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HOMEBREW Digest #4762
HOMEBREW Digest #4762 Thu 21 April 2005
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
Memphis in may, Beer Man Microbrewery (wmkolb)
re: solvent flavors/email address ("-S")
strange fermentation (leavitdg)
Cutting Kegs ("Martin Ammon")
Phil's Mill Motorizing (Randy Pressley)
re: Subject: Some questions ("Michel J. Brown")
re: Subject: Kettle Braid ("Michel J. Brown")
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Date: Thu, 21 Apr 2005 00:02:47 -0400
From: wmkolb at comcast.net
Subject: Memphis in may, Beer Man Microbrewery
Hey All. I have not posted in 2 years. Looks like the old' HBD has
slowed down a bit. Anyhoo. I'm Wil. Used to post her some. I used to
own the Happy Dog Brewing Supplies and then The Beer Man In Mt.
Pleasant SC. Just wondering if any of you guys have ever been to
Memphis in May. I told a buddy of mine he should look into getting in
to Memphis in May and dammed if he didn't make it! In turn he asked me
to go with him. So I'm looking at 4 days of BBQ, Beer and FUN. Anyone
ever been? Got any pointers? Any thing we have to see? Do?
A favor. Any of your friends just have to have a Mr. Beer or Beer
machine and you want them to have something better, please point them
my way. www.beermanmicrobrewery.com
Wil
The Beer Man of SC
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Date: Thu, 21 Apr 2005 01:55:44 -0400
From: "-S" <-s at adelphia.net>
Subject: re: solvent flavors/email address
A. J. deLange answers the major point of the "solvent-y" aroma question.
>Solvent like flavors and aromas are usually associated with ethyl
>acetate
There is no doubt at all on that point - nail polish remover.
>- the ester most commonly found in beer because there is lots
>of ethanol and lots of acetate involved in the metabolism of fermenting
>yeast.
I suspect AJ knows this well, but the mystery isn't why ethyl-acetate levels
are high, but why they aren't a lot higher given the sea of ethanol and
acetyl-CoA precursors. Esters in beer are largely formed from alcohols
(ethanol and fusels) and a fatty acyl-CoA in a two step enzyme mediated
reaction. The final step involves the fatty acyl-CoA reacting with the
alcohol, catalyzed by an alcohol specific alc-acyl transferase enzymes. The
yeast's genetics determine which of these transferase enzymes are produced
and their alcohol affinity and this regulates (to a great extent) ester
aroma character of that yeast.
Though acetyl-CoA is the most abundant fattyCoA as it's produced by several
metabolic steps, also the fatty acid synthesis and oxo-acids from protein
synthesis will result in other variant acylCoA.
The reaction:
Ethanol + AcetylCoA => EthylAcetate
has the most abundant alcohol reacting with the most abundant acylCoA, so it
could cause an abundance of nail-polish aroma in beer except for the fact
the ethanol acyl-transferase enzyme is not so abundant or active in brewing
yeast.
Still EthylAcetate is the most abundant ester in beer, but at 5 to 25ppm
typical and with a flavor threshold around 33ppm it is not a major flavor
factor. Various IsoamyAcetate ester isomers give banana or pear aroma and
can appear in ales at 0.5 to 10 ppm (or even more) with a threshold around
1.5ppm - this ester can be a major flavor factor.
So oddly, ester formation is dependent on yeast genetics and the presence of
fusels oils (higher alcohols) ! Also it takes energy to produce esters
making one wonder why yeast bother.
>Higher alcohols usually have, IMO, more floral, sweeter aromas
>and the other esters I would describe as fruity or berry like.
I agree with the ester assessment, but I'd call the first impact of higher
alcohols "ethereal". They have a "spirity" character which is obvious when
you first exhale. They often have a warmer and "higher pitched" note
above the ethanol and sometimes an herbal basil or anise-like note, and they
add a raspy finish at the back of the throat. My sense of taste may be
peculiar, but I often sense a "dumbing" of the mid-tongue and even an
unpleasant mid-tongue bitterness when fusels are abundant.
There are many fusels from several sources, but as a rule the flavor active
fusels appear then amino acids are either plentiful or in short supply. A
major exception here is glycerol(aka glycerin) which is sweet, adds body but
little flavor and is produced in abundance (up to 2000ppm) by yeast. The
flavorful fusels usually are derived from oxo-acids which pool during growth
phases when either aminos are abundant (by transamination of consumed
aminos) or by synthesis during low amino acid growth. Some oxo-acids are
decarboxylated to form an aldehyde, then the aldehyde is reduced (another
energy loss) to a fusel alcohol.
Never forget that this same general process produces ethanol ! Pyruvic acid
is decarboxylates to acetaldehye which is the energetic end-point of
fermentation. Yeast are forced to reduce acetaldehyde(energy loss) to
ethanol to maintain their internal redox-balance and avoid dying of terminal
heartburn.
So the amino acid:
leucine relates to 3-methylButan-1-ol, an isoamyl alcohol
valine to isobutanol
isoleucine to 2-methylButan-1-ol
phenylalanine to phenethyl alcohol (a rose-like aroma)
tyrosine to tyrosol
...
