FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
Re: Oxygenation ... ("steve.alexander")
Re: Water (Jeff Renner)
Merry Christmas! ("Pat Babcock")
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Date: Wed, 24 Dec 2008 04:26:02 -0500
From: "steve.alexander" <-s at roadrunner.com>
Subject: Re: Oxygenation ...
David Kudrav asks
> Recent discussions have raised the following questions in my mind:
>
> 1. I've never gone out of my way to oxygenate, other than using a funnel
> with a filter after cooling the wort to transfer from my boil pot to my
> fermenter (filter and funnel to remove hops and debris from bottom of boil
> pot). But I've never noticed any type of problem with my beer without
> forced oxygenation. Should I force oxygenate, with a stone & gas
> tank?--what difference would I notice in my beer? Other people have had
> my beers and like them (ie, no obvious problems with most batches).
>
First I'll suggest you oxygenate with air as a starting point. Many
methods have been suggested. pouring wort between buckets, pumping
filtered air with an aquarium pump, beating with a whisk, shaking
carboys vigorously.
Yeast require oxygen to make unsaturated fatty acids and sterols for
their cell membranes. When it is lacking you'll have more migration of
"things" across the cell membranes interior and exterior to the cell.
The cells will operate far less efficiently and ultimately the lack of
air (or UFAs and sterol) can be the reason yeast growth stops and
greatly reduces the rate of fermentation (stuck fermentation).
If you add some oxygen you'll generally end up with less fusels and
esters, a faster fermentation and less yeast flavor in the beer. You
may possibly get a little better attenuation, particularly in hi-grav
beers. The final cells in the bottom will be in much better health if
you repitch.
> 2. What of olive oil as substitute for oxygenation? I've read an article
> or two about this, but am not sure I'm convinced of it. Is the chemistry
> sound, or is it bunk? Does anyone use this method? What are the results
>
The biochemistry is not nonsense but the common practice is bunk.
Veggie oil is a combination of glycerices with various levels of
desaturation. Yeast can uptake the olive oil, and this may reduce the
oxygen required. The amount suggested in brewing forums is ridiculously
low; by a factor of 100 or more. If you look through this forum's
archives you'll see I once did a calculation and the amount of OO needed
is on the order of an ounce per 5 gallons of wort (well 20ml). The
problems are considerable. Yeast should be able to consume large
quantities of such oil, but if the yeast fail to clear all the olive oil
then it will kill head terribly. Phospholipids in wort *may* help
disperse the oils, but most likely you'll end up with an oil-slick on
top. Perhaps lecithin would help emulsify the oil. Fred Johnson
suggested salts of fatty acids (soap); but in either case care must be
taken to not disrupt the yeast cell membranes. In the lab they use
Tween80 - an oleic acid compound which is very soluble in water.
Oil additions will greatly reduce the ester level in beer and may not be
appropriate for estery ales.
The other problem not addressed is that yeast require oxygen to make
sterol from squalene. Olive Oil can't supply enough sterol to help so
you still could use some oxygen.
If you want to experiment I'll suggest you try an olive oil addition to
a starter. Actually other oils (perhaps flax) would have less negative
flavor impact and higher desaturation levels.
-S
------------------------------
Date: Wed, 24 Dec 2008 08:45:32 -0500
From: Jeff Renner <jsrenner at umich.edu>
Subject: Re: Water
"Keith Christian" <keithchristian at roadrunner.com> wrote:
> My Anaheim CA water is unbelievably hard. When sanitizing, I have
> been
> using RO water with StarSan. I want to use my tap water that has gone
> through the water softener instead. Will that work alright? I want to
> stop using the RO water for sanitizing.
If your water has temporary hardness, i.e., it contains bicarbonate
ions rather than sulfate ions, then your softened water will still
have a high level of alkalinity.
This means that StarSan made up with softened water will still
sanitize, but it won't keep long.
StarSan is effective as long as it is clear (and of proper
concentration, of course). It will go cloudy if the pH rises too high.
It's not hardness (calcium and magnesium ions) per se that causes
StarSan to go cloudy and ineffective, but the alkalinity from the
bicarbonate ions typically associated with the calcium and magnesium.
A water softener does not affect the alkalinity of water. It
substitutes sodium ions for calcium and magnesium ions. It doe not
change the anions associated with the sodium and magnesium.
RO water is cheap enough that I use it to make up StarSan and it
keeps for weeks.
Jeff
- ---
Jeff Renner in Ann Arbor, Michigan USA, jsrenner at umich.edu
"One never knows, do one?" Fats Waller, American Musician, 1904-1943
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Date: Wed, 24 Dec 2008 10:44:47 -0500 (EST)
From: "Pat Babcock" <pbabcock at hbd.org>
Subject: Merry Christmas!
Greetings, Beerlings! Take me to your Rennerian Eggnog...
Wishing all a safe and merry Christmas. Please be careful out there and
savor the flavor responsibly. Hope all your Christmas wishes come true!
- --
See ya!
Pat Babcock in SE Michigan
Chief of HBD Janitorial Services
http://hbd.org
pbabcock at hbd.org
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End of HOMEBREW Digest #5476, 12/24/08
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