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HOMEBREW Digest #4853
HOMEBREW Digest #4853 Fri 23 September 2005
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Water Soluble Flux (John Palmer)
Flux ("A.J deLange")
ethyl acetate ester formation and enzymes ("Dave Burley")
E is for email (SteveA)
F is for Flax ("Chad Stevens")
Re: digression on esters ("steve.alexander")
Coconut Cup (Scott Graham)
Rauchbier: smoke grains then grind, or grind first? (Chris Shenton)
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Date: Thu, 22 Sep 2005 22:03:40 -0700
From: John Palmer <jjpalmer at altrionet.com>
Subject: Water Soluble Flux
And it's a high fly ball coming out of left field and nails Palmer in
the back of the head.
Doh!
Haven't thought about soldering in years....
But a quick Google search and I found what I was looking for from
Oatey, the plumbing supplies available at Home Depot.
Here is link to their product page, including usage sheets and MSDS.
http://www.oatey.com/apps/catalog/showskus.asp?
ctg=6&subctg=0&prodgrpid=79
Good Brewing,
John
John Palmer
john at howtobrew.com
www.realbeer.com/jjpalmer
www.howtobrew.com - the free online book of homebrewing
------------------------------
Date: Fri, 23 Sep 2005 12:26:58 +0000
From: "A.J deLange" <ajdel at cox.net>
Subject: Flux
My reasoning is that if the solder and flux in common use by plumbers
for potable water piping runs is suitable for potable water, it is
suitable for brewing water, beer and wort. If this is not the case I'm
in trouble.
------------------------------
Date: Fri, 23 Sep 2005 09:25:36 -0400
From: "Dave Burley" <Dave_Burley at charter.net>
Subject: ethyl acetate ester formation and enzymes
Brewsters:
Steve Alexander says to Chad:
"Not really - and we've just been over this in excrutiating detail."
You said it, I didn't {8^)
"If anyone cares to disprove the statement above, just mix some vinegar (the
C2 fatty acid) with ethanol and wait until you smell the resulting
ethyl-acetate ester (nail polish remover aroma). It will probably take
several centuries since you have forgotten that this is an enzymatically
controlled reaction."
Steve, I see you have forgotten a direct reaction between acetic acid and
ethanol to produce ethyl acetate is possible and does not require an enzyme.
Normal production of ethyl acetate takes place in the presence of an acidic
catalyst or the anhydride of acetic acid (which also removes the by-product
water) can be used. This is how it is made commercially. No enzymatic help
needed.
However, since water is a by-product (which pushes the equilibrium to the
reactant side) and both acetic acid and ethanol are hydrogen bonded, <in
aqueous solution> this direct reaction is slow to non-existent, but if you
take the take the conditions as you laid them out (that is pure acetic acid
and ethanol), I suspect you wouldn't have to wait too long to get some
amount of ethyl acetate.
Keep on Brewin',
Dave Burley
------------------------------
Date: Fri, 23 Sep 2005 09:33:49 -0400
From: SteveA <-s at adelphia.net>
Subject: E is for email
Hmmm - I'm struggling with some new email tools here and hit the
line-wrap wall.
Here's a re-try,
Hi Chad, good to hear from you.
>>Thanks for the clarifications...I'm big into lambic, Flemish Red,
>>and wild fermentations these days so functionally, oats and other
>>lipid sources (I'm still playing with flax seed) do contribute to
>>the ester profile when pedio et. al. are involved, but yes, for the
>>average Joe using Saccharomyces only, you are by and large correct.
FAs from things like grains and flaxseed are typically ~95% C18 and
almost 5% C16 FAs and the rest are chipmunk nuts. About 90% of the
total is unsaturated to various degrees. If you esterify these long chain
FA with ethanol or any fusel from beer, they may smell a bit like pomme
frit, but these cannot directly produce any of the fruity esters we
associate
with beer. Also there is a good volume of evidence that adding these same
long chain FAs to a fermenter decreases final ester level markedly. For
example adding 50ppm of linoleic(an unsaturated C18) to a fermenter
produced an 80% DECREASE in final esters. One of the most referenced
papers ["Ester formation in brewery fermentation", Pedie, JIBv96, pp327-331]
studies the impact of several FAs on yeast AAT in vivo and his data show
that
C18 FAs, oleic, linoleic, linolenic, are very effective, reducing ester
formation about 4-fold.
