Pressurized fermentation.

[Dave70]

Some or the points raised in the surprisingly controversial 'infections' thread about oxygen badness have caused me to have a think about doing something I once thought about doing then couldn't be arsed with, albeit for different reasons, that is, basically attaching a spunding valve to the gas post of your corny and using it as a fermentation vessel.

Like this.

I'm not so much interested in it for the the more traditional reasons to do with ester production, quicker fermentation, self carbonation and reduction of fusel alcohols - though who wouldn't want that - more so when I walked into the garage this morning, I could smell the imperial IPA bubbling away in the brew fridge before I even opened the door. All that delicious aroma just wafting away.
No doubt the the chemistry is more complex than that, but is there any reason or better still, evidence, the think this approach would help preserve flavor?

I faintly recall a post about this eons ago but cant remember by who. probably moved on by now anyway. Or banned.

 

[Yob]

was just talking about this method on the weekend with another forum member saying I needed to read more about it... Nice one Dave, will be watching and waiting for results.

:beerbang:

 

[booargy]

Ive been doing this for about 3 years now. I use an SMC pressure release valve which I got from RS components. http://australia.rs-online.com/web/p/pneumatic-exhaust-relief-valve-function-fittings/7507848/ Been that long since I have fermented without I can't say about flavour or aroma. It is just a better way to ferment.

 

[robbo5253]

How much Headspace do you need to leave? I have the gauge and have been thinking about giving it a go
Cheers
Robbo

 

[DJ_L3ThAL]

Very interesting, I wonder if any chemists/scientists can comment on the back pressure created on the fermentation and any potential stress it could cause on the yeast to do their thing as a potential negative effect of the method? Cos if you're trying to crap out a big AGB and someone's got a cork rammed slightly up there it is more difficult than if the cork was not there :blink: :blink: :blink:

 

[roger mellie]

I did this a few years ago and I have to say really liked the different mouthfeel self carbonation gave. Never used this method to preserve flavour - only ever to self carbonate but a couple of things spring to mind

1. the backpressure valves don't like liquid or carryover getting in them
2. Would only be useful for secondary in my opinion

Has all the flavour been leeched away by then?

RM

 

[booargy]

My prv sits outside the fridge connected to keg with beer line. All my lagers get done under pressure in a 50l keg not much Krau. Ales I ferment in an 80L keg for head space.

 

[Dave70]

Ive been doing this for about 3 years now. I use an SMC pressure release valve which I got from RS components. http://australia.rs-online.com/web/p/pneumatic-exhaust-relief-valve-function-fittings/7507848/ Been that long since I have fermented without I can't say about flavour or aroma. It is just a better way to ferment.

Care to share process start to finish?
It'll just save questions that way.

 

[eamonnfoley]

Some or the points raised in the surprisingly controversial 'infections' thread about oxygen badness have caused me to have a think about doing something I once thought about doing then couldn't be arsed with, albeit for different reasons, that is, basically attaching a spunding valve to the gas post of your corny and using it as a fermentation vessel.

Like this.

I'm not so much interested in it for the the more traditional reasons to do with ester production, quicker fermentation, self carbonation and reduction of fusel alcohols - though who wouldn't want that - more so when I walked into the garage this morning, I could smell the imperial IPA bubbling away in the brew fridge before I even opened the door. All that delicious aroma just wafting away.
No doubt the the chemistry is more complex than that, but is there any reason or better still, evidence, the think this approach would help preserve flavor?

I faintly recall a post about this eons ago but cant remember by who. probably moved on by now anyway. Or banned.

I do something similar for different reasons.

- I use the spunding valve only at the end of primary (last few points of gravity), to carbonate beer naturally. Its the German method
- I use a blowoff tube connected to the gas-in post to deal with limited headspace.
- I don't ferment under pressure. Not interested in brewing carlton draught!
- Oxidation is prevented because you can have a closed transfer from fermenting keg to serving keg (by purging the receiving keg first).

 

[The Gas Man]

I was at a nsw north coast brewery a couple of weeks ago, and noticed that they have their fermenters under co2 pressure.

I think the initial reason was to keep the tank from imploding due to temperature changes, but not sure if there was a quality reason for doing as well.

 

[Online Brewing Supplies]

Mainly all advantages of fermentation under specific pressures. Requires some study to make it work well .
One disadvantage with certain yeast , mainly lager types is the tendency to throw excessive amounts of sulfur bi products.
This can be reduced by allowing yeast to ferment a bit warmer and flush away sulfur smell .
I have just built a pressure vessel for this specific reason (quick, less bi products etc), mine is some what more high tech with electronic sensor and solenoid.
I will drop an image when I have time.
Nev

 

[booargy]

very similar to foles only prv for whole ferment
I pump chilled wort to keg with a shortened spear. oxygenate and pitch yeast or pump onto yeast cake. Attach PRV and set to carbination pressure and ferment as normal. when ready to transfer attach keg and use co2 to push beer to next keg.
I started doing it to free up my gas bottle.
Another thing I have been playing with lately is transfer from kettle to keg with a vacuum pump connected to gas post on ferment keg.

