# Pressurized fermentation.



## Dave70 (16/9/13)

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.


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## Yob (16/9/13)

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:


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## booargy (16/9/13)

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.


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## robbo5253 (16/9/13)

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


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## DJ_L3ThAL (16/9/13)

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:


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## roger mellie (16/9/13)

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


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## booargy (16/9/13)

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.


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## Dave70 (16/9/13)

booargy said:


> 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.


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## eamonnfoley (16/9/13)

Dave70 said:


> 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 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).


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## The Gas Man (16/9/13)

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.


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## Online Brewing Supplies (16/9/13)

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


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## booargy (16/9/13)

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.


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## Online Brewing Supplies (16/9/13)

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


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## Westo (24/11/13)

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


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## gordo_t (25/11/13)

Westo said:


> 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
> ...


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


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## Westo (25/11/13)

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 ..


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## NewtownClown (25/11/13)

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.


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## Liam_snorkel (13/1/14)

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.


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## Mr. No-Tip (13/1/14)

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.


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## gordo_t (13/1/14)

Liam_snorkel said:


> 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)
> 
> ...


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


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## wobbly (13/1/14)

Have a lot at this thread where you will find a PDF file on the subject of pressure fermenting and the impact of various pressures as well as impact on Ester and Fusel production etc

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1992.tb01137.x/abstract?globalMessage=0

Cheers

Wobbly


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## Beerisyummy (29/1/14)

And this one!

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2001.tb00083.x/pdf


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## MastersBrewery (5/2/14)

Have we had any further development of experience/ knowledge in this area?


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## Beerisyummy (5/2/14)

I made a lager that I've named "Two bob lager". So named because it was treated like a dirty, two bob thing.

Anyway, it fermented out at 25c with german lager yeast and is still quite drinkable. I've done similar with a glad wrap fermenter and have had much funkier results.
The results I've had so far are anecdotal at best. They still hint towards this being a useful addition to the brew shed.

PS. I'm currently testing my garden tap spunding valve. Once I have it working properly I'll share the parts list.
:beer:


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## Mardoo (5/2/14)

Hey there Dave70, any word on how this is working out for you?


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## gordo_t (5/2/14)

I gave this a whirl the other week for the first time in one of my standard corny kegs and spunding valve.
I did a lager using s-23, fermented @ 15 degree (slowly built up to 12psi, which was the maximum that my valve would allow, i.e. < 5 psi for first few days then increased). Drinking now at 4 weeks, its nothing too special but certainly drinkable, think there are a few fusal alc tastes there. I think on the next attempt i might do it a degree or two lower with slighly more pressure early on.


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## hockadays (6/2/14)

I've tried this and you need to have a good valve for adjusting the pressure. Beware of filling a corny keg up too much and doing it as you can end up with beer in your valve and pressure gauge. Been there! The homebrewtalk talk thread has all the info required. Finding suitable components is the key, but it does work. I have only bunged lagers rather then pressure fermented them so can't comment on this.


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## Dave70 (6/2/14)

Mardoo said:


> Hey there Dave70, any word on how this is working out for you?


If I'm honest, I'd kind of forgotten all about it, so I'm glad the thread got bumped. I've been more concerned with acquiring / building other do dads like stands, a chiller and a great big pot so I can do stuff like pain free step mashes. The old faithful esky has its limitations and is (literally) starting to crack under the strain. 
Look, for a hand full of fittings, a few bucks and ten minutes of your time it's certainly worth having a go as the idea certainly seems to have merit.


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## Beerisyummy (8/2/14)

G_T_G said:


> I gave this a whirl the other week for the first time in one of my standard corny kegs and spunding valve.
> I did a lager using s-23, fermented @ 15 degree (slowly built up to 12psi, which was the maximum that my valve would allow, i.e. < 5 psi for first few days then increased). Drinking now at 4 weeks, its nothing too special but certainly drinkable, think there are a few fusal alc tastes there. I think on the next attempt i might do it a degree or two lower with slighly more pressure early on.


Way more fun in a big keg!

I'm still going on this experiment and will keep posting my results.

