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HOMEBREW Digest #2080
This file received at Hops.Stanford.EDU 1996/06/24 PDT
Homebrew Digest Monday, 24 June 1996 Number 2080
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Shawn Steele, Digest Janitor
Thanks to Rob Gardner for making the digest happen!
Contents:
Re: Making a brew kettle from a keg (keithzim@tgn.net)
Newbie Question: Priming (Bill Rust)
Moonshine Recipe and Other Thoughts (aesoph@ncemt1.ctc.com (Aesoph, Michael))
Priming levels revision ("Dave Draper")
RE: "Ginjo" beer ("Richard Okambawa")
spoiled starters-update (Peter Thompson)
ester mystery solved! (Andy Walsh)
meat grinders ("Jared B Froedtert")
Re: esters ("Tracy Aquilla")
Re: new questions ("Dave Higdon")
Old Dominion Stout (TArnott@aol.com)
Andechs Monastic Brewery in Chicago? (paa3983@dpsc.dla.mil (Mike Spinelli))
Counter-Flow Chiller/Time it takes to chill (George_De_Piro@berlex.com (George De Piro))
long ester post (awalsh@world.net (Andy Walsh))
1997 Sam Adam's Contest (dharsh@alpha.che.uc.edu (David C. Harsh))
[none] (John Adams)
potato and rice ("Dave Higdon")
Pet 'peaves'/oxidation/acetaldehyde/bitterness of bitters (STROUDS@cliffy.polaroid.com)
Lodo Brewer's Festival Trip Report (John Adams)
Tap Water (Michael Mahler/Shiva Corporation)
Bitter? (Kerry Drake)
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----------------------------------------------------------------------
From: keithzim@tgn.net
Date: Sun, 23 Jun 1996 15:28:21 -0500
Subject: Re: Making a brew kettle from a keg
I agree that most kegs are probably S.S. I had a boilermaker
friend of mine convert my keg into a brew kettle. First he cut off the
top and smoothed the edge. He weleded another piece of S.S. into the
hole in the middle of the keg. In remaining hole at the bottom of the keg
he welded in a S.S. fitting that had threads on the inside so that I could
either seal up the fitting or install a valve. He also welded four swiveling
handles (which he made) on the outside (two near the top and two about 2/3 way
down). He did this not knowing if I wanted to pour the wort. If this is what
you had planned it would make it quite easy for two people. The keg fits on top
of a cajun cooker burner pretty good. Also if your keg is like mine with the
odd shaped bottom you will have to be careful when cooking to ensure that
the extract does not burn on the bottom.
I would venture a guess if you found someone who can weld on S.S. that
person could probably help you convert your keg to what you want.
Keith Zimmerman
keithzim@tng.net
------------------------------
From: Bill Rust <wrust@csc.com>
Date: Mon, 24 Jun 96 12:01 EDT
Subject: Newbie Question: Priming
Dave writes:
Welcome to the Wide World of Worts! Let me start by saying "Relax, Don't
Worry". Sounds like you're off to a whale of a start!
>My first attempt is a Porter, I used the recipe from "Brewing the World's
>Great Beers" to the letter,
excellent book, great recipes!
> except that I used two stage fermentation. I
>bottled after about 13 days fermentation. My OG was 1.042 and the FG was
>1.011.
Sounds perfect to me...
> I primed with 1/2 cup sugar. Being anxious I tried my first
>bottle last night (8 days after bottling). My problem is this - The
>flavor is pretty good but I have no head to speak of. I realize that
>this is really too soon and that it should condition for at least
>another 3 weeks but I really expected more. What head there is, is thin
>and dissipate almost immediately. What could cause this or what can I
>add or am I just too impatient (patience is not one of my virtues).
Well, maybe it should be. 1/2 cup of sugar is a little on the light side
(appropriate for English milds and cask conditioned ales...), but it should
be fine. You need about 2 weeks to carbonate fully and another to clear the
yeast from suspension for most ales. Also, what type of sugar did you use?
People use anything from cane, corn, brown, malt extract, to molasses. Most
kits recommend corn sugar, but I've had excellent results using light brown
sugar. I've also kraeusened with excellent results.
How did you prime? Did you make a syrup in a pint of water like Dave Miller
recommends, and add at bottling time? Some folks add a little to each
bottle, or add it dry to the carboy (NOT recommended). These thechniques
can lead to inconsistent results. The syrup technique is very reliable, IMO.
>One other question. My second batch (brewed the day I went to the second
>fermentation on the first batch) is a stout. My OG was 1.080, the
>gravity reading last night was 1.022 so I figure that it is just about
>ready to bottle. Problem is this, I tasted the sample and while I
>realize that the alcohol content is high in a stout that is almost all I
>could taste. Again am I just quick to judge, will this mellow out so
>that I can taste the beer.
Again, you *are* quick to judge. I'm pretty sure what you are tasting are
phenols, a burning sensation in the back of your throat (like brandy). That
tends to occur in high gravity brews like yours, at first. Just wait about
a month or two, and I think you'll be pleased with the results. I just
entered a dopplebock in the NHC. At first racking it tasted like cognac!!
Only one month later it settled down to a mellow, malty flavour. SG. 120!!
>I know that I haven't given enough information to get any really
>definitive answers but would appreciate any general guidelines from the
>world of wisdom out there.
>
>Email would probably be best since from what I've read in HBD is far
>ahead of my brewing experience and would probably bore everyone else to
>tears.
Actually, if no one ever responded to the *newbie* questions, how would any
of us gain any wisdom? Sounds like you're doing great. Believe me, it gets
easier to be patient when you have a few homebrews in stock to tide you over.
Skol.
