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HOMEBREW Digest #5198
HOMEBREW Digest #5198 Wed 20 June 2007
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Re: Olive oil (Fred L Johnson)
Sweeteners ("A. J. deLange")
Re: Olive oil (**major error rectified**) (stevea)
Re: Olive oil (Fred L Johnson)
Pump Cleaning (Dana Edgell)
Re Darrell's experiment ("Pat Casey")
Re: Corn Mash ("Paul Erbe")
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Date: Tue, 19 Jun 2007 23:13:16 -0400
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: Re: Olive oil
Steve pointed out that the yeast supplemented with oil grew to a
greater extent than did the yeast supplemented with free fatty acids.
The methods weren't described in post, but I must assume that the
authors provided the yeast approximately the same masses of free fatty
acids as they supplied oil, otherwise I don't know how one should
interpret the results.
I don't believe it has been stated how much of each lipid class
(triglycerides, phospholipids, sterol esters, and free fatty acids) was
present in the yeast after the fermentations. I would guess that
triglycerides accounted for the bulk of the difference between the
control fermentation (i.e., the fermentation with no additions) and the
fermentations in which free fatty acids, oil, or lecithin were added.
Regarding the methods used, it is likely that the lipids were extracted
first (Folch-Lees method, chlorofom:methanol, 2:1) and that the lipids
were either fractionated into classes and then each class was
saponified to determine the fatty acid content of each class or the
total the Folch-Lees extraction was saponified.
I'm not surprised that the yeast accumulated significant amounts of
PUFAs when supplied with a source rich in these, especially if the bulk
of the accumulation is as triglyceride. Cells are often more picky with
the type of fatty acid used to esterify to phospholipids, especially
esterification at the 2 position, because the phospholipids serve more
of a structural role and membrane fluidity must be regulated by the
fatty acid composition of the phospholipids and by the amount of
sterols in the membranes, but when it comes to storage triglycerides, I
suspect they esterify whatever happens to be most abundant.
That the yeast utilized the triglycerides (olive oil) still surprises
me. Perhaps they have a triglyceride lipase on the external side of
their cell membrane that can somehow act on an emulsion droplet that
the cell encounters. I'd like to hear more about what is known about
yeast ability to utilize triglycerides from the outside. They are well
known to store triglycerides internally and to be able to use these
stored triglycerides when energy is needed, but I am ignorant of their
ability to utilize external triglycerides. Perhaps there is a yeast
microbiologist among us that can enlighten me.
I know we must be losing folks by now, so I'll refrain from blathering
on.
Fred L Johnson
Apex, North Carolina, USA
------------------------------
Date: Wed, 20 Jun 2007 04:00:45 +0000
From: "A. J. deLange" <ajdel at cox.net>
Subject: Sweeteners
RE:
Anybody know of sweeteners that are definitely not fermentable by Brett,
lactobacillus, and the other creatures in a Flanders Red?
Yes. I'm writing from Victoria where I am at the ASBC Annual Conference.
A paper was given this morning on Palatinose(TM) which is isomerized
sucrose. According to the presenter (Roland Paul of VLB) nothing will
eat this stuff except Schizosaccharomyces Pombe.
A.J.
------------------------------
Date: Wed, 20 Jun 2007 02:13:06 -0400
From: stevea <steve-alexander at adelphia.net>
Subject: Re: Olive oil (**major error rectified**)
Fred L Johnson wrote:
> Steve pointed out that the yeast supplemented with oil grew to a
> greater extent than did the yeast supplemented with free fatty acids.
> The methods weren't described in post, but I must assume that the
> authors provided the yeast approximately the same masses of free fatty
> acids as they supplied oil, otherwise I don't know how one should
> interpret the results.
I apologize, but of course I can't post the full paper here. They
created a lipid extract from malt and then performed a fairly detailed
analysis of the components. The highlight are that the wort addition
consisted of 5.9mg/l of free sterols and 9.5mg/l of total sterols (~20%
campesterol, 5 =% stigmasterol and 75% beta-sitosterol). Also the
addition included 86ppm of free FA and 314 of total FA ( roughly 30%
C16, 14% C18:1 and 55% C18:2, 5% C18:3) . The association of the FAs
was also analysed in some detail. Briefly 3% mono-glyceride ,7%
diglycerie, 18% phospholipid, 28% freeFA, 41% triglyc... and 2%
associates with sterols.
Having analysed the fermentation with this lipid mix addition, they then
performed ferments adding commercial "pure lipids " to similar ferments.
(using beta-sitosterol 10mg/l, lecethin 40mg/l, linoleic 30mg/l,
linolenic 3mg/l, oleic 8mg/l, trilinolenin 7mg/l, trilinolein 80mg/l and
triolein 20mg/l). These were tested as a totoal mix, and as the mix
minus one component at a time. Note that the total-mix has about the
same total sterol but only ~190ppm of FA (vs 314 for the malt extract).
The total mix has very smililar results on fermentation and the
(undetailed report) is that the yeast lipids were affected in a similar
way with the plant sterols addint to the yeast sterols and modestly
shifting the yeast sterol mix, and the FA levels being similar to the
control aside from a big boost in PUFAs.
****
Now here is something I serious mis-reported previously (sincere
apologies). Fred was right. When reading the charts I did not see that
the rows were the total-mix minus one component. So the total mix
provided the best performance (greatest attenuation and highest yeast
mass), and the mix minus the triglycerides was almost as good [bad
mistake here earlier], The mix minus the free FAs was only marginally
better than the control.
