From the HBD Archive
From: roberts%studguppy@LANL.GOV (Doug Roberts @ Los Alamos National Laboratory)
Subject: Too Much Foam Revisited
Date: 1990-01-09 00:05:32 GMT

> Date: Tue, 2 Jan 90 15:27:43 EST
> From: Pete Soper <>
Pete relates a Three Stooges Keg Foaming Incident, & asks questions
regarding CO2 keg pressure & foam...

Well, I've been kegging for a bour 4 years now, and I think I've begun
to get a feel for what causes the foaming: too much CO2! There have
been three causes for excess CO2 that I have observed:

1. Not allowing the the wort to fully complete it's secondary fermentation,

2. Overpriming

3. Overpressuring the keg.

At one time or another, I've committed each of these fulminating acts!
However, I believe the most insidious cause of foaminess is
over-pressuring the keg, because overpressuring can make its effects
felt slowly over time, resulting in the end of your keg being much
foamier than the beginning. There are several factors which will
affect the CO2 content of the beer in your keg: temperature, pressure,
and the time the CO2 head at the top of your keg is exposed to
the beer. The lower the temperature, the higher the solubility of
CO2 in your beer. The longer you maintain a high (45 psi) head, the
more CO2 will enter the beer.

After numerous hit & miss attempts, I've now found the (for me) ideal
procedure for achieving the desired carbonation for my ales, stouts, &

1. Let the secondary fermentation complete!! This is particularly
difficult for me, being not the most patient person.

2. Prime with _not more than_ 3/4 cup dry malt extract or syrup. I've
found that this will result in a keg pressure of 10 psi (+ or -) and
the right carbonation for my tastes.

3. Maintain the head with a regulator setting of 10 psi.

I believe you ended up with a foamy batch as a result of your 45 psi
forced carbonation campaign, Pete. If you wish to force carbonate your
kegged beer, I'd set the regulator at 10 psi, and hook the CO2 line up
the dispensing side of the keg, as one other poster suggested. This
will allow the CO2 to bubble up through your batch, carbonating it to
the desired level.

BTW: to get a feel for keg carbonation, fill a keg with tap water &
play around with it. When you're done, you've got seltzer!

- --Doug

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