-------------------------------------------------------
Bill Rust, Master Brewer |
Jack Pine Savage Brewery | Im Himmel gibt's kein Bier,
Shiloh, IL (NACE) | Drum trinken wir es hier!
-------------------------------------------------------
- ------------------------------
------------------------------
From: aesoph@ncemt1.ctc.com (Aesoph, Michael)
Date: 23 Jun 96 20:54:27 EDT
Subject: Moonshine Recipe and Other Thoughts
Dear All:
I also posted a "stupid" question regarding distilling beverages a while
back. A friend of mine swore adamantly that distilling was _NOT_
illegal. However, replies to my posted question said otherwise,
specifically:
A) It's illegal
B) It's dangerous
C) Don't do it
This begs the question, "What is legal?" I make wine that routinely
hits >20% alcohol. Is there a limit on % alcohol, or is it some other
criteria? Can one use the "ice brewing process" to increase alcohol
content? - or is that illegal too? In any case, one can enjoy life
without distilling ANYTHING!!!!!!!! See you around...
==================================================
Michael D. Aesoph Associate Engineer
==================================================
------------------------------
From: "Dave Draper" <david.draper@mq.edu.au>
Date: Mon, 24 Jun 1996 07:07:07 +10
Subject: Priming levels revision
Dear Friends,
As some of you may recall, I posted some time back on a preferred
method for determining priming levels in bottled beers, using
information compiled by Mark Hibberd and some of my own calculations.
Recently I discovered an error, or rather Mark did, in calculating
the amounts when using sucrose to prime. My web page has now been
corrected, so I am asking anyone who has interest to go there and get
the correct value for priming with sucrose. My beer page URL is
http://audio.apana.org.au/ddraper/beer.html
Cheers, Dave in Sydney
"Just what we need, another wanker with an attitude!" ---Rob Moline
- ---
***************************************************************************
David S. Draper, Earth Sciences, Macquarie University, Sydney NSW Australia
Email: david.draper@mq.edu.au WWW: http://audio.apana.org.au/ddraper/home.html
...I'm not from here, I just live here...
------------------------------
From: "Richard Okambawa" <okambawa@UQTR.UQuebec.ca>
Date: Sun, 23 Jun 1996 18:44:59 +0000
Subject: RE: "Ginjo" beer
Harold R. Wood" <hrwood@uog9.uog.edu> wrote
Subject: "ginjo" beer
>Does anyone out there know anything about "ginjo" beer. This is
>apparently a barley malt based beer fermented with sake yeast. Has
>anyone made this or tasted it? Is there a commercial example? I know
>nothing of sake, what characteristics would a sake yeast impart?
I don't know ginjo beer but I know a bit about sake and hope this can
help. If your description is correct, ginjo beer can easily be brewed
at home.Wyeast and Yeast Lab have a liquid culture of sake yeast. It is a
Saccaromyces (S. sake? ref. the book of Fred Eckardt, Sake USA), a
high alcohol tolerant strain. I'm not sure that the yeast can grow in a high
gravity wort. You need to know the alcohol content of ginjo, the
presence of the moldy flavor of sake to have a good design. I don't
know exactly the flavor thak sake yeast impart because sake flavor is
the result of two effects: mold activity from the koji and yeast and
mold activity in the moto ( mixture of steamed rice and koji and
yeast, as the mold which produced amylase during the manufacture of
the koji is still alive). If koji is used and the product is not
sterilised and the enzymes deactivated, the product will be
biologically unstable.
David R. Burley answered:
>amylase producing mold called Aspergillus Niger and yeasts. Amylase
>acting on the starch produces sugar from unmalted grains. Rice beer
>has been produced for centuries using this method.
My comments:
- - Koji is not a mixture of mold and yeast. "Jiu niang"used in the
production of chinese jiu is a mixture of molds and yeast (bacteria
also).
- - Technically, a kind of koji can be made by growing Aspergillus niger
on polished and steamed rice. Industrial food grade glucoamylase
is manufactured using Asp. niger. But all the litteratures I have read
about sake refer to Asp. oryzae, not Asp. niger.
Cheers.
Richard Okambawa
"Le vin ne soule pas. C'est le buveur qui se soule" Chinese proverb.
Sorry, I don't have the translation in english.
------------------------------
From: Peter Thompson <pthompso@coe.edu>
Date: Sun, 23 Jun 1996 17:17:17 -0500
Subject: spoiled starters-update
Thanks for the many private responses I've gotten. The gist of them is
that (though people are _very_ sympathetic) this has never happened to
anyone else. Some very thorough explanations of sanitizing processes
(for which I'm grateful) confirm my thinking that I am being quite
fastidious in my process. Several people wondered if my starters
really had gone bad. A point that had not occurred to me. They have,
however, been mighty stinky and taste bad as well. Unpleasant cidery
aroma, skunky taste. Other noses and palates have confirmed that
this seems to be infection.
I bring this issue back to the table because I am trying an
experiment and I wonder if it's valid. I have reproduced the entire
process, minus the yeast. Doesn't it figure that if I have bacterial
infections within 12 hours of starting the yeast, that those same
microbes will jump at some nice sweet malt? So far (48 hours) it
still smells like sweet wort. No sign of infection. Does this suggest
that I have some BAD YEAST? Or am I barking up the wrong tree?
Three of the four spoiled starters have been Wyeast's London ESB, the
other was their Swedish Porter. Has anyone else had success with these
strains?
thanks,
Peter Thompson
------------------------------
From: Andy Walsh <awalsh@crl.com.au>
Date: Mon, 24 Jun 1996 13:36:37 +1100
Subject: ester mystery solved!