****
So Fred was right and I misinterpreted the chart. The freeFAs are the
biggest growth improvement factor and the triglycerides almost
ignorable. [Having said that, note that the amount of PUFAs in the
yeast exceeded the free FA PUFAs added.] The lecethin seems to be a
significant factor, but it is expected that this is because of it's role
as a surfactant.
> I don't believe it has been stated how much of each lipid class
> (triglycerides, phospholipids, sterol esters, and free fatty acids)
> was present in the yeast after the fermentations.
Because of the yeast lipid saponification method no such analysis was
possible. Instead they give breakdowns of the sterol components and FA
components but not the original configuration.
> That the yeast utilized the triglycerides (olive oil) still surprises me.
No surprise - the nearsighted guy misread the crummy xerox copy.
> I know we must be losing folks by now, so I'll refrain from blathering
> on.
Well if they sorted out the imperial vs US measures and metric teaspoons
thread then we have the place to ourselves, so let's continue.
So let's say we have some veggie oil with a desirable FA assay. How
would we go about converting the tri- & di- glycerides to free fatty acids
in a fermentation friendly way ? Conventionally you add a strong base
to the oil (sodium or potassium hydroxide), to create FA salts and free
glycerol. We have no need to remove the glyceol (yeast produce plenty).
Is the amount of sodium or potassium an issue ? It's about 10-16% of
the FA salt mass and if we add 1gm of FA salts to 5gallon of beer it's
about 5 ppm of sodium or 8ppm of potassium. This assumes we
separate any excess x-hydroxide. The low pH of the "soap" shouldn't be
a problem. Not a big issue I think.
Any thoughts on practical aspects Fred ?
-S
------------------------------
Date: Wed, 20 Jun 2007 06:54:06 -0400
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: Re: Olive oil
Thanks, Steve, for looking again at the paper. I was feeling the strong
urge (need) to run to the library to bone up on plant lipid
biochemistry.
Steve wrote:
> So let's say we have some veggie oil with a desirable FA assay. How
> would we go about converting the tri- & di- glycerides to free fatty
> acids
> in a fermentation friendly way ? Conventionally you add a strong base
> to the oil (sodium or potassium hydroxide), to create FA salts and free
> glycerol. We have no need to remove the glyceol (yeast produce
> plenty).
>
> Is the amount of sodium or potassium an issue ? It's about 10-16% of
> the FA salt mass and if we add 1gm of FA salts to 5gallon of beer it's
> about 5 ppm of sodium or 8ppm of potassium. This assumes we
> separate any excess x-hydroxide. The low pH of the "soap" shouldn't be
> a problem. Not a big issue I think.
>
> Any thoughts on practical aspects Fred ?
>
I think Steve's got it right. I think you can simply do the
stoichiometry for the saponification and add an extra 10% base to
ensure complete saponification and then just throw the whole mixture
into the wort. I'm not a real chemist, but I have access to many, and
I'll try to confirm the conditions for the saponification.
Fred L Johnson
Apex, North Carolina, USA
------------------------------
Date: Wed, 20 Jun 2007 08:55:28 -0400
From: Dana Edgell <dedg at lle.rochester.edu>
Subject: Pump Cleaning
HBD,
I have a March pump of unknown origin in my possession. There is a dried
blue substance in the seals & pump area presumably from what it was used
to pump.
What would be a sufficient cleaning protocol to ready this for use in
brewing? Is there a sufficient cleaning protocol to render it safe or
should I not use it?
Thanks for your advice.
Dana Edgell
- --
Dana Edgell
Laboratory for Laser Energetics,
University of Rochester
Rochester, New York
------------------------------
Date: Wed, 20 Jun 2007 23:55:33 +1000
From: "Pat Casey" <pat at bmbrews.com.au>
Subject: Re Darrell's experiment
It's not the grain bill that's making the difference, it's the yeast. Yeast
adsorp iso-alpha acids, as the yeast floc out they remove the iso-alpha
acids with them. This is why the sweet wort is always more bitter than the
finished beer. So with the greater amount of yeast in Darrell's second beer
it ends up less bitter.
A couple of years ago I split a wort. In one half I just sprinkled the dry
yeast, for the other half I rehydrated the yeast and aerated the wort with
an aquarium pump and stone. A very late write up is at
http://www.bmbrews.com.au/?page_id=54
The result was two different beers. The differences were not just due to the
greater adsorption of iso-alpha acids, but also to the far better quality of
fermentation.
Fermentation has a far greater effect than most people realise. With that
little experiment I was expecting noticeable differences, but not to that
extent.
This has all sorts of interesting ramifications, for example with Darrell's
beers I think that the differences in fermentation have dwarfed any
differences between corn and rice in the grain bill. Makes you wonder about
the value of so-called clone recipes.
Pat Casey
Blue Mtns Brewing Supplies/Absolute Homebrew, NSW
www.bmbrews.com.au
------------------------------
Date: Wed, 20 Jun 2007 09:59:05 -0500
From: "Paul Erbe" <paul at theerbes.com>
Subject: Re: Corn Mash
John asks about doing a Corn Mash and letting it sit for up to 8 hours. I
have done long mashes and some overnight mashes. My concern with this style
is that it is normally light and bittered at a lower level. This all means
there is very little to cover any flaws. Letting a mash sit has the
potential for souring. Might be great in a Dry Stout but not so pleasing in
a clean American Lager
Paul Erbe
NW suburbs of Chicago.
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End of HOMEBREW Digest #5198, 06/20/07
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