Fermenting Under Pressure

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wobbly

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What are the percieved advantages /benefits (if any) of fermenting the beer under pressure (15psi) as happens with the Kiwi Ssytem (forgotten the name) and the "Onederbrew" currently referenced under the topic "My Plastic Conical"?

I get it that the beer will be naturally carbonated at the finish of the fermentation period. And the pressure may/will assist in dumping the yeast cake out of the bottom of the cone.

Just wondering what other benefits there might be.

Cheers

Wobbly
 

kevin_smevin

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What are the percieved advantages /benefits (if any) of fermenting the beer under pressure (15psi) as happens with the Kiwi Ssytem (forgotten the name) and the "Onederbrew" currently referenced under the topic "My Plastic Conical"?

I get it that the beer will be naturally carbonated at the finish of the fermentation period. And the pressure may/will assist in dumping the yeast cake out of the bottom of the cone.

Just wondering what other benefits there might be.

Cheers

Wobbly
Apart from the whole process being a little quicker, fermenting under pressure also reduces ester and fusel alcohol formation. I'm sure there are other effects but that's what i get off the top of my head.
 

Bribie G

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When I was at Beervana in NZ a couple of years ago I was talking to a brewer who said that fermenting under pressure definitely gives a cleaner lager beer, as most Kiwi mainstreams are. In fact I was heretically impressed with the likes of Export Gold and Tui etc that they drink over there - pretty dismal megaswills but one thing you can say about them is that they are clean clean clean,none of the soapy mouse piss flavour you get in VB or Tooheys New. So what little malt flavour and hop flavour there was actually came through quite firmly.
 

DJR

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When I was at Beervana in NZ a couple of years ago I was talking to a brewer who said that fermenting under pressure definitely gives a cleaner lager beer, as most Kiwi mainstreams are. In fact I was heretically impressed with the likes of Export Gold and Tui etc that they drink over there - pretty dismal megaswills but one thing you can say about them is that they are clean clean clean,none of the soapy mouse piss flavour you get in VB or Tooheys New. So what little malt flavour and hop flavour there was actually came through quite firmly.
The megas ferment under pressure here too, I wonder if the NZ brewers either lager for a bit longer, use less sugar, better yeast, or not such high gravity, or lower temperature
 

Nick JD

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The megas ferment under pressure here too, I wonder if the NZ brewers either lager for a bit longer, use less sugar, better yeast, or not such high gravity, or lower temperature
Which brewery uses Morton Coutts's continuous technique?

 

jyo

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I know 'Dent' on here has been experimenting with this method recently. I'll link him the thread. He seemed pretty happy with his initial results.
 

dent

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Yeah, I've been giving the pressure ferment a go lately. The principle seems to be that CO2 pressure prevents the yeast from generating esters which would otherwise result from the warmer ferment.

I set it up in a 50L keg. I have a coupler connected with cornelius style adapters, with the spunding valve and pressure gauge attached to the gas post.

I brewed a 40L batch of pale lager with 2042 danish lager yeast - I used a whole cake of yeast from a previous non-pressure batch. I fermented at 14 degrees and 18 psi, however I was careful to start the ferment cold, at about 4 degrees on pitching. I do this so as to ensure a minimum of esters while there is not yet any top pressure. The ferment came up to pressure within a day or so, and then I set the temperature to 14 degrees - in this weather I need heating for lagers!

It is pretty amazing how much CO2 is generated when the ferment is going full blast, it is a like a gas leak going on in the fridge.

Anyhow the primary ferment was done in about six days - the beer was halfway carbonated at that pressure and temperature so it is nice for tasting the hydro samples. As advertised, the beer was not at all estery or fruity, there was no acetaldehyde, or diacetyl/VDKs. Good malt character. There was a fair bit of sulfur, which is to be expected with the closed lager ferment. This was pretty full on at day 7 but after another week it had mellowed out a great deal. The sulfur goes away on its own after a while, or you can wash it out with a bit more CO2 if you are in a hurry. It does give the beer a bit of a commercial character.

I actually dispensed 20 litres of this brew at a party that was on only two weeks after brew day, the keg got sucked down pretty quick, it stood well beside beers brewed traditionally.

I can post some pictures of the setup if anyone likes, it is pretty simple.
 

Nick JD

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I fermented under pressure once with a HUGE Belgian that the yeast couldn't quite cope with. I kegged it way before FG to free up the fermenter and it finished ... eventually. I just burped the keg every day.

Was my best dark strong. Poor bugger too months to finish though.
 

dent

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Ok, here are some pictures - pretty simple setup:







This spunding valve will just let the gas out constantly at a more or less regulated level. Others will reach a threshold and then release it. I hooked it up to my CO2 cylinder and tested it with the regulator to see what pressure and adjustment it started leaking at.

I like that with these kegs you can unscrew the spear and valve assembly, and you end up with a 60mm or so threaded entry at the top of the keg - I just fill the wort in through there rather than through the beer-in post, since it is quicker and I have to put the oxygenation stone in there anyhow.