Tracy writes:
>It's extremely fruity (apple and orange hints), noticeably alcoholic, and
>bitter, but I don't detect much diacetyl or ethyl acetate. Since I
>dry-hopped with about 4 oz. of EKGs (in 5 gallons), there is also a massive
>hop presence which may be masking the other flavors and aromas.
and Al Replies:
>Whoa!!! 4 ounces of EKG and you can still smell esters? That's some
>sniffer you've got there... actually, I don't think that any human can
>identify esters with that kind of hop aroma. Did you judge the fruity
>aromas before you added the dryhops? Otherwise, I can't believe that
>you really smell any esters at all there. Sorry...
This got me thinking. What is hop aroma? I checked Hough (V2 pp450-453)
and discovered that about 30% of the smell of hops is due to esters!
Hops are generally not regarded as contibuting to beer esters in the texts,
but that is because commercial operations usually do not dry hop! (it is
costly to remove the hops, and the flavour changes rapidly with time, both
general commercial no-no's) I decided to do some calculations on the ester
levels in Tracy's beer as contributed solely by the massive amount of
dry hops he used (all data from Hough).
Hop oil is about 1% of total hop weight. Esters contribute approximately
15% by weight of that, but provide about 30% of the hop aroma (Hough says
"oxygenated hydrocarbons" but in the table he provides they are just
about all esters). The other major constituents are the hydrocarbons
(myrcene, humulene etc.), providing the bulk of the aroma. (Hough does
not give data on EKG esters, so I used his Fuggle numbers as an
approximation)
The two esters most dominant in terms of aroma are methyl thiohexanoate and
methyl dec-4-enoate. The former would be present in Tracy's beer at more
than 1000 times aroma threshold (350 ppb) and the latter about 100 times
threshold (1000ppb). This assumes a 100% "aroma utilisation" which is
obviously incorrect (it would be impossible to actually know what it would
be as it would depend upon too many factors), but it does give us some
idea of the magnitude of beer esters as contributed by dry hopping. There
are many others that are also way above threshold, but you get the idea.
Hough also says that the taste thresholds are generally about 10 times less
than the aroma thresholds, so presumably ester flavour is also contributed
to by dry hopping.
This post may come either before or after my other long post (all my
posts bounce now that Shawn has put that sender checker thing in - either
that or he has banned me!), but I think this should be read in
conjunction with the other. ie. to FACTORS THAT CONTRIBUTE BEER ESTERS,
add dry hopping.
This seems to be the most likely explanation of Tracy's beer esters as
it does not defy conventional wisdom.
Unlike the acetates that are the main esters produced by fermentation
(which are mainly either solvent or banana and undesirable), the hop esters
are all quite complex, and would contribute fruitiness. It appears
to me that a good practice on ester control would be to minimise
the acetates in the fermentation (see my other post), and add dry hops
for the desired effect. The "hoppiness" of dry hops disappears after about
6 weeks (from personal experience), so may be good for Belgians etc. that
should be estery but not solventy or bananary. They should not be hoppy
either (generally) but if you wait a couple of months (as you should with
Belgians anyway) that will disappear. Obviously different hops have different
ester profiles, so experimentation is required for a desired effect. The
aroma hops are obviously good starting points as they contain the most
hop oils. You could also try packaged hop oils, but they must be prepared
by vacuum at 25C rather than a boil as the latter would have far fewer
esters.
This may also explain why lagers are generally kettle hopped rather than
dry hopped. Kettle finish-hopping would boil off most of these volatile
esters, which are undesirable in lager style beers. It also might explain
the estery fruitiness of English ales, since dry-hopping is common practice
commercially with this style.
- --
Andrew Walsh CHAD Research Laboratories
Phone (61 2) 212 6333 5/57 Foveaux Street
Fax (61 2) 212 1336 Surry Hills. NSW. 2010
email awalsh@crl.com.au Australia.
------------------------------
From: "Jared B Froedtert" <froedter@pilot.msu.edu>
Date: Mon, 24 Jun 1996 08:42:09 -0400 (EDT)
Subject: meat grinders
Hello to y'all in brewingland,
I've have recently made the switch to all-grain batchs and love the
challenge so. I have fabricated all the necessary equipment to the best of my
ability (mash-tun, sparge arm, etc...). I now need to purchase a grain mill.
The brew shop i buy my grain from always will let me use his in store mill, but
i'd like to have one of my own. I"ve seen them for sale for $40 - $80,
depending on the style. But i've been to some antique stores with my
significant other lately and notice the old style meat grinders for sale for
under 10 bucks. Most of them are still in perfect condition, and come with a
variety of wheels that can be used to adjust the particle size. I was
wondering if one of these can be used as a grain mill? If not i guess i'll buy
a corona or a phil. If anybody out there has done this or attempted this
please let me know; or just gimme your opinion on why it would or wouldn't
work,k, i need feedback.
Th
man yeast makes me fart,
jared freodtert
------------------------------
From: "Tracy Aquilla" <aquilla@salus.med.uvm.edu>
Date: Mon, 24 Jun 96 10:50:05 CDT
Subject: Re: esters
In Digest #2078:
korz@pubs.ih.att.com Al K. wrote:
>Tracy writes:
>>It's extremely fruity (apple and orange hints), noticeably alcoholic, and
>>bitter, but I don't detect much diacetyl or ethyl acetate. Since I
>>dry-hopped with about 4 oz. of EKGs (in 5 gallons), there is also a massive
>>hop presence which may be masking the other flavors and aromas.