The current batch is 5kg prem pils, 0.2kg acid and saaz to suit. This batch will be treated like a princess @ 15psi.

Even if the beer is not any better, the system still offers plenty of benefits for my brewery. It's quicker and cheaper to run for starters.
The downside is that the initial outlay is bigger and the FV is hard to move around.
(Both of these views are based on doing batches for 2x18l kegs).

Happy brewing.


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## wobbly (8/2/14)

Those trying out pressure fermenting might be interested in the "Cornical" about to be marketed by Blichmann. See details in the attached web

Cheers

Wobbly

http://blichmannengineering.com/news/new-product-update


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## Beerisyummy (8/2/14)

wobbly said:


> Those trying out pressure fermenting might be interested in the "Cornical" about to be marketed by Blichmann. See details in the attached web
> 
> Cheers
> 
> ...


Saturday night beer porn!


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## gordo_t (11/2/14)

My adjustable releif valve (same as pictured in the original post) seems to be continually leaking, i.e. i can't hold pressure stable, if I charge to say 5 psi, it slowly leaks to 0 in about an hour).

I checked by dunking in some soapy water and can see it slowly but surely bubbling out the end valve. Tried some keg lube around the seal to see if it slows it at all but no luck.

Are they not designed to hold steady pressure at all, or do i have a dud here?


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## DJ_L3ThAL (17/2/14)

G_T_G said:


> My adjustable releif valve (same as pictured in the original post) seems to be continually leaking, i.e. i can't hold pressure stable, if I charge to say 5 psi, it slowly leaks to 0 in about an hour).
> 
> I checked by dunking in some soapy water and can see it slowly but surely bubbling out the end valve. Tried some keg lube around the seal to see if it slows it at all but no luck.
> 
> Are they not designed to hold steady pressure at all, or do i have a dud here?


An adjustable relief valve, functioning correctly should only vent out at the desired pressure. So it sounds like you have a faulty unit.


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## gordo_t (17/2/14)

DJ_L3ThAL said:


> An adjustable relief valve, functioning correctly should only vent out at the desired pressure. So it sounds like you have a faulty unit.


I managed to get it working at bit better by stretching the spring in the valve ever so slightly. still very touchy though, might have to source a new one.


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## wobbly (24/2/14)

Not sure if this is allowed but anyway

This post on another forum has something like 194 pages of details and info/benefits/process etc on setting up and using 50lt kegs to pressure ferment in which might be of interest to those wanting to go down that road

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

Cheers

Wobbly


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## MastersBrewery (24/2/14)

The yanks are using 15.5 gal kegs so about 58L so a 50l keg posses the problem of reduce head space, in a conical they say to leave or account for 20% head space, so for a double batch its cutting a little close though I guess there's only one way to find out. Of note iBrew just south of brissy I think had some US sanke kegs for sale might be worth checking out. My favourite conical if I could afford to import it would be these, price is awesome but don't know what it would be worth to ship (note they come in under the $1000 so no gst) I know guys have brought in big bilchmans with shipping forwarding companies might be worth checking out.

Oh and the conicals I linked to are leak tested at 100psi so well and truely good to go


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## rehabs_for_quitters (24/2/14)

I am looking at doing 50L kegs into pressurised conicals, I haven't done the math to well but once you add the cone you will increase the volume by around 10 to 15 litres at least so should be with in cooey for head space I would think, and they wold handle the pressure happily


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## dent (24/2/14)

I've been fermenting under pressure the last few years. I've tried a few different relief valves, currently I have settled on these:

Pressure cooker jigger valve

They're very cheap, and have a low hysteresis which I prefer. The thread is close enough to 1/8" BSP you can get it in with a decent amount of thread tape. There is no pressure adjustment - it is only fortunate that the pressure these start to let go is about perfect for fermentation. Most of these and other small PRVs like it leak a tiny amount over time - I find it quite beneficial to put a small valve in series with the PRV so you can use higher pressures for oxygenation and transfers if required, as well as simply sealing it off when fermentation is complete. Obviously never leave it closed at the start of the ferment!