The long chain FAs from grain and flaxseed almost certainly decrease esters
produced by yeast in normal fermentation.
Now in a non-yeast ferment, say your pediococcus, all bets are off.
These fatty acids could contribute to typical beer esters *if* they
were in the process of being metabolized (beta-oxidation, fat burning
for energy) as this process produces acetylCoA. I would expect that
most bacteria will dive for the sugars first, but when sugars become
less available, I'd speculate that bacteria shift metabolism, perhaps to
beta oxidation.
Another *speculative* possibility is that bacteria may consume these
wort FAs and thus free up a pool of acetylCoA that would have been
used for FA synthesis for their growth. Perhaps bacterial AATs are
not inhibited by these longFAs.
So do FAs+bacteria produce more esters ? I dunno. Do FAs + yeast
fermentation produce more esters ? No - it actually decreases ester
levels dramatically.
>> However, I've seen some papers which suggest increased FA
>>contributions *may* survive through to the end product and *may* be
>>expressed as increased ester profiles.
Well of course some FAs survive, even the virulent head-killing UFAs,
but unless you are adding quantities of an oily grain like whole corn, it's
secondary issue for head. These long-chain FAs clearly have no role in
beer ester formation above the aroma threshold. Show me a study that
measures hmmm say ethyl-oleate above 1ppb in beer and we'll talk.
The only fatty acids that participate at all in beer ester aroma are the
very
short ones - C2, C4, and C6 and marginally C8. These FAs come from
halted long FA synthesis, not normally from long-chain FAs.
>> I have convinced myself through what I've observed in my own
>>brewing, that this is more the rule than the exception. Point was,
>>if I'm making a nice clean ordinary every day APA and want a big
>>head, I wouldn't add oats.
I completely agree that oats don't make for great head, but I doubt the
extra FA content is related. OTOH oats can have a magical impact
on mouthfeel for the right beer.
>> A little wheat, maybe. And if you're really daring, for a five
>> gallon batch, try boiling 2 ounces of whole flax seed in a gallon
>> of water and adding that to the mash; it'll give you a persistent
>> head like merengue. >>
Well the heading improvement from the flax may be due to complex
carbos(most likely) or even foam positive phenolics, but not from
their rather high oil content.
>>And of course, "Typically, to make an ester, all you need is an
>>alcohol and a fatty acid...." was a dramatic over simplification.
>>We were discussing fermentations after all, so the enzymatic
>>processes were a given.
Right, and from previous discussion I know Chadd knows far more on
this topic, but was trying not to veer off course of his main topic.
I think it's worth noting that in normal fermentation that yeast
selection and (mid-late)fermentation temp are the two greatest factors
influencing beer esters and probably the best way to control (up or
down) the final ester level. Adding longFAs is a very effective means
of reducing beer esters, but (beyond starting fermentation with a trubby
wort) cannot be recommended. Other means such as adjusting pitching
level, O2, wort lipid level, dissolved CO2, do work, but have a more
marginal impact.
-S (aka dances_with_ochemists)
------------------------------
Date: Fri, 23 Sep 2005 07:43:13 -0700
From: "Chad Stevens" <zuvaruvi at cox.net>
Subject: F is for Flax
The flax seed for foam stabilization thing....
I'm avoiding the oil by not grinding the grain, rather I'm boiling the whole
flax for the mucilaginous coating which is largely arabinozylose (pentose
sugars) which are used for foam stabilization in firefighting foams. I've
tried this various ways, and it appears boiled and added to the mash at
saccharification is the best regimen. I keep having the problem of too
persistent a foam though, if you can believe that. I get to near the bottom
of my glass of beer and have these little rocks of Gibraltar floating in my
glass. I want a nice smooth persistent head...still working on it.
FWIW,
Chad Stevens
QUAFF
San Diego
------------------------------
Date: Fri, 23 Sep 2005 11:24:03 -0400
From: "steve.alexander" <-s at adelphia.net>
Subject: Re: digression on esters
Dave Burley wrote:
>"If anyone cares to disprove the statement above, just mix some vinegar (the
>C2 fatty acid) with ethanol and wait until you smell the resulting
>ethyl-acetate ester (nail polish remover aroma). It will probably take
>several centuries since you have forgotten that this is an enzymatically
>controlled reaction."