>
>Whoa!!! 4 ounces of EKG and you can still smell esters? That's some
>sniffer you've got there...actually, I don't think that any human can
>identify esters with that kind of hop aroma. Did you judge the fruity
>aromas before you added the dryhops? Otherwise, I can't believe that
>you really smell any esters at all there. Sorry...
Hey buddy, watch what you say about my sniffer! Of course I tasted the beer
before dry-hopping, don't you? Actually, this batch was dry-hopped twice (2
oz. each time), since the first two ounces just didn't quite do the trick.
The apple aroma (ethyl-hexanoate?) is so intense it even comes through the
super hop nose, but I doubt you can smell it all the way from over there!
Tracy
------------------------------
From: "Dave Higdon" <DAVEH@qesrv1.bwi.wec.com>
Date: Mon, 24 Jun 1996 09:18:17 EST
Subject: Re: new questions
When bottling you should use 3/4 - 1 cup of priming suger. And don't
worry about your stout until after about 2 months of aging in the bottle
there should be some flavor then. My second batch was a porter that
had no taste at all at first and I worried also. After letting it age 2 months
or so the coffie I steeped after boiling brought out a wonderful
chochlate flavor and sweetness.
Try your beer after another week if there is no carbonation then your
going to have to open up each bottle and add more.
------------------------------
From: TArnott@aol.com
Date: Mon, 24 Jun 1996 06:41:47 -0400
Subject: Old Dominion Stout
Hi All!
I've got two quick questions (sorry to waste the bandwidth). The father (a
good guy in his own right) of a friend of mine is very taken with Old
Dominion Stout and I thought I would attempt to make some for a party he's
having. Does any one have a recipe? Extract or all grain, either would be
fine!
The second question is this (oh, no. Its not homebrew related and he's gonna
ask anyway!) Does anyone know where, if anyplace, Old Dominion can be
purchaced in Massachusetts (Boston area)? Mr. O raved about it and I must
admit I would like to try it first hand.
Private E-Mails are fine, I'll post the recipes, etc.
TIA
ted
------------------------------
From: paa3983@dpsc.dla.mil (Mike Spinelli)
Date: Mon, 24 Jun 96 09:01:45 edt
Subject: Andechs Monastic Brewery in Chicago?
HBDers,
When in Bavaria a couple weeks ago, my in-laws' next door neighbor told me that
the Andechs Monastic brewery located south of Munich was helping out a
financially troubled Monastery somwhere in the Chicago area. The money came
with one condition. The brothers in Chicago had to adopt the art of brewing.
Has anyone heard about this? I do know that Andechs although no longer run by
Monks, makes the best doppelbock I've ever tasted. Unfortunately it's not
imported into the U.S.
Mike in Cherry Hill NJ
------------------------------
From: George_De_Piro@berlex.com (George De Piro)
Date: Mon, 24 Jun 1996 09:18:47 -0700
Subject: Counter-Flow Chiller/Time it takes to chill
This posting is irrelevant to all but one whose name and address I
don't recall. Sorry to bore the rest of you!
A few weeks ago somebody (from a Southern state, I believe. Alabama,
maybe?) asked how I could get my wort through my chiller so much
faster than he could. After several somewhat bizarre explanations, I
can finally give you the real answer. My chiller is 3/8" tubing, NOT
1/4", which is what I believe you use, and what my sieve of a memory
told me I use! I measured it the other day, and now know better.
Sorry if I caused you distress!
George De Piro (Nyack, NY)
------------------------------
From: awalsh@world.net (Andy Walsh)
Date: Sun, 23 Jun 1996 15:42:30 +1000 (EST)
Subject: long ester post
(this is a little bit delayed as it has bounced 3 times so far!!!
AAARRRRGGGGHHH!!!)
Subject: BOUNCE homebrew: looks like an administrative message
Date: Sun, 23 Jun 96 5:09:51 GMT
Sender: Homebrew@aob.org
Source-Info: From (or Sender) name not authenticated.
***********
David R. Burley
writes
>Brewsters,
I always thought a brewster was a female brewer.
Mate, are you insinuating something?
>Finally, on the question of ester formation. There seems to be two
diametrically
>opposed opinions, sometimes put forth by the same person. More oxygen will
give
>more, or sometimes, less esters? I'm confused.
As should everyone else be. There *are* two opposite opinions.
>Since these products are require oxygen, how could increasing the
>oxygenation reduce the formation of ester and related intemediates? What am I
>missing?
I was going to leave this until I had some more data, but I might as well
post what I have learned so far. Firstly, let me say that I have limited
first-hand practical experience in this subject (but it is on the way), but
I have done a little reading recently. There has been a great deal of
research into ester formation in the brewing journals, which are all in
general agreement with one another. I shall blatantly plagiarise from the
one I consider to be the best summary(1). I suggest that anyone interested
should get hold of the original article(s).
********** CONVENTIONAL WISDOM FOLLOWS *************
Firstly, esters are formed within the yeast cell via:
(R1)OH + (R2)COOH -> (R2)COO(R1) + H2O
(ie. alcohol + organic acid -> ester + water)
Their concentration in beer is much too great (about 1000 times) to be made
(uncatalysed) in this manner when one considers the duration of fermentation
and the rate of reaction. It has been suggested that they may be formed in
S. Cerevisiae (ale yeast) by a biochemical pathway involving alcohols, fatty
acids and co-enzyme A (CoASH).
The fatty acids are activated by combining with CoASH to form acyl CoASH.