I have also experimented with replacing the spring in the built-in PRV in a corny keg, which works OK - corny kegs are a bit of a pain to sanitise as effectively as a 50L keg - those you can just bung on the gas burner with a bit of water inside, and boil away. You can even put the pressure cooker valve to its intended use if you're feeling brave.


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## Online Brewing Supplies (24/2/14)

dent said:


> I've been fermenting under pressure the last few years. I've tried a few different relief valves, currently I have settled on these:
> 
> Pressure cooker jigger valve
> 
> ...


Mods please remove to Ghetto thread :lol:
Nev


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## mr_wibble (25/2/14)

Beerisyummy said:


> I made a lager that I've named "Two bob lager". So named because it was treated like a dirty, two bob thing.
> Anyway, it fermented out at 25c with german lager yeast and is still quite drinkable. I've done similar with a glad wrap fermenter and have had much funkier results.


So are you saying you had *less* esters in the final beer?

I read something about open fermentation (for wheat beer) the other day. 
The author suggested open fermentation produced more esters, and thus it seems to line up.


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## manticle (25/2/14)

> Not sure if this is allowed but anyway
> 
> This post on another forum


Totally allowed mate. The rule I think you are referring to is about active links IN SIGNATURES to other brewing forums. You can (and should always be allowed to, in my view) post useful links about topic relevant material, whether or not that link goes to discussions on a different forum or not.


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## wobbly (25/2/14)

MastersBrewery said:


> The yanks are using 15.5 gal kegs so about 58L so a 50l keg posses the problem of reduce head space, in a conical they say to leave or account for 20% head space, so for a double batch its cutting a little close though I guess there's only one way to find out.


In the thread I linked to overcome the lack of head space in the 15.5 gallon keg when fermenting close to the keg limit some have linked a standard 19lt keg half filled with water (so as to reduce the head space back to acceptable volume) in series with the fermenting keg and installed the relief valve on the 19lt keg and fermented a large batch (double) that way

Cheers

Wobbly


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## Beerisyummy (25/2/14)

Mr Wibble said:


> So are you saying you had *less* esters in the final beer?
> 
> I read something about open fermentation (for wheat beer) the other day.
> The author suggested open fermentation produced more esters, and thus it seems to line up.


Yes, I would say there were less esters in the final beer. It was still drinkable, although I'd not make a habit of that particular process.

In regards to the open fermenters, there are so many variables it's not funny. My take on most things I've read is that the FV design will impact on the way the yeast does it's thing.
I'd imagine that an open fermenter, with a good amount of surface area, would keep the amount of dissolved C02 (in solution) down. That should help the yeast go crazy, and create plenty of funk.
Alternatively, you could also up the temperature a little for a similar result.

Pressurized fermentation is just another way to manipulate the way the yeast behaves. It won't stop you needing to age a beer or fix other problems.
The carbonation and transfer part of the setup is the winner for me.


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## Not For Horses (26/2/14)

Was reading this little article
http://www.professorbeer.com/articles/esters.html
and came across the following:

" 3. Fermenting under pressure, as some lager brewers do, will decrease esters by decreasing the rate of yeast growth, thus decreasing the fusel precursors."


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## MastersBrewery (26/2/14)

NFH I think the polar opposite is higher ferment temperatures, thus balancing pressure v temperature. I don't think it's going to be a case of one set of parameters fits all, it may well be the case that each strain will have it's own "sweet spot" while parameters for ales may all group similarly as apposed to those for lagers.


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## Not For Horses (26/2/14)

Reading on from there he says that most home brewers and craft brewers lack the equipment to ferment under pressure.
So I think he actually meant *l**arger* brewers rather than *lager*.


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## dent (26/2/14)

> will decrease esters by decreasing the rate of yeast growth


I don't think this is correct. Yeast do not start generating large amounts of CO2 until after the growth phase, thus, no pressure at the growth stage. 

Plus I start all my pressure ferments very cold to avoid the yeast growth generated off-flavours. Only once the CO2 pressure starts to come up do I ramp up the temperature and get it the ferment going full bore.


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## Not For Horses (26/2/14)

There's pressure at the growth stage if you pressurise your FV when you pitch.

