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Brews & Views Bulletin Board Service * Brews and Views Archive 2008 * Archive through July 11, 2008 * Yeast Performance Versus Pressure < Previous Next >

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priorm
Junior Member
Username: Priorm

Post Number: 69
Registered: 01-2006
Posted From: 96.245.18.31
Posted on Friday, June 27, 2008 - 10:18 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I'm fermenting 5 gallons of IPA in a 10 gallon keg and would like to naturally carbonate the beer. I'm at 1.021 now and expect to finish around 1.016 - 1.018. I'm curious if anyone can comment on the impacts of pressure on yeast. I understand that increased pressure can kill the yeast and increase ester production. I'm using WLP51 - White Labs California V yeast. I don't recall at what PSI these effects occur. Does anyone know? Are there any other effects that I should be concerned with? Note: I have a variable pressure relief valve connect to this keg right now. It is set to release the pressure at 16 PSI, for the moment.
 

Tom Gardner
Senior Member
Username: Tom

Post Number: 1112
Registered: 01-2001
Posted From: 162.119.64.100
Posted on Friday, June 27, 2008 - 10:37 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

You should be fine to use the pressure relief valve. Although I don't know if that will be high enough to fully carbonate it. Just check your usual carbonation pressure vs temperature chart.
Brew on, Tom

(Message edited by tom on June 27, 2008)
 

priorm
Junior Member
Username: Priorm

Post Number: 70
Registered: 01-2006
Posted From: 96.245.18.31
Posted on Monday, June 30, 2008 - 12:59 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I feel comfortable with my procedure. I'm really looking for references regarding this topic. Does anyone have anything? Or perhaps was it covered in past threads? I tried to search for this with no luck.
 

Don Lund
Member
Username: Donlund

Post Number: 104
Registered: 10-2003
Posted From: 71.178.111.215
Posted on Monday, June 30, 2008 - 04:12 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I don't have references for you, just some experience. For a couple years now I've been fermenting my beers under pressure, normally up to 35 psi or so. Doing this doesn't seem to adversely affect the quality of the beer, and the beers ferment down to normal final gravities.
 

Dan Listermann
Senior Member
Username: Listermann

Post Number: 5678
Registered: 03-2004
Posted From: 74.215.70.152
Posted on Monday, June 30, 2008 - 02:00 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I doubt that pressure bothers yeast much anymore than pressure bothers divers. How much pressure does it take to blow up a bottle?
 

priorm
Junior Member
Username: Priorm

Post Number: 71
Registered: 01-2006
Posted From: 162.44.245.51
Posted on Monday, June 30, 2008 - 05:11 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Don,

Thanks for the reference point. 35 PSI is higher than I expected.
 

priorm
Junior Member
Username: Priorm

Post Number: 72
Registered: 01-2006
Posted From: 162.44.245.51
Posted on Tuesday, July 01, 2008 - 06:44 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Don,

Do you repitch your yeast after fermenting under 35 PSI?
 

Graham Cox
Senior Member
Username: T2driver

Post Number: 1767
Registered: 11-2004
Posted From: 68.32.253.156
Posted on Tuesday, July 01, 2008 - 07:31 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

priorm, I've spent a few minutes unsuccessfully trying to find the reference(s) that I have read on this subject. My (perhaps faulty) recollection is that a small amount of pressure has been shown to actually be somewhat beneficial to yeast performance (perhaps reproduction?), but beyond that too much has been shown to be detrimental. I believe this discussion was in regards to commercial conical fermenters, and why their height-to-width ratio should not be too high due to the weight of the wort exerting ever-increasing pressure on the yeast as you go deeper in the tank. I believe this discussion may have been in one of my Belgian style books, but I could be mistaken.

Like many things beer, however, there is theory and then there is practice. I'm curious as to why Don made the conscious decision to ferment under pressure, but he says it works. My question is, what is the benefit?
 

priorm
Junior Member
Username: Priorm

Post Number: 73
Registered: 01-2006
Posted From: 162.44.245.51
Posted on Tuesday, July 01, 2008 - 08:24 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Thanks Graham. I appreciate the effort.

I'm giving the pressurized fermentor setup a try. I've been fermenting primarily in carboys for about 15 years and have had good success. But my 10 gallons kegs were sitting around not being used and my curiosity got the best of me. I was speaking to someone who was fermenting in a 10 gallon corny and thought I'd give it a try. After all, I'm an endlessly experimenting homebrewer! Hopefully, the benefit is better sanitation, better beer and simpler, safer system. Naturally, all of these items are debatable, but if there is something out there that says fermenting under pressure has detrimental effects A, B and C, I would like to know about it.