The most common of these is acetyl CoA. These activated acids then react
with alcohols to form esters, catalysed by ester synthesising enzymes (there
may be more than one, depending on the activated acid concerned) but as most
work has been concentrated on acetate esters (they are the most abundant),
the most studied of these enzymes is alcohol acetyl transferase (AAT). If a
wort contains several individual activated acids and alcohols, competitive
inhibition could take place. ie. some esters could be formed in preference
to others. In addition to ester synthesising enzymes, there also exist ester
hydrolysing enzymes (esterases), which may break down esters to alcohols and
acids. The hydrolysis of acetate esters by esterase is much slower than for
other esters such as ethyl octanoate. This could help explain why acetate
esters are so abundant in beer in proportion to other types.
(the following paragraph is conjecture)
As you can see, it is complicated! The important points from the above are
that alcohols, acids, CoASH and activation enzymes are required for ester
synthesis. Esters formed may inhibit synthesis of other types, as can the
concs of different alcohols. I think most would agree that ethyl acetate
(solvent, nail polish remover) can be very undesirable in high concs.
Iso-amyl acetate (banana) is also not very nice in high levels other than
weizen. (I should point out that either near threshold will provide fruity
overtones without dominating, and can be OK in some styles) Some of the
higher esters (formed from fusel alcohols) have fruity traits which *are*
desirable in many ale styles. If we could arrive at a wort composition that
inhibited synthesis of the first two by aiding synthesis of the higher
esters, we might be on the right track (for ales anyway).
(back to conventional wisdom)
As acetyl CoA is clearly related to the level of acetate esters, any factors
which increase the intracellular pool of acetyl CoA will elevate ester
production provided that a pool of (fusel) alcohols exist. Acetyl CoA plays
a key role in cell growth (amino acid/lipid/fatty acid biosynthesis/ TCA
cycle), hence any restriction of cell growth will elevate acetate esters, by
increasing the availability of acetyl CoA for ester synthesis. ie. a
deficiency of oxygen will lead to slower cell growth (O2 is required for
sterol/fatty acid biosynthesis) and hence greater availability of acetyl CoA
for ester biosynthesis.
This is not just theory, and is confirmed by results from many different
experiments, all of which show greater ester levels with decreased wort
oxygenation. For example(3):
8ppm oxygenated wort 4ppm low O2 wort
total esters (mg/l) 24.2 34.6
lipid compounds
C16:0 2010 1540
C16:1 1480 1080
C18:0 1500 1360
C18:1 1010 580
C18:2 880 510
ergosterol 1250 350
conditions:0.1% trub solids by wet volume, OG=1.048, 75% malt, 25% glucose,
S. Cerevisiae, pitching rate =1.5e7 cell/ml, 12-18C fermentation temp.
Notice the trends in sterol levels (in particular) and esters. These figures
just refer to original DO levels. Controlled oxygenation during fermentation
can lead to even more striking results(2).
It has been shown(2) to be particularly important in high gravity brewing.
ie. the higher the gravity, the lower the O2 levels, the greater the esters.
Therefore, as high gravity brewing is used extensively in commercial
operations (to be diluted post-fermentation), controlled aeration is also
used as a matter of course to bring ester levels down to an acceptable
value. This is one reason there has been so much professional research on
this topic (ie. it means money!).
******** FACTORS WHICH AFFECT BEER ESTER LEVELS(1) **********
Comment - the theories below have arisen via controlled experimentation from
multiple sites. Even if the theory is not perfect, the results still show
strong trends.
YEAST STRAIN: Each yeast produces its own ester profile, and some strains
produce considerably more than others.
WORT COMPOSITION: In an all-malt brew, where there is abundant FAN, the
yeast generally thrives until the O2 supply is diminished. However, as FAN
is still available, metabolites, including acetyl CoA, are still formed,
stimulating ester synthesis. ie. Adjunct brews (low FAN, hence lower acetyl
CoA levels) will tend to have lower esters than all malt brews under similar
conditions.
The lipid content of wort can also affect ester levels. In particular, the
unsaturated fatty acids, linoleic (C18:2) and linolenic (C18:3) acids cannot
be synthesized by yeast and are derived largely from trub(3). They aid
fermentation and decrease ester levels. ie. trub rich worts are associated
with lower ester levels and better fermentation (fatty acids are associated
with poor beer stability however).
WORT AERATION: results in increased yeast growth since O2 is essential in
the biosynthesis of sterols and unsaturated fatty acids. Increased yeast
growth results in additional demand for acetyl CoA for that purpose,
resulting again in lower ester synthesis. Even a low rate of aeration during
fermentation can strongly inhibit ester formation(1,2,3,4,5,6).
OPEN FERMENTATION:As David Burley comments, open fermentations aid DO
levels. They have been shown to also decrease ester levels (see aeration) (4).
PRESSURE: There are conflicting reports, but pressurised fermentation
appears to decrease acetate ester levels. This conflicts with the theory,
since yeast growth is also retarded (shows the theory is not perfect).
PITCHING RATE: When pitching rate is increased by a factor of 4, ester
synthesis is reduced.
SUSPENDED SOLIDS (eg. trub, diamataceous earth, bentonite, activated
carbon). Tends to reduce dissolved CO2 levels by acting as nucleation sites.
High CO2 is toxic to yeast, hence solids lead to better fermentation, lower
esters.
TEMPERATURE: increases esters.
- - can make membrane more fluid increasing AAT activity and increasing ester
diffusivity
- - temperature alone may increase AAT activity.
********** WHEN ESTER SYNTHESIS OCCURS ***************
Originally it is slow due to yeast growth. After about 8 hours there is the
first peak as yeast growth slows down. When fatty acid/sterol synthesis
finally stop there is another peak at about 20-30 hours and is short-lived.
(there is debate over whether this peak is due to increased acetyl CoA
availability or increased AAT activity at this time). Thus control of esters
is best performed within the first day or two of pitching.