But I don't think he has the whole story anyway.


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## dent (26/2/14)

Yeah but I don't think it is why the pressure ferment works, so it would be pointless. I use that time to pressurise the vessel with oxygen anyhow.


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## Liam_snorkel (26/2/14)

pointing out the obvious here, but large scale brews would be under head pressure from the start due to the volume of liquid above the (bottom fermenting) lager yeast.


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## dent (26/2/14)

Head pressure, sure, but the quantity of dissolved CO2 in the wort would not be increased as a result. 

I'm making the assumption here that the dissolved CO2 interacting with the yeast is what makes the pressure ferment effective - I've yet to hear anything that would say otherwise.


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## Not For Horses (26/2/14)

True, but it doesn't account for reduced ester production with an ale yeast.


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## Liam_snorkel (26/2/14)

this is where we need a microbiologist to step in and tell us what the effect of hydrostatic pressure is on yeast regardless of CO2 content.


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## gordo_t (26/2/14)

dent said:


> Yeah but I don't think it is why the pressure ferment works, so it would be pointless. I use that time to pressurise the vessel with oxygen anyhow.


How much pressure are you using (with oxygen) initially??


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## Not For Horses (26/2/14)

dent said:


> dissolved CO2 interacting with the...


Hmmmm. Now this has got me thinking about carbonic acid.
And the hydrolysis of esters.
And how esterase will be affected by the presence of a weak acid.

Much beard stroking and head scratching to be done now...


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## dent (26/2/14)

CO2 interaction makes sense to me as it is a waste product of the yeast after all. I would guess changing the concentration in the wort makes a difference to cell wall transports etc.


With pure O2 I was putting in about 15-20psi, with air about 40psi. The increased pressure allows me to get much more dissolved oxygen than you would otherwise obtain with atmospheric air. I don't bother with air stones, I just shake the vessel upfor a bit while it is pressurized. I'm quite sure this gets me up to the ideal dissolved O2 range.


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## gordo_t (26/2/14)

so are you using something similar to the keg chargers (co2) but switching it out for an oxygen canister instead, like one of the welding ones?


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## dent (26/2/14)

Yeah, just a gas disconnect which attaches to either the regulated O2 cylinder, or the compressor. 

Pure O2 is completely unnecessary in this configuration in my opinion, and I'll be bringing my cylinder back to BOC soon as I get around to it.


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## Beerisyummy (26/2/14)

dent said:


> I don't think this is correct. Yeast do not start generating large amounts of CO2 until after the growth phase, thus, no pressure at the growth stage.
> 
> Plus I start all my pressure ferments very cold to avoid the yeast growth generated off-flavours. Only once the CO2 pressure starts to come up do I ramp up the temperature and get it the ferment going full bore.


Depending on how you pitch, I don't think pressure( on our gauges) always equals the effect of co2 in solution. The lag phase will always overlap the growth phase.
I know you're not saying it doesn't, but I'm thinking that a fair amount of CO2 gets absorbed in the still liquid, which does come into play early on.


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## dent (26/2/14)

Yeah, but if there is no increase in pressure, how is it different from normal open fermentation at that point in time? CO2 will be in saturation at that point either way.


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## Beerisyummy (26/2/14)

That's a good point!

I don't believe that most of our pressure gauges read very well at low pressures. I do believe that all the batches I've tried have started building pressure immediately after pitching an active starter.

Thanks for posting all the other info about your process Dent. Good stuff.


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## Mardoo (26/2/14)

Regarding ester formation and brewing under pressure don't forget to read the papers in the links from posts 21 and 22. They're very clear about the relationship between ester formation and yeast growth under pressure. Thanks wobbly and beerisyummy for those great links!


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## Not For Horses (27/2/14)

Seems that pressure has no impact on fusel production so the increase in temp also means an increase in total fusels.
Sounds like headache material but I'd be interested in hearing if any of you guys had noticed this.


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## dent (27/2/14)

I haven't noticed any. Not saying it can't happen though - I only run the temperature up to 14 degrees for lager yeast, and 20 for ales. I have done a few 9% beers under pressure and they were very smooth/drinkable alcohol wise - it is pretty obvious when the big beers start getting unpleasantly boozy.


