This is where it all started for the home brewer, has been taken out of context since though.
Closed System Pressurized Fermentation
by Teri Fahrendorf
Copyright 1992-2010 by the Author
You have the Author’s permission to distribute this article, as long as her name remains attached.
The best home brewing system is the simplest to use. The less complicated your technique, the
more you can concentrate on the joy of the art of home brewing. Many homebrewers spend more
time brewing one batch of beer than a professional microbrewer would per batch. And they worry
about their beer more (and they should be relaxing) because their equipment is jerry-rigged, not
sanitary by design, or is not easy to work with.
After I began to brew professionally in 1989, I began to think about how some of the fermentation
techniques used in a microbrewery could be adapted for home-brewing use. One of the wonderful
pieces of equipment in the brewpubs that I have worked for, are the pressurized fermentation tanks.
Once fermentation has begun, the system is "closed" from that point forward; the beer is never
exposed to the air again until it is served into your glass. The tank can be held under pressure, so
that the beer is naturally carbonated from the primary fermentation.
The advantages to this system are that you no longer need to prime, rack, or bottle the beer, or clean
bottles and the beer is ready to drink sooner!
Fermentation at Steelhead Brewery
The wort from our kettle is chilled to yeast pitching temperature and transferred to a fermenter and
then the yeast is pitched. As fermentation begins, the CO2 created is allowed to escape out of a hose
attached to the top of the fermenter with the other end in a bucket of bleach water. This is essentially
an air lock. (A fermenting beer creates much more CO2 than that which is needed to carbonate the
beer.) As the beer ferments, the gravity is falling in direct proportion to the amount of alcohol being
produced. When the gravity has fallen almost all the way to the beer's predicted final gravity
(usually two to three days after pitching), the hose is removed and a pressure-relief device and a PSI
gauge are attached instead. The CO2 produced by any further fermentation is trapped, and this
becomes the natural carbonation and head on the beer. The pressure will build to about 15 to 18 PSI.
No need to prime the beer with more wort or corn sugar, and the beer has been sealed in a closed
system.
Because we have no secondary fermenters or conditioning tanks, the beer is conditioned in the
fermenters for another week or two. At that point the beer is chilled to near freezing temperatures.
Chilling forces most of the yeast to fall or flocculate out. After being chilled for 1 to 2 days, the beer
is filtered and transferred (still under pressure) to a serving vessel, where it is tapped. This transfer is
done via a closed system and the beer is not exposed to the atmosphere. The total elapsed time from
brew day to drinking day is about 10 to 14 days. Darker and more alcoholic beers may take 3 to 4 weeks
Search on Google for the full text as she explains how the home brewer can build a system.