(back to conjecture)
********* WHAT DOES IT ALL MEAN ****************
Tracy has practical experience indicating what appears to be the opposite of
what I have summarised above (ie. Tracy says yeast growth leads to greater
ester production). The general scientific brewing texts do not support this
(please somebody tell me if they find anything to the contrary!). He quotes
Greg Noonan (whom we all know and respect) and also Dr. David Brown of
Scottish and Newcastle in support.
I think that basically science attempts to explain things we observe in
nature. If science does not explain our observations, we are possibly
measuring the wrong thing. It appears to me that most all of the research
has been directed at smaller acetate esters (the most predominant), and ale
yeasts, and is most likely correct in its measurements and theories
concerning these. However, that same research says that ester biosynthesis
can inhibit the formation of others: hence it is possible that some esters
other than acetates are formed largely under conditions detrimental to
acetate production! Science also says that yeast growth leads to greater
fusel alcohol levels. Higher fusel levels may also form different ester
profiles! (the most common ester, ethyl acetate, is formed from ordinary old
ethanol and acetic acid). Hence aerated fermentations could still lead to an
overall big reduction in ester levels (ie. much lower ethyl acetate and
iso-amyl acetate levels) but higher levels of other esters that then become
more obvious in the flavour profile(6). This could help explain the
empirical evidence as reported by Tracy.
So, in short, the jury is still out as far as I am concerned. I shall
continue to research this topic and report here if I find anything
interesting. In the meantime, we're homebrewers, not science labs, so go try
a few things and taste the results! This is why I'm interested in hearing
results from individuals.
I'm sorry about such a long post,
Andy.
References:
(1) H. Peddie. Ester formation in brewery fermentations. JIB. v96 pp327-331.
1990.
(2) R. Anderson et al. Quantitative aspects of the control by oxygenation of
acetate ester concentration in beer obtained from high-gravity wort. JIB.
v81. pp296-301. 1975.
(3) A. Lentini et al. The influence of trub on fermentation and flavour
development. Proc 23rd Conv. Aust. IOB. pp89-94. 1993.
(4) A. Palmer et al. Ester control in high gravity brewing. JIB. v80.
pp447-454. 1974.
(5) D. Quain. Studies on yeast physiology-impact on fermentation performance
and product quality. JIB. v95. pp315-323. 1988.
(6) Hough et al. Malting and Brewing Science vol II 2n edition. table
22.8.D. Esters p793. also pp607-608.
*************************************************************
Wohlgemuth Walsh from Sydney
email: awalsh@world.net (or awalsh@crl.com.au if you prefer)
I *am* from here. Wanna make sumthin of it?
*************************************************************
------------------------------
From: dharsh@alpha.che.uc.edu (David C. Harsh)
Date: Mon, 24 Jun 1996 09:40:42 -0400
Subject: 1997 Sam Adam's Contest
Greg Hawley asked in #2079 about the Boston Beer's 1997 World Homebrew
Contest.
> ...they are charging a $5 entry fee.
> ...they are requiring 4 bottles instead of three
> ...they want you to reserve 3 more bottles if you advance
> ...what happened to the 1996 World Contest.
This is purely secondhand, but I have heard that the BBC is attempting
to
fix some of the problems that occured last year with the judging. This
year the judging will be coordinated with the BJCP, and lodging will be
provided for judges that want to make the trip to Boston to help judge.
Granted, it does seem like BBC is using homebrewers to help with their
own
market research and recipe development, but entry is optional. I'm not
going to defend Jim Koch's marketing practices, but at least jk doesn't
post on the digest and claim every beer made is vastly inferior to his.
Just don't kid yourself: This is no "best beer" contest, it is a "most
marketable" contest. Koch isn't that stupid if he can get homebrewers
across the country to provide free product development expertise and at
the
same time get people to see it as supporting homebrewers.
Cynical? Me?
Dave
------------------------------
From: John Adams <jadams@pipeline.cnd.hp.com>
Date: Mon, 24 Jun 1996 09:16:20 -0600
Subject: [none]
3rd Annual Lodo Brewers Festival
The Lodo Brewers Festival was held Saturday and Sunday, June 22/23 in the
shadow of Coors Field in Lower Downtown Denver. This years event was a
bit different from the past. Some of the changes were good and some areas
need a little work.
They have expanded the event to include 3 Colorado wineries (no thanks), a
meadery (yea!), and a soda 'poppery'. The Single Malt Scotch Society was on
hand providing information (but no drinks) and a local cigar shop was
selling stogies (would have gone great with a scotch).
Unfortunately the event itself needs a promotional boost. The plastic
mugs have not changed in 3 years as were the t-shirts on sale. There was
no real program guide. There was an incomplete pull-out section from last
week's Denver Post. This event hit the road running as a clone of the Fort
Collin's sponsored Colorado Brewers Fest (being held next weekend) but hasn't
changed much since.
All and all it was a pleasant day with some good brews. My personal
'Best Of Show' being awarded to Palmer Lake's Locomotive Stout. Palmer
House is a new brewery with some *excellent* beers. Last weekend their
Sundance Hefe-Weizen and Solstice Mystery Ale took a gold and bronze cup
in the 1996 World Beer Cup in Vail!
John Adams
- ---
Locomotive Stout
Palmer Lake Brewing Company
Palmer Lake, Colorado
Silky smooth! Roasted and very creamy! A very nice Guinness-like Irish
Stout. Not quite as heavy as it should be for the style (I would like it
a tad chewier when the weather turns cooler) but perfect for the summer.
My personal Best Of Show.