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## wobbly (5/3/14)

For those experiencing issues with sourcing a functioning "spunding valve" these details of a "home made unit" may be of some assistance http://www.homebrewtalk.com/f51/spunding-valve-commericial-style-diy-333907/

Cheers

Wobbly


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## Beerisyummy (6/3/14)

wobbly said:


> For those experiencing issues with sourcing a functioning "spunding valve" these details of a "home made unit" may be of some assistance http://www.homebrewtalk.com/f51/spunding-valve-commericial-style-diy-333907/
> 
> Cheers
> 
> Wobbly


Nice link Wobbly. I can't believe I missed that one in my searches.

Tomorrow I'll try to get another test batch on in the keg fermenter. This time I'll take some photos of my garden tap spunding valve.
The next batch is going to be a kit beer, just to see if they still taste like crap. h34r:


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## dent (8/3/14)

El cheapo PRV at work


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## Rambo (8/3/14)

Thinking of doing something similar, though in a corny keg. Does the pressure reduce the size of the krausen, and therefore the head space needed?


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## roger mellie (8/3/14)

Rambo said:


> Thinking of doing something similar, though in a corny keg. Does the pressure reduce the size of the krausen, and therefore the head space needed?


It appears so Rambo - I am up to my 3rd pressurised brew and the Krausen appears to be less. I am doing a 1.076 IPA at the moment and from what I can see its not trying to climb out of the fermenter - yet.

I haven't read all of this thread - but all I would say is that I wouldn't be relying on a spunding valve for all of the pressure relief. I would have thought it imperative to have a separate control and pressure relief valve.

RM


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## rehabs_for_quitters (8/3/14)

Why do you think you would require a seperate PRV to the spunding valve, surely theres not that much pressure to relieve?


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## Online Brewing Supplies (8/3/14)

If at all worried about krausen the just add some anti foam , used in the right proportions it will not affect the brew negatively.
Nev


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## Beerisyummy (8/3/14)

From what I've read around the traps, the pressures can get pretty high. 60+psi.

It can't hurt to have a backup.


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## dent (8/3/14)

I avoid going over 40L in a 50L keg. Getting krausen in your PRV is pretty annoying - it also will dry up, get sticky, and completely upset the calibration - it can even seal itself shut which is bad for obvious reasons.


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## roger mellie (8/3/14)

From the reading I have done - the amount of CO2 produced during a normal ferment is 10+ times the amount needed for carbonation.

Thats a high volume of gas to get rid of. I know I could easily exceed 3 Bar in my fermenter - that has a 3 bar PRV as a safety.

I work in an industry where putting eggs in one basket is considered a no no. Most pressured tanks have 3 safety devices - 2 PRV's and a bursting disk. I would consider putting all faith in a spunding valve - that could pretty easily get clogged with krausen (if the vessel wasn't big enough for instance) is risky


Thats all


RM


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## roger mellie (8/3/14)

Gryphon Brewing said:


> If at all worried about krausen the just add some anti foam , used in the right proportions it will not affect the brew negatively.
> Nev


Nev - no downstream effect on head retention?

RM


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## MastersBrewery (8/3/14)

I think Nev was refering to ferm cap, and it has no residual effect on head retention


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## Online Brewing Supplies (9/3/14)

roger mellie said:


> Nev - no downstream effect on head retention?
> 
> RM


Not that I have noticed.
Nev


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## Beerisyummy (9/3/14)

roger mellie said:


> From the reading I have done - the amount of CO2 produced during a normal ferment is 10+ times the amount needed for carbonation.
> 
> Thats a high volume of gas to get rid of. I know I could easily exceed 3 Bar in my fermenter - that has a 3 bar PRV as a safety.
> 
> ...


Hey RM,
From the reading I've been doing, the yeast will cease to make CO2 beyond a certain point. From memory, the figure is around the 35psi mark.
My personal experience is that it's not that hard to get 35 psi (2.4bar) at room temp. Beyond that, I'd imagine you'd have to tweak the temperature and other variables.

