From the HBD Archive
From: att!iwtio!korz@hplabs.HP.COM
Subject: oxidation
Date: 1989-10-26 19:36:36 GMT

>Dave Sheehy writes:
>While we're on the subject of oxidation, I'd like to discuss Miller's
>contention that the typical 1 - 2" headspace in a bottle of beer has enough
>oxygen present to cause significant oxidation. Miller recommends using a 1/8"
>headspace to prevent this. I'm not sure I believe him or not. I remember
>some discussion a few months ago about headspace. Has anybody experimented
>with a smaller headspace and if so did you notice any differences one way
>or the other?

I would like to contest Miller's contention. I believe that as you
bottle (and your posting noted a particularly intense occurrence of
this phenomenon), some of the CO2 that was produced during fermentation
that has gone into solution in the beer, comes out during racking.
Usually this is due to the fact that as the siphon draws the beer
up above its previous level, a partial vacuum is produced. When you
fill up the bottle, I believe that from the time that you finish
filling the bottle, to the time that you put the can on, a significant
amount of CO2 has bubbled out of the beer and displaced the air
(and thus the oxygen). This is why I've never been in a great hurry
to put the caps on (purposely).

>The last batch of beer I bottled foamed (or fizzed if you will) while I was
>bottling it. It did this so much that I had trouble maintaining the sipon
>in my transfer tubing. If I stopped for any amount of time a big bubble
>would form in the tubing and I'd have to purge it.

Two theories:
1. tubing was not clean or still had some (egad!) soap stuck
to its walls
2. airlock clogged near the end of the fermentation and the
beer became carbonated -- commercial brewers use counterpressure
bottle fillers to prevent foaming as they bottle carbonated beer

Judging from the behavior of the head after bottling, my best
guess is the SOAP.

Al.

P.S. You may be right about the hot wort oxidation - I haven't read
Miller and chem was my worst subject - Papazian doesn't mention
this hot wort oxidation situation.



Back New Search

The posts that comprise the Homebrew Digest Searchable Archive remain the property of their authors.
This search system is copyright © 2008 Scott Alfter; all rights reserved.