Darn Thirsty Cowboy Reserve Ale
Namaqua Brewing Company
Loveland, Colorado
Nice hoppy flavor and pleasant hop bitterness. Very smooth hop flavor and not
astringent. Very drinkable. My second favorite beer at the fest.
Ancient Whale Ale
Atlantis Brewing Company
Denver, Colorado
A hoppy beer but not overly bitter. A slightly sweet taste with a nice
bitter bite. Sort of a IPA-light.
Chili Beer
Otter Brewery???
- -- a program would have helped here
This beer has the chili flavor without the pepper heat (although it really
needs some heat). A mild ale flavor, not bad.
The Denver ChopHouse's Honey Wheat
The Denver ChopHouse
Denver, Colorado
More of the ale flavor than that of a wheat. The wheat and honey flavors
are not really present. Honey is more an an adjunct boosting the lightness.
Mild and drinkable.
Brouwer Bock
Brouwer Brewery
Loveland, Colorado
Not quite heavy enough for the style. This also tasted like an ale instead
of a lager and not smooth enough. Slightly roasted malt bite but not enough
malty flavors.
Nightstalker Ale
Back Alley Brewing Company
Colorado Springs, Colorado
While clearly an ale, the server was claiming this to be a German-style
Eisbock. Not NEARLY alcoholic enough and too malty for an Eisbock. Not
a bad beer but my expectations were set for a malty, German lager and
this was clearly not one.
Burro Daze Bock
Trout Creek Brewery
Fairplay, Colorado
The first thing I tasted was diacytle and (once again) this was not malty
enough for the style. Finishes slightly astringent.
------------------------------
From: "Dave Higdon" <DAVEH@qesrv1.bwi.wec.com>
Date: Mon, 24 Jun 1996 08:57:37 EST
Subject: potato and rice
I have a friend who was just diagnosed with gluten intolerance a few
years ago. Now she can't eat anything derived from wheat or barley
which means no beer.
Does anyone know of any recipies for a potato, rice, or any kind of
fermentable adjuncts beer?
------------------------------
From: STROUDS@cliffy.polaroid.com
Date: Mon, 24 Jun 1996 13:25:31 -0400 (EDT)
Subject: Pet 'peaves'/oxidation/acetaldehyde/bitterness of bitters
AlK sez:
> Someone (AGAIN) writes:
>
> >Belgium beers
>
> That should be BELGIAN beers! You wouldn't say Germany cars,
> America flag or France food, would you? Sorry, pet peave...
Oh yeah?? Well, my pet 'peave' is misspelling :-). 'Peeve' has three e's and
zero a's, Al.
also, back in HBD#2077, AlK wrote
>Alcohols are not oxidized to acids.
They certainly can be. Acetobacteria's preferred carbon source is ethanol,
which they readily oxidize to actetic acid (with acetaldehyde as the
intermediate oxidation product). The acetic acid in vinegar is derived from the
oxidation of ethanol.
Continuing on the acetaldehyde thread, JimDP wrote:
> Yes, if you do decide to dilute after fermentation, the dilution water must
>be handled just like beer, i.e., siphoned quietly with no splashing, to avoid
>re-aerating the water. If this is not done, the ethanol that's present in
>fermented beer will be oxidized to acetaldehyde, a very sharp flavor (green
>apples), and a very Bad Thing(tm) indeed.
and AlK responded:
> The alcohols will be oxidized to aldehydes, but not
> acetaldehyde. I've never smelled the characteristic green
> apple aroma of acetaldehyde in a beer that has post-
> fermentation oxidation. The aromas I get from these beers
> are papery, wet cardboard and PlayDough (sp?).
Ethanol will definitely be oxidized to acetaldehyde by oxygen; however, for
aldehydes, flavor threshold decreases as the chain length increases and hence
we are more sensitive to the staling aldehydes (like trans-2 nonenal) than
acetaldehyde. Another point to consider is that short chain aldehydes such as
acetaldehyde are relatively unstable and quickly under go 'aldol' condensations
to form longer chain unsaturated aldehydes.
So while I think that Jim is correct that aerating beer will cause some
acetaldehyde production, I agree with Al that it is unlikely that one will pick
up a 'green apple' aroma because of it. The cardboard and papery aromas and
flavors are generally the end result of introducing air into beer.
and finally, in the ongoing 'how bitter is Bitter?" debate, JimDP sez:
> Most of them were fairly well-balanced, so no, I don't agree
> that this is a style where hop bitterness clearly dominates.
> There are far too many counter-examples.
>
> Looking at Tim Dawson's style guidelines for English bitters:
>
> Ordinary Bitter - Mildest form of Bitter. Dark gold to
> medium copper-brown. Grain and malt tend to predominate over
> hop flavor and bitterness (although ^^^^^^^^^^^^^^^^^^^^^^^^
> ^^^^^^^^^^^^^^^^^^^^^^^^^ there are
> exceptions) with enough hop aroma to balance and add
> interest. Light to medium body. Low diacetyl and fruity-
> esters. Commercial examples: Brakspear Ordinary Bitter,
> Young's Bitter, Fuller's Chiswick, Ballard Bitter. O.G.:
> 1.033 - 1.038; Alcohol: 3 - 3.5%; IBU's: 20 - 35; SRM: 8 -
> 12. ^^^^^^^^^^^^^^^
> Yep, that's quite a range all right. I'm sure the hop
> bitterness did not clearly dominate in the examples with 20
> IBUS.
sorry, Jim, I think that you are wrong on this one. While I apreciate Tim's
guidelines, he is on the wrong track in regards to English bitters. I would
encourage you to read the excellent article that Steve Hamburg and Tony Babinec
wrote for Zymurgy (I think it was summer '95) on the subject. The gist of the
article is that Americans have a skewed perception of this style and regard it
as much less bitter than it really is (the results were based on analyses of
many English bitters).