Of course, none of this takes into account all the horrible things that commonly go wrong while making accidental bottle bombs. The usual infections from wild yeasts and bacteria could easily occur in a pressure rated fermenter, and I couldn't agree more with you about the back up PRV.
With an infection I'd imagine >4bar is very possible.
My fermenter has a corny lid fitted for easy access and the back up PVR. Add to that the valve on the keg coupler and you've got tripel redundancy.

While on the subject of spunding valve blockages, I thought I'd finally post a shot of my garden tap valve. Easily the cheapest and least likely to block valve.


She's done three brews now with minor problems along the way, but the valve itself is pretty sound. The main adjustments I've tried are the spring and washer types.
The best combination I've found is the spring out of a regular trigger sprayer (windex, spray and wipe, whatever is going at the time) and the Fixatap Leaklock valves. http://www.fixatap.com.au/cat/tap-valves#prettyPhoto[pp_gal24]/0/

The rest of the assembly is still in development at the moment, but it's got the usual pressure gauge and disconnects. The main add on I use is an airlock that lets me see how much gas is being released.
I find the airlock allows you to make very small adjustments while the pressure is ramping up. It also lets you see the low pressure release that doesn't show up on your gauge.

I hope someone finds this option useful. It has to be the easiest valve to dismantle and clean.
Cheers.

Edit:
The white washer that sits between the tap head and the body is just a silicone jobby from Craftbrewer. Using one means you don't need a spanner to undo the rig.


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## Beerisyummy (10/3/14)

dent said:


> El cheapo PRV at work


I won't ask about the soldering job. h34r:

Would you mind posting the parts list?

A good source of pressure gauges, in the right range, is pool filters. You can buy them new at many places, or just keep an eye out during council clean ups.


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## dent (10/3/14)

Here you go

1/2" to 1/4" bush (the part so artfully soldered to the keg)
1/4" Y adapter (one male end, two female ends)
1/4" to 1/8" bush (for the gauge)
gauge
1/4" male to 1/4" female ball valve
1/4" to 1/8" bush
China's finest cheapest pressure cooker jigger valve


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## dent (10/3/14)

Beerisyummy said:


> A good source of pressure gauges, in the right range, is pool filters. You can buy them new at many places, or just keep an eye out during council clean ups.


Yeah not bad http://www.ebay.com.au/itm//140451021261


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## mb-squared (25/3/14)

Has anyone tried the spunding valve from kegking yet? page 38 here: http://kegking.com.au/Downloads/Catalogue%20-%20Retail%20Price%20List.pdf only $30 and it comes with a gauge too. seems pretty reasonable, but I fear it will fall apart the first time it's used. anyone have any experience with them?

cheers,


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## gordo_t (27/3/14)

mb-squared said:


> Has anyone tried the spunding valve from kegking yet? page 38 here: http://kegking.com.au/Downloads/Catalogue%20-%20Retail%20Price%20List.pdf only $30 and it comes with a gauge too. seems pretty reasonable, but I fear it will fall apart the first time it's used. anyone have any experience with them?
> 
> cheers,


It looks identical to the one i'm currently using. Works fine, though only gripe is that the gauge and valve are only for 15psi/100Kpa, think CB where selling one with a 30psi gauge which would be more useful when building up pressure at the end to carbonate.


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## mb-squared (27/3/14)

Thanks for that GTG. Good to hear yours hasn't fallen apart on you. 

Can I ask why you'd want more than 15psi? My calculator tells me that if I want 2.2 volumes of CO2 at 4C, I need 8.6psi. This is pretty normal for me as I brew mostly ales. For lagers, I like 2.7 volumes of CO2 (at the same 4C temp), which equates to 14psi, so the upper end of the valve's ability I guess. But when do you need more than 15psi? 

Thanks for info. I'm not opposed to spending more for the CB one if it makes sense to go that route.

Cheers,

matto


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## dent (27/3/14)

While 15 psi at those cold temperatures would be adequate, when you're fermenting, it is much warmer, and rather less CO2 stays in solution. When it gets to be time for chilling the fermenter, no more CO2 is being generated. So when you chill it, the dissolved CO2 stays the same (not quite enough) and the pressure goes down due to the change of temperature.


