlling pressure to be released for 15 psi. So I was curious to know how much pressure could actually be released, if we could already control up to 15psi?

I brewed today a Belgian Saison style beer. Yeast that works at a higher temp range.

Maybe an hour after pitching, it was starting to bubble quite intensely. And it was time for me to go to bed. I do not have yet a spunding valve, and did not want a mess in the morning, so I thought "maybe you can unplug the blow-off tube, leave it be overnight, release the pressure in the morning and keep going, being awake you'd be controlling it better".

I ended up too worried to sleep, looking for information. Couldn't find anything on resources to see what can happen to beer on closed vessel fermentation. I think I saw that yeast can die under pressure, but 50 or even 220MPa is probably way out of the realm of my house to sustain.

Anyhow, I did not have the balls to keep this experiment going much longer. Went back to the keg, pressure released it. Shortly after it started pouring out of the valve. Kept going, felt it needed it. After a big mess at 1:40am later, it seems to be back on "control" with a blow-off tube.

Does anyone know if that can happen? Without major accident? Fermenting At least for 12h in a closed vessel during primary?

My goal was to have it under pressure for 12h then back at it with a blow off. I would have probably not avoided the mess in the am, but was curious about that...??
 

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You are experiencing the warm carbed bottle of beer being opened. When pressure fermenting there is a lot more gas in the beer, when you release the pressure it wants to normalise. Hence it foams up like a warm bottle of beer being opened. This as you know is messy.
My experience and the video suggests it as well that the yeast keeps going. If I want yeast expression I don't use pressure or just a minimal amount to control the krausen ( I do use a fermentasaurus so I can see what's going on), then dial up the pressure towards the end of fermentation to get the carbonation built up.
If I don't want much yeast character ( lager ) or a recipe that says WLP 001 I tend to use opshaug kveik and set the dial to 15 psi from the off and then turn it up more to get the correct vols of CO2 towards the end of ferment ( this is temp related of course).
Beware that if you pressure ferment and then release the pressure to dry hop you can get a real boilover with gassy beer nucleated with dry hops. I have my hops in the fermenter on magnets ready to move them in at the time I want and don't open the fermenter for this. It's much less hassle.
You really do need a spunding valve for safety and control.
 
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