Of wil je bedoelen dat alle cylindro-konische tanks gesloten zijn en onder druk staan?
Sorry als het je verveelt maar ik vond het interessant.
Ik dacht inderdaad dat in die tanks altijd iets overdruk aanwezig is.
En nee, het verveelt mij niet, maar ik denk wel "wat haal je je op de hals".
Op het Amerikaanse forum HBD werd de vraag in 2001 ook gesteld. En er stonden wat reacties. Zie hieronder (in 't Engels, ik had geen tijd/zin het te vertalen.
Hans
Date: Mon, 28 May 2001 19:08:49 +1200
From: "Keith Menefy" <kmenefy at ihug.co.nz>
Subject: Pressure Fermenting
I seem to remember reading somewhere that pressure fermenting helped improve
lagers. (Can't find where I read it). Just changed my system to be able to
do this. I am using a blow off tube into 18 inches of water. Thought that
would increase the pressure quite a bit but on looking it up find that it is
around half a pound/sq.in. Hardly seems worth the trouble.
1. Does anyone know if pressure fermenting really works?
2. What sort of pressure is required?
3. Is there a easier way to get an increase in pressure in the fermentor?
Cheers, Keith, New Zealand
van HOMEBREW Digest #3646 Wed 30 May 2001
Date: Tue, 29 May 2001 08:47:39 -0400
From: Jim Adwell <jim at jimala.com>
Subject: re:Pressure Fermenting
Keith Menefy writes:
I seem to remember reading somewhere that pressure fermenting helped improve lagers. (Can't find where I read it). Just changed my system to be able to do this. I am using a blow off tube into 18 inches of water. Thought that would increase the pressure quite a bit but on looking it up find that it is around half a pound/sq.in. Hardly seems worth the trouble.
1. Does anyone know if pressure fermenting really works?
2. What sort of pressure is required?
3. Is there a easier way to get an increase in pressure in the fermentor?
Well, there is a US patent, 4068005, which claims:
A method of accelerating the fermentation of a lager-type beer comprises
conducting the fermentation at an elevated temperature with or without
exogenous agitation while maintaining the dissolved carbon dioxide
concentration in the fermentation liquor at a level approximating that
found in a fermentation liquor during a normal supersaturated lager-type
bottom-fermentation. The level of dissolved carbon dioxide is maintained
at about 1.5 to about 2.0 cc per cc of beer by use of an overpressure of
2-20 psig of carbon dioxide.
The idea being that one can ferment one's beer at a higher temperature for
less time, thus saving on refrigerating costs and moving the product out
the door faster, which would be important to a mega-brewer like Millers,
Of interest to homebrewers, I suppose, is that this method will cut down on
fusel oils, esters and other nasty things during the ferment, thus making a
cleaner tasting beer. I haven't experimented with pressurized
fermentation, and probably won't. If you are going to try it, DO NOT try
to pressurize a glass carboy ; use a cornie or other container designed for
pressure.
The patent goes into more detail about all this. You can find it at:
http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1='4068005'.WKU.&OS=PN/4068005&RS=PN/4
068005
or you can search for 4068005 at:
http://164.195.100.11/netahtml/srchnum.htmCheers, Jim
HOMEBREW Digest #3647 Thu 31 May 2001
Date: Wed, 30 May 2001 21:03:21 -0400
From: "Mike Pensinger" <beermkr at bellatlantic.net>
Subject: Re: Pressure Fermenting
While I was in Split Croatia a few years back I got a tour of the local
brewpub and discovered that he fermented under pressure. He stated that it
sped the process up and allowed fermentation at higher temperatures without
off flavors being produced. I cant remember how much pressure was on the
vessel and it was in Bars which i didnt understand anyway.
Mike Pensinger
beermkr at bellatlantic.net
http://members.bellatlantic.net/~beermkrHOMEBREW Digest #3648 Fri 01 June 2001
Date: Thu, 31 May 2001 10:20:23 -0400
From: AJ <ajdel at mindspring.com>
Subject: Pressure fermenting
RE:
>While I was in Split Croatia a few years back I got a tour of the local
>brewpub and discovered that he fermented under pressure. He stated
that it sped the process up and allowed fermentation at higher temperatures
without off flavors being produced. I cant remember how much pressure was on
the vessel and it was in Bars which i didnt understand anyway<.
Apparently this is done fairly frequently. The idea is that if CO2 molar
concentration can be kept close to what it would be in the more
traditional cold lager fermentation the yeast will behave more or less
as they do in the traditional fermentation but they will do their work
faster because of the higher temperaure. You say the vessel was in the
Bar? (sorry, I can't help it sometimes).
A.J.
Date: Thu, 31 May 2001 18:45:32 -0600
From: "Robert J. Waddell" <rjw at dimensional.com>
Subject: Re: Pressure Fermenting & H:W
"Mike Pensinger" <beermkr at bellatlantic.net> sez:
>Subject: Re: Pressure Fermenting
>While I was in Split Croatia a few years back I got a tour of the local
>brewpub and discovered that he fermented under pressure. He stated that it
>sped the process up and allowed fermentation at higher temperatures without
>off flavors being produced. I cant remember how much pressure was on the
>vessel and it was in Bars which i didnt understand anyway.
So... what I'm wondering is if the "Pressure Fermenting" thread and the
Height/Width threads are related. It seems that there would be some
optimum depth that the pressure would increase the fury of the
fermentation. It also seems that it would be very difficult to observe
with all of the turbulence of the ferment, so multiple sessions at
different pressures would seem to be the way to determine this. Would
there also be a difference in an open fermentation at sea level compared to
one at altitude? I don't have the resources or the knowledge to chase this
line of thought very far, so I'll turn it over to the collective.
RJW