The other part I like as fermenters, is that you can put a bit of water in them, then put the whole thing on the gas burner with the spear assembly loosened -- boil the hell out of it for excellent sanitation.
 

redbeard

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Hi Dent,

how much wort do you ferment in keg ? is it in a fridge / freezer ? Do you use co2 to transfer it to a corny or another 50l ?

cheers
 

dent

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I've been doing 40L batches in 50L kegs. I think if you tried a full batch for the keg volume it would work, but there may be trouble as yeast blowoff will get in the spunding valve and probably screw with the release setpoint.

I transfer the batch to 2 x cornies with CO2 as a closed system - out the fermenter beer-out, in the corny beer post. Best is to start with both ends at the same pressure, with the CO2 supply attached to the supplying keg, then you allow gas to slowly leak from the recieving keg, which will allow beer to flow in.

I do all the fermenting in the fridge, especially as I prefer to have a very cold start to the ferment during the growth phase - 4 degrees is a good starting point, then 6 until the pressure comes up (a day or so), then to 14. You could start at the higher temperature, but I think that would require you to pressurise the keg manually from the start - you'd have to keep the gas on too, as the gas will dissolve in the beer.
 

booargy

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That is how I carb my beers by using it as secondary. May have to try it with the ferment.
IMG_0561.JPG
PRV is SMC AP100-02 from RS components but I can't find it on their site.
 

Nick_D

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Hey Dent, where did you get the adjustable relief valve on your setup? Do you remember a part name etc? I'm building a spunding valve but am struggling to find one of these little adjustable valves. Sorry to post in such an old topic..... If anyone else has any info, I'd really appreciate it, cheers.

Nick
 

wobbly

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OK at the risk of copping a bagging (again) I will offer details on the standard Williamswarn process for pressure fermenting
  • Set the VPRV (spuding valve) to control at 1.5bar (21psi) for both Lagers and Ales - No issues with my brews (I haven't brewed any Belgians or Stouts) but the recommended procedures are the same
  • Fermentation temperatures using dry yeast - Ale 23C for 4 days by which time terminal gravity is achieved PIlsner/Lagers 15C for 3 days followed by 18C for a further 3 days "D" rest - No issues with my beers
  • At terminal gravity cold crash to 1C in one setting from fermentation temp and hold for 12/24 hours so as to drop the yeast out of suspension - No need to set temp to change in small daily increments
  • I have brewed with US-05, Nottingham, W34/70, S23 and SO4 with no noticeable issues with the above temp/pressure/time regimes
  • Following dropping the yeast then I clarify using a Colloidal Silica product at a rate of 2mls per liter over 24/36 hours and then consume
Wobbly
 

siege

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wobbly said:
OK at the risk of copping a bagging (again) I will offer details on the standard Williamswarn process for pressure fermenting
  • Set the VPRV (spuding valve) to control at 1.5bar (21psi) for both Lagers and Ales - No issues with my brews (I haven't brewed any Belgians or Stouts) but the recommended procedures are the same
  • Fermentation temperatures using dry yeast - Ale 23C for 4 days by which time terminal gravity is achieved PIlsner/Lagers 15C for 3 days followed by 18C for a further 3 days "D" rest - No issues with my beers
  • At terminal gravity cold crash to 1C in one setting from fermentation temp and hold for 12/24 hours so as to drop the yeast out of suspension - No need to set temp to change in small daily increments
  • I have brewed with US-05, Nottingham, W34/70, S23 and SO4 with no noticeable issues with the above temp/pressure/time regimes
  • Following dropping the yeast then I clarify using a Colloidal Silica product at a rate of 2mls per liter over 24/36 hours and then consume
Wobbly
How does dry hopping fit into this system?
 

dicko

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ADMIN:

Guys,

Please keep technical topic posts on topic.
 

wobbly

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siege said:
How does dry hopping fit into this system?
Dry hopping can be carried out at/close to the end of fermentation phase as/when the yeast starts to drop out of suspension by removing the sediment bottle, "disposing" of the settled yeast and then adding up to 3g/l of hops to the sediment bottle, adding about 500mils boiling water to the bottle and then stirring the hops to hydrate, then top up the bottle with beer foam and then reattaching the bottle to the WW and opening the butterfly valve.

This last step causes the hop liquid to shoot up into the fermentation chamber and over time it will resettle back into the sediment bottle

Leave the system like this for how ever many days and then remove the hop filled sediment bottle and cold crash and clarify as normal

Cheers

Wobbly
 

Hoffdegg

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Hi Wobbly,

Im really interested in your method as it seems so quick, especially for lagers. I have just finished my lager in the traditional way (2 week at 9 degrees then 4 weeks at 4 degrees to lager) and it's way to long to wait!
I have just ordered myself a kegking pressure fermenter. Looking forward to testing it out...

When you do it your method under pressure, do you get a sulphar taste in the beer?
Do you still have to condition/lager the beer as you normally would have to with a lager?
So it is pretty much ready to drink after 7 days? And it matches up with a lager that has been fermented over 6-8 weeks?
The high pressure doesn't do anything to the yeast and produces a nice clean tasting lager?
Can yoh pitch off the yeast cake after fermenting at thag pressure or does the pressure kill the yeast over time?
Any information you can be given will be very much appreciated...
Hoff
 

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