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## rehabs_for_quitters (27/3/14)

Dent I've had quite a few 6% saisons and I just can't seem to formulate how to ask the question I would like answered, but here we go anyway hope it makes sense 

I was thinking set at a pressure and forget until ferment is done then transfer and hold in a bright tank to age before transferring under pressure again to serving vessel,

So after that the question actually is what sort of pressures are you using and roughly at what temps per style to get them close to serving pressure are you going with, or are you still adding carbonation after the ferment


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## mb-squared (27/3/14)

ah, right, of course. geeze I'm really dumb sometimes. thanks for setting me straight!


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## dent (27/3/14)

Well, with 15 psi at 14 degrees or so you still end up with about 2 volumes of CO2, which isn't terrible. For an ale that ends up at about 1.8 volumes at 18 degrees. 

If I'm in a hurry I'll force in bit more high pressure CO2 post ferment, but if, after transfer, you put the keg at your serving pressure for a week or so it will get up to your desired carbonation on its own reliably enough. So it isn't a big deal, you're most of the way there already.


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## Florian (27/3/14)

Also keep in mind apparently you're only meant to use a gauge up to about 2/3 of it's highest pressure or else they might get damaged. This was at least repeated numerous times on here a couple of years ago. True or not I stick with it, my spunding valve goes up to 400 kPa.


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## mb-squared (27/3/14)

Florian said:


> my spunding valve goes up to 400 kPa.


that sounds good. is this one you've made yourself? or is it an off-the-shelf job? if so, care to share where you got it? 

I currently use 50L SS kegs as my fermenters, but just with an airlock. I'd like to move to a set up where I can finish the fermentation under pressure and where I can do closed transfers into my secondary (also a 50L keg).

cheers,


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## rehabs_for_quitters (27/3/14)

I am currently converting some 50L kegs into conicals to pressure ferment, and was going to make a couple extra to use as bright tanks so this info is all good, cheers for the advice


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## Florian (28/3/14)

mb-squared said:


> that sounds good. is this one you've made yourself? or is it an off-the-shelf job? if so, care to share where you got it?


I bought mine from craftbrewer a few years ago, I think it was one of the first ones. When I received it it came only with a 100 kPa gauge which is obviously pretty useless, so I sourced the 400 kPa gauge myself and got reimbursed from Ross for it.

EDIT: the gauge was around $20ish from memory, so there is always the option to replace the one you have.


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## find_another_slave (3/3/17)

This popped onto my radar the other day - mentioned earlier in this thread, but more as a "stay tuned". Apologies if repeated elsewhere.

http://www.blichmannengineering.com/products/cornical


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## malt junkie (3/3/17)

US$500 to ferment a single batch(before shipping) sorry Blichmann ain't getting my money.


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## DJ_L3ThAL (4/3/17)

Fair bit of non material cost in producing a pressure vessel and having it approved in various countries. To get AS1210/AS3788 approval which I assume it may need to be sold here will require engineering and design time so that will up the cost and hinder mind sets if we look at the cost to build purely from a materials perspective. To get Aus approvals for such a relatively small market is also an obstacle for the creators I'm sure.

I guess thats the concsious decision SS Brewtech made to hit a price point. If you want true pressure ferments I think you need to prepare to fork out in the step change cost bracket. I hope I'm wrong but have already mentally prepared myself you never be able to pressure ferment in a SS conical.


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## DJ_L3ThAL (4/3/17)

Also just watched the video. Ine thing I've noticed with my chronical is that the SS walls provide a much more "clingy" surface for the yeast to hang on to and the walls are covered in yeast all the way from ber surface to the trub cone at the bottom (my plastic FVs never did this).

So for this being tipped over and changed to a keg I'm guessing that there would be a minimal amount of yeast stirred back into solution once turned back over that would need to settle, which may be an annoying little bug with the setup that annoys those who've paid top dollar kowing theres yeast stuck all over your keg walls that will get stirred in each time you move the keg potetially more so than when you just have a bit at the base of the keg ...


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