>
>
>Steve, I see you have forgotten a direct reaction between acetic acid and
>ethanol to produce ethyl acetate is possible and does not require an enzyme.
>
>
Thanks Dave, but I did not forget this fact, when I explicitly stated
the formation is
rate limited by the enyzme catalysis. You are correct to point out
that the Fischer
esterification reaction is real, as a careless reader might assume I
meant it was
non-existent rather than merely ignorable. When I wrote "... take several
centuries" , I was implying that the reaction is real, but *exceedingly*
slow.
A more accurate and detailed statement is that directly production of
esters from
alcohols and carboxcylic acids is possible, but of absolutely no
significance
in brewing.
The reaction Dave mentions, the Fischer esterification reaction:
alcohol + carboxcylic_acid <=> water + ester
does spontaneously occur, along with it's inverse, but the rate is so
slow that it
is completely meaningless for the production of flavor threshold levels of
esters in beer. In industrial ester production a strong acid, typically
HCl, and
rather difficult to manufacture and unstable anhydrous acetic must be used
to drive the Fischer reaction rate - not brewing conditions or even close.
As another demonstration that this reaction is meaningless in practical
brewing, note that finished beer has some 150-200ppm of acetic and about
50000ppm of ethanol, and is near the lowest pH (almost) of it's journey
from wort
to a cup. So a beer sitting in storage is in it's optimal state to
drive the Fischer
reaction forward and create new esters. Does anyone seriously contend that
beers become more estery during months or years of storage ? Of course not.
> this direct reaction is slow to non-existent
>
Is there an echo in here ?
>[...] but if you
>take the take the conditions as you laid them out (that is pure acetic acid
>and ethanol) [...]
>
>
"Vinegar"(see my quote) is not the same as pure anhydrous acetic (or
even close), nor did
I state or imply pure ethanol. This forum is about brewing and brewing
conditions are
implicit in all discussions here. If we could get threshold levels
of esters from
say ~10% or even 20% solutions of ethanol and acetic it might imply
something about
beer esters. We agree you can't and that's sufficient for HBD.
-S
------------------------------
Date: Fri, 23 Sep 2005 15:14:12 -0400 (EDT)
From: Scott Graham <grahams at cs.fiu.edu>
Subject: Coconut Cup
Greetings from the members of the Miami Area Society of Homebrewers (MASH)
in Miami, FL.
It is almost time for this year's (and 8th annual) Coconut Cup homebrew
competition. We are accepting all of the 2004 BJCP categories, as well as
our special COCONUT BREW category.
Entries of TWO bottles are due by October 26th. Please use the on-line
entry form available at the Coconut Cup website,
http://hbd.org/mash/coconut.html .
This year's Coconut Cup is being sponsored by Briess, Left Hand/Tabernash,
Puterbaugh Farms/Hops Direct, Brew Your Own, Hopunion, Cargill, William's
Brewing, and the Titanic Brewing Company; other sponsors are pending.
There will be more prizes and raffles than in past years, so please enter
early and enter often.
Final judging and the awards ceremony will be held on November 5th, 2005
at the Titanic Brewing Company in Coral Gables, FL. Please contact me if
you are interested and willing to judge. We will have some fun activities
planned for the out-of-town judges.
I hope to see you (or at least your beers/meads/ciders) in Miami!
Scott Graham
Coconut Cup Judge Coordinator
MASH Librarian
------------------------------
Date: Fri, 23 Sep 2005 15:53:17 -0400
From: Chris Shenton <chris at Shenton.org>
Subject: Rauchbier: smoke grains then grind, or grind first?
I'm planning on doing an all-grain Rauchbier this weekend, and smoke
the grains myself. I gather 10-20% or the grain should be smoked.
>From my searches, most folks seem to soak or wet the grains then smoke
them in a barbecue or smoker for 30-45 minutes on a screen.
This may sound stupid, but would you grind the grain in the mill
before soaking and smoking, or smoke first then grind? If the latter,
do you need to dry out the grain completely before grinding? I've got
a Corona mill if that makes a difference.
Thanks.
------------------------------
End of HOMEBREW Digest #4853, 09/23/05
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