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HOMEBREW Digest #5192
HOMEBREW Digest #5192 Thu 07 June 2007
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
Olive Oil (Jeremy Bergsman)
Re: Olive Oil (Fred L Johnson)
re: Olive Oil ("-s@adelphia.net")
Malt Madness Homebrew Competition ("Al Hazan")
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Date: Thu, 07 Jun 2007 00:35:00 -0400
From: Jeremy Bergsman <jeremy.bergsman at gmail.com>
Subject: Olive Oil
Well, I'm sure -S will chime in on the biochemistry, but if their
biochemistry is as good as their math, I wouldn't take New Belgium's advice
here (unless they are brewing 18 million gallon batches). Maybe they mean
300 microliters....
- --
Jeremy Bergsman
jeremy at bergsman.org
http://bergsman.org
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Date: Thu, 7 Jun 2007 07:11:15 -0400
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: Re: Olive Oil
I would expect that making soap from the olive oil would be a much
better way of providing fatty acids to the yeast (if that is what you
want to do). I doubt yeast have very much if any capacity for
transporting triglycerides into their cells. Perhaps they secrete
triglyceride lipase (or spill their guts at their death), but
hydrolyzing the fatty acids away from the glycerol backbone would still
likely work much better than adding oil.
Fred L Johnson
Apex, North Carolina, USA
------------------------------
Date: Thu, 07 Jun 2007 14:27:50 -0400
From: "-s at adelphia.net" <-s@adelphia.net>
Subject: re: Olive Oil
I'm in the middle of some urgent work so I'll have to make a brief reply
to Matt
Baum's belated discovery that need unsaturated fats made with oxygen.
> "The basic concept is that since yeast uses an oxygen atom to pull a
> hydrogen away from an 18 carbon chain unsaturated fatty acid to make a
> monounsaturated fatty acid chain to help it grow, you could simply
> provide an 18 carbon monounsaturated fatty acid and it would be able to
> use that. This works well in practice, we made a little over 1 million
> bottles with beer where the yeast had had olive oil added.
>
I microbiologist who used to post here long ago [wasn't Liddel - can't
remember the
name] was (as far as I know) the first to cite a report on this to the
HB community.
His reference paper demonstrated that yeast can live anaerobically
(forever, not
just 4 generations) so long as they are supplied with UFA(unsaturated
FAs) and
sterol. I believe that was reposter on HBD circa 1995. Not news.
Charlie Scandrett (who hasn't posted here in ~7 years) reported on a
paper that
described the FA uptake method of yeast. Not news.
...
> the
> amount you actually need is pretty small. Additionally, you want to use
> a very small amount to avoid any detrimental effects that the oil would
> have on the beer's head retention.
>
1/ UFAs are the demons when it comes to head retention. saturated FA
are less
damaging.
2/ The amount is NOT small. Healthy yeast are abt 10% fat by dry mass and
something like 10-20% of this is UFAs (from memory, I'll check later).
> "For the volume of wort we normally ferment, we would pitch about 4500L
> of yeast, and to that we would add around 300mL of olive oil. To
> translate that into a 5 gallon size, you would need to measure about
> 0.0000833mL of olive oil. For any practical purpose, that is much too
> small an amount to accurately measure out. You could fudge and just add
> the tiniest imaginable drop to the yeast you have, but you'd be
> over-dosing the oil by thousands of times the required amount, and run
> the risk of having zero foam retention. Not a good compromise in my
> opinion.
>
That number is way- wrong !
The amount of FA specified here (0.0000833ml) is low by at least 2 orders of
magnitude and I'd wager it's more like 4 ! If you want to supply all
the yeast
FAs by oil addition then you 'd be measuring with teaspoons, not
micropipettes.
> Some thoughts:
>
> First, it's just kind of stunning to hear that this has been done on
> such a large scale.
>
I agree. I've done this on a test scale years ago (1L size) and the
impact is pretty
clear.
> Second "pull a hydrogen away from an 18 carbon chain unsaturated fatty
> acid to make a monounsaturated fatty acid chain" doesn't quite make
> sense to me and is maybe a typo?
>
This is a stupid, tho' accurate statement which emphasizes the wrong issue.
The guy who wrote it was trying to relay a point he didn't really
understand.
All they are saying is that yeast convert oleic(saturated c18) to some
unsaturated
form like linoleic, linolenic ... and use oxygen to do it. C18 FAs are
the most
common in yeast and most plants, but both yeast and olives also contain and
desaturate C16 and C20 and others - just a dumb*ss way of saying yeast need
oxygen to make the UFAs they need.
> Third, this is not entirely new. Olive oil is mostly unsaturated C18
> fatty acids, and it has been known for quite a while that yeast can
> reproduce without oxygen if they are provided linoleic acid (one of the
> olive oil components) and ergosterol.
>
Right - but where are these guys adding the ergosterol (or other
sterols) ? That's
why it's a lousy method. FWIW yeast make and use a set of sterols -
not just
ergosterol. Several isomers of zymosterol are significant in yeast for
example.
I seem to recall sitosterol as well. The cell wall properties vary as
you change the
sterol mix too ! So that save part of the oxygen by adding UFAs but
then they
still need it for sterols.
> Question 1: Okay so what about that ergosterol? Does the linoleic,
> oleic, or anything else in olive oil allow yeast to produce sterols?
No ! There are plant sterols that can be substituted (perhaps at a
performance
cost), but the concentration in plant lipids is too low for yeast unless you
separate & concentrate these.
The other problem is that UFAs & sterols make for better more efficient
yeast
membrane - good thing. But normally *sterol* is the growth limiting factor
in brewery fermentation. In most cases yeast will stall for lack of sterol,
not UFAs.
> Aside from the obvious worry about head retention, one might worry
> about oxidation products of leftover oil. (As with trub.) On the
> other hand, New Belgium is something like the 11th largest US brewery
> and has trained tasters and all that kind of thing.
>
> Anyway this is kind of interesting.
>
Yeast are voracious fat eaters. They will consume more than they need.
Unless you add truly radical amounts of olive oil - no worries.
The qty cited is way too small to have any impact.
Yeast need O2 for UFAs and sterols. You need both but the sterols are
more critical as growth liming factors.
You'll need to add the lipids in an emulsified form. The yeast need to
wallow in the grease - they can't use the oil in a droplet floating on the
surface. *Maybe adding these at the boil would work.
-S
------------------------------
Date: Thu, 7 Jun 2007 19:46:33 -0400
From: "Al Hazan" <hazan at ptd.net>
Subject: Malt Madness Homebrew Competition
The Lehigh Valley Homebrewers (LVHB) proudly announces their homebrew
competition, Malt Madness will be held on Saturday, September 8th at the
Allentown Brew Works in Allentown, Pa.
All BJCP recognized styles (2004 guidelines) including meads and ciders are
eligible for entry. For complete details and forms, please visit the LVHB
web site at http://www.lehighvalleyhomebrewers.org.
Entries will be accepted from August 15th through August 30th. For drop off
and mail in locations please refer to the LVHB web site. Please, do not
mail entries to the Allentown Brew Works.
BJCP Judges and stewards will be needed. If you are interested please
contact me at the below address. All judges must be BJCP certified (any
ranking) or have relevant experience.
Good luck.
Al Hazan
Competition Organizer
hazan at ptd.net
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End of HOMEBREW Digest #5192, 06/07/07
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