 

[Online Brewing Supplies]

Here is my vessel.
Welded two corny fittings on, one for a temp probe the other for sensor and gas release solenoid.
The original keg spear is for transfers to kegs.
The solenoid is disconnected atm as I am just pressure testing keg at 13psi.
Nev

 

[Westo]

I have been trying to research this with limited luck on the process i wouldnt mind giving it ago as i like the idea of fermenting the beer and then carbonating using the c02 produced from the beer,, anyway if someone can help me with a guide from start to finish on the process it would be much appreciated.

so far i have got:
between 15 - 17ltrs in a Corny keg
let go for 1 - 2 days then attach spunding valve and set to 2psi
raise psi 1 - 2 per day till you reach 10psi

am i on the right track? how do i know when its ready to bump up for carbonating? do i just take a sample wait for it to go flat then take a reading?

also once ready for carbing do you just set to say 13psi and put in firdge at 5deg to achieve 2.5vol?

if anyone can help would be much appreciated

cheers

westo

 

[gordo_t]

I have been trying to research this with limited luck on the process i wouldnt mind giving it ago as i like the idea of fermenting the beer and then carbonating using the c02 produced from the beer,, anyway if someone can help me with a guide from start to finish on the process it would be much appreciated.

so far i have got:
between 15 - 17ltrs in a Corny keg
let go for 1 - 2 days then attach spunding valve and set to 2psi
raise psi 1 - 2 per day till you reach 10psi

am i on the right track? how do i know when its ready to bump up for carbonating? do i just take a sample wait for it to go flat then take a reading?

also once ready for carbing do you just set to say 13psi and put in firdge at 5deg to achieve 2.5vol?

if anyone can help would be much appreciated

cheers

westo

I'm looking into this myself. Found this article a decent starting point http://bubrew.org/pressure-ferment.pdf

 

[Westo]

yeah GTG i saw that one whilst looking around however it doesnt really tell you how to do it ie what psi to ferment at i had another look today and have come across a few more articles that are steering me towards the answers im looking for check out these:

http://www.homebrewtalk.com/f13/closed-system-pressurized-fermentation-technique-44344/

http://www.terifahrendorf.com/Closed-Pressurized-Fermenatation.pdf

if anyone else who has done this can please give a step by step to help out ..

 

[NewtownClown]

I have racked a few English Bitter into the keg 5-6 gravity points before FG is reached and that has produced a nice cask beer level of carb...
Wouldn't be a difficult experiment to keg at various stages before FG (i rekon around 10 points may be the max required). Over carbonated beer is easily remedied.

 

[Liam_snorkel]

I've had a bit of a look through the various pressurised fermentation threads and picked this one as it is the most recent.

Has anyone done this without controlling the pressure? (ie, just seal up the corny keg)

I'm thinking about doing some experiments but don't feel like forking out for a relief valve just yet (or buying one only to have it fill with krausen). The valve on the lid of the corny will let go if it gets dangerously high, so no risk of injury.

Other than overcarbonated beer, what's the worst that could happen? At what pressure does it start to have a noticeable negative effect on fermentation?

My idea was to seal it up until I would expect the krausen to have dropped, then give it a bit of relief so as not to have overcarbed beer. Hopefully harnessing the benefits of pressurised fermentation, without any outlay.

 

[Mr. No-Tip]

I think there's a point of pressure where the yeast have trouble working and stress out. I did a Berliner in
a large keg last year.

The first batch went into secondary in glass and I pitched another batch onto the cake. I had a blowoff during primary and then went to venting the pressure during secondary, which lasted many months.

This wasn't actually an exercise in pressured fermentation - I was trying to vent it - but that was happening nonetheless. I found the resultant beer had a dirty taste that doesn't really line up with common faults, or the first batch. The cake pitch could be to blame or at least a factor, but I think the pressure didn't help.

 

[gordo_t]

I've had a bit of a look through the various pressurised fermentation threads and picked this one as it is the most recent.

Has anyone done this without controlling the pressure? (ie, just seal up the corny keg)

I'm thinking about doing some experiments but don't feel like forking out for a relief valve just yet (or buying one only to have it fill with krausen). The valve on the lid of the corny will let go if it gets dangerously high, so no risk of injury.

Other than overcarbonated beer, what's the worst that could happen? At what pressure does it start to have a noticeable negative effect on fermentation?

My idea was to seal it up until I would expect the krausen to have dropped, then give it a bit of relief so as not to have overcarbed beer. Hopefully harnessing the benefits of pressurised fermentation, without any outlay.

From my research so far once you get over 25 psi the yeast are no good.

Currently trying to search for some sort of Time/Pressure/Temperature schedule myself.

Edit: I should have said it starts to really impact the yeast @ 25 psi