I'll let you read the article for yourself, but for ordinary bitters in the
1.034 - 1.039 range, IBU's averaged mid to high 20's, and some were well over
30. Bitters with an IBU content under 25 were the exception, not the rule.
FWIW, the current NEHBOTY guidelines say the following about Ordinary bitter:
"....low gravity, low alcohol levels, and low carbonation make this an easy
drinking beer. The body of this beer tends to be thin, even watery. Medium to
high bitterness tends to dominate over the malt character which is usually
low...... OG ~1.034 - 1.039. 20-40 IBU."
- --Steve
------------------------------
From: John Adams <jadams@pipeline.cnd.hp.com>
Date: Mon, 24 Jun 1996 09:16:25 -0600
Subject: Lodo Brewer's Festival Trip Report
3rd Annual Lodo Brewers Festival
The Lodo Brewers Festival was held Saturday and Sunday, June 22/23 in the
shadow of Coors Field in Lower Downtown Denver. This years event was a
bit different from the past. Some of the changes were good and some areas
need a little work.
They have expanded the event to include 3 Colorado wineries (no thanks), a
meadery (yea!), and a soda 'poppery'. The Single Malt Scotch Society was on
hand providing information (but no drinks) and a local cigar shop was
selling stogies (would have gone great with a scotch).
Unfortunately the event itself needs a promotional boost. The plastic
mugs have not changed in 3 years as were the t-shirts on sale. There was
no real program guide. There was an incomplete pull-out section from last
week's Denver Post. This event hit the road running as a clone of the Fort
Collin's sponsored Colorado Brewers Fest (being held next weekend) but hasn't
changed much since.
All and all it was a pleasant day with some good brews. My personal
'Best Of Show' being awarded to Palmer Lake's Locomotive Stout. Palmer
House is a new brewery with some *excellent* beers. Last weekend their
Sundance Hefe-Weizen and Solstice Mystery Ale took a gold and bronze cup
in the 1996 World Beer Cup in Vail!
John Adams
- ---
Locomotive Stout
Palmer Lake Brewing Company
Palmer Lake, Colorado
Silky smooth! Roasted and very creamy! A very nice Guinness-like Irish
Stout. Not quite as heavy as it should be for the style (I would like it
a tad chewier when the weather turns cooler) but perfect for the summer.
My personal Best Of Show.
Darn Thirsty Cowboy Reserve Ale
Namaqua Brewing Company
Loveland, Colorado
Nice hoppy flavor and pleasant hop bitterness. Very smooth hop flavor and not
astringent. Very drinkable. My second favorite beer at the fest.
Ancient Whale Ale
Atlantis Brewing Company
Denver, Colorado
A hoppy beer but not overly bitter. A slightly sweet taste with a nice
bitter bite. Sort of a IPA-light.
Chili Beer
Otter Brewery???
- -- a program would have helped here
This beer has the chili flavor without the pepper heat (although it really
needs some heat). A mild ale flavor, not bad.
The Denver ChopHouse's Honey Wheat
The Denver ChopHouse
Denver, Colorado
More of the ale flavor than that of a wheat. The wheat and honey flavors
are not really present. Honey is more an an adjunct boosting the lightness.
Mild and drinkable.
Brouwer Bock
Brouwer Brewery
Loveland, Colorado
Not quite heavy enough for the style. This also tasted like an ale instead
of a lager and not smooth enough. Slightly roasted malt bite but not enough
malty flavors.
Nightstalker Ale
Back Alley Brewing Company
Colorado Springs, Colorado
While clearly an ale, the server was claiming this to be a German-style
Eisbock. Not NEARLY alcoholic enough and too malty for an Eisbock. Not
a bad beer but my expectations were set for a malty, German lager and
this was clearly not one.
Burro Daze Bock
Trout Creek Brewery
Fairplay, Colorado
The first thing I tasted was diacytle and (once again) this was not malty
enough for the style. Finishes slightly astringent.
------------------------------
From: Michael Mahler/Shiva Corporation <mmahler@shiva.com>
Date: 24 Jun 96 12:25:18
Subject: Tap Water
>From: Eric S Guire <esg@darkwing.uoregon.edu>
>Date: Fri, 21 Jun 1996 00:02:30 -0700 (PDT)
>Subject: Re: ANALYZE MY WATER
... water analysis omitted:
>I was suprised to find that my tap water was consistantly cleaner than
>the values you reported for your filtered water. I guess it just goes to
>show, water sources around the country varry alot!
Actually, you can't say your water is any "cleaner" than his, but it IS VERY
SOFT!
This anaylsis didn't include the typical ogranic and non-org contaminants that
you would find in tap water and I suspect if his carbon filter is decent
quality, those levels would be lower than yours, if you have any that is.
But Eric does indeed have some great base water to start playing with!
------------------------------
From: Kerry Drake <drakes@oklahoma.net>
Date: Sun, 23 Jun 1996 22:29:58 -0500
Subject: Bitter?
Al Korzonas wrote:
Ahem... recall that one of these flavourful, low-gravity styles we're
talking about here is English Bitter? This is a style where bitterness
should clearly dominate.
During my all too frequent trips to various parts of the world, I almost
always stop in Mildenhall, England. Since we usually only have about 24
hours on the ground, I settle for what's in the fridge when I get to my room
(on a U.S. airbase, they know what we need!) usually John Bull Bitter. It
has a less bitter taste than most Pale Ales that I've had. I've not had any
other -Bitters- to compare though...
Kerry Drake
------------------------------
End of Homebrew Digest #2080
****************************