Better, simpler, more sanitary and safer... OK, here goes. For my setup, cleaning kegs is easier than then cleaning carboys. Kegs don't break as easily as carboys. Kegs block light. For me, I can sample from a keg easier than from a carboy. I can naturally carbonate my beer during fermentation instead of post fermentation. I can transfer my beer under pressure never exposing it to oxygen.

These are some of the benefits that I am hoping for. For now, it's my virgin run, so all this is theory and not practice.
 

Vance Barnes
Senior Member
Username: Vancebarnes

Post Number: 3281
Registered: 03-2003
Posted From: 74.7.7.66
Posted on Tuesday, July 01, 2008 - 09:11 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I'm not sure I follow exactly what you're doing. Has the keg been sealed the entire fermentation? Or are you just now sealing it at 1.021? The last is pretty normal for breweries to seal at ??P to get natural carbonation.
 

Paul Erbe
Senior Member
Username: Perbe

Post Number: 1145
Registered: 05-2001
Posted From: 64.233.251.195
Posted on Tuesday, July 01, 2008 - 09:24 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Yes because force carbonation is frowned upon in Germany(unless they use co2 recovered from the fermentation) it is quite normal for the brewery to seal the fermentors to produce natural carbonation.
 

Paul Erbe
Senior Member
Username: Perbe

Post Number: 1146
Registered: 05-2001
Posted From: 64.233.251.195
Posted on Tuesday, July 01, 2008 - 09:27 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

CARBONATION
The amount of carbon dioxide gas (CO2) that is dissolved in finished beer. The more carbon dioxide is in the beer, the more effervescent it is. Excessive carbonation produces a "burpy," gassy beer. Too little carbonation produces a flat, pallid beer. Carbon dioxide is a natural byproduct of the yeast's fermentation. In a normal wort, yeast produces more carbon dioxide than is needed for the finished beer. At the beginning of fermentation, therefore, carbon dioxide is allowed to escape the fermenter. At the end of fermentation, brewers often "cap" (that is, close) the fermenter to develop pressure in the beer tank and keep the remaining carbon dioxide dissolved in the beer. In German, such "capped" beers are called "gespundet." Un-pressurized beers, similar to British cask-conditioned ales, are called "ungespundet."
 

Paul Erbe
Senior Member
Username: Perbe

Post Number: 1147
Registered: 05-2001
Posted From: 64.233.251.195
Posted on Tuesday, July 01, 2008 - 09:29 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

If I wanted to ferment in a corny I would remove the poppet from the gas in valve and attach a blowoff tube.
 

priorm
Junior Member
Username: Priorm

Post Number: 74
Registered: 01-2006
Posted From: 96.245.18.31
Posted on Tuesday, July 01, 2008 - 09:36 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Yes - I'm just capping the fermenter prior to full attenuation (at 1.021). The keg has not been sealed the entire fermentation; it was vented originally. Not sure where any effects would begin to impact the beer. An ale at 70F takes about 30 PSI to reach an equilibrium of 2.6 volumes of CO2.
 

Don Lund
Member
Username: Donlund

Post Number: 105
Registered: 10-2003
Posted From: 71.163.230.24
Posted on Tuesday, July 01, 2008 - 10:58 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Priorm -- No, I don't repitch. Why do you you ask -- am I missing something?

Graham -- Benefits? I'm old and brewing on a retirement budget, so am trying to keep things cheap and simple by recycling my CO2 - I store it in a junked hot water heater tank, use it for dispensing and counterpressure filling of kegs. Whenever I start running low on CO2, I'll top off the tank to 35 psi or so, using "yeast pressure" (no pump). I carbonate each batch somewhat like priom talks about, even if I don't save CO2 from that batch.

The other benefit is that after I pitch, the beer is closed to the outside world until I pour my first pint. Nice clean process.
 

priorm
Junior Member
Username: Priorm

Post Number: 75
Registered: 01-2006
Posted From: 96.245.18.31
Posted on Tuesday, July 01, 2008 - 11:15 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Don,

I'm asking about repitching yeast because I do. I was curious if you observed any changes in the yeast performance after fermenting under pressure and then reusing it.
 

Don Lund
Member
Username: Donlund

Post Number: 106
Registered: 10-2003
Posted From: 71.163.230.24
Posted on Wednesday, July 02, 2008 - 12:08 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

priorm --

OK, I'm slow but now understand your question. I use dry yeast, don't try to save it. But given the normal way that the yeast seems to react to some pressure, I wouldn't worry about it. Shoot, give it a try...