Fusels are formed when the oxo-acids get involved in these processes of
aldehyde forming decarboxylation and that doesn't happen as much when cell
membranes are replete with sterols and UFAs and at lower temperatures.
Underpitching, underoxygenating, high gravity fermentation adding excess or
insufficient amino acids and too-warm fermenting encourage fusel formation.
Esters are formed primarily mid to late in fermentation as the yeast lipid
synthesis slows/stops. The yeast have to detoxify the short fatty acid
fragment left over by esterification and this same procedure then applies to
fusels. Of course many esters are derived from corresponding fusels, but
yeast genetics are the primary gating factor on the relative levels. There
is some odd but unclear relationship between lipid synthesis and ester
production. Adding a bit of linoleic acid (50ppm) reduces ester levels
dramatically, tho' researchers think this somehow prevents the expression
(not the activity) of the alcohol transferases. One can clearly encourage
ester (and fusel) formation with high temperatures, but the impact of growth
and oxygenation on esters often give anomalous experimental results.
I think the characterizations relating fusels and esters production to
"yeast growth" are impractical and even a bit bogus. If you have wort with
a certain amount of fermentables then any competent fermentation will use
95+% of those fermentables during a yeast growth phase. You can reduce
the total yeast growth amount a little by vastly overpitching, but that's
not a realistic brewing method. Yes, higher growth rate can be directly
related to all sorts of by-products rates, but at the end-of-fermentation
there is no decent alternative to having sum total yeast growth nearly
proportional to wort fermentables.
The original query asked for examples ... no beer has much in the way of
EthylAcetate flavor I hope. For isoamyl esters try a good fresh German
style pale weizen with a big banana & bubblegum nose. I taste fusels all
too clearly in most high alcohol beers. Sierra Nevada Bigfoot clearly has a
significant fusel component - unmistakable.
===
Some time ago an HBDer courteously complained that my email reply address
was invalid. He was wrong. RFC0821/RFC0822 are the applicable standards
which define email protocol. The email address: <-s at adelphia.net> is
perfectly valid according to those standards. The name field ("local-part"
of RFC0822) may include the hyphen, plus, underbar and many other printable
ascii punctuation characters in any position. See
ftp://ftp.rfc-editor.org/in-notes/rfc822.txt for the gory details.
If your mailer doesn't accept this valid address you should certainly
complain to the vendor. You *may* find that double-quoting the local-part
field is a workaround for a defective mailer as this is an accepted method
of preventing interpretation of special characters (tho' hyphen is not
actually a special character). Try <"-s" at adelphia.net> if your mailer
is broken.
-SteveA
------------------------------
Date: Thu, 21 Apr 2005 06:17:21 -0400
From: leavitdg at plattsburgh.edu
Subject: strange fermentation
Did you re-hydrate the yeast, and, are you watching the temperatures of the
fermenter? Depending on the yeast that you used, a little too low temp and it
will not be happy.
Darrell
------------------------------
Date: Thu, 21 Apr 2005 07:17:18 -0500
From: "Martin Ammon" <SURFSUPKS at KC.RR.COM>
Subject: Cutting Kegs
Mike
I cut the kegs for the brewing systems I build with a plasma cutter. I
cut the rolled top edge off just above the handle opening leaving the
handles. The next cut I cut an opening in the top lager enough to get my
hand and torch inside the keg than I cut the top off from the inside just
about the top weld. With a little grinding on the top edge and the edge on
the in side you in up with a keg straight sided from top to bottom. I make
the make the false bottom from Performated stainless steel in appox 15 dia.
circle. (all kegs are not the same in size or completely round ) some large
as 15 3/32. Tig weld a handle, drill a hole center for the pick up tube and
your done. The false bottom is out of 18 gauge 1/16 hole 1/8 spacing which
is cut with the plasma and a compass set up. I like the straight sided kegs
but have used some of the older style kegs what are larger in the center but
with same cutting.
Lids are made out of stainless and cut to the size of the opening a touch
larger. But I also have lids on one of my systems made out of plywood than
wrapped in the foil insulation and foil tape.
Hope this helps
Kansas Swagman
Its Never Too Early Only Late
------------------------------
Date: Thu, 21 Apr 2005 06:41:28 -0700 (PDT)
From: Randy Pressley <randypressley at yahoo.com>
Subject: Phil's Mill Motorizing
I'm curious as to why there is a warning in the manual
about not motorizing the Phil's mill? When I started
doing 10 gallon batches I decided to dangerously
motorize my Phil's mill. I took a hack saw and
positioned it as close as possible to the handle
and off came the the handle with just a few strokes.
What I had left was a 1/2 inch nub. I attached
my drill to it and it worked like a champ. I've
been using it now for over 10 years. I've also
found that instead of using a plastic 2 liter bottle
for the feeder I use one of those large plastic
funnels that is normally used for filling the carboy.
It works perfect and holds about 8lbs of grain.
Cheers!
------------------------------
Date: Thu, 21 Apr 2005 11:20:24 -0700
From: "Michel J. Brown" <zymurgyst at comcast.net>
Subject: re: Subject: Some questions
>Michel Brown, I have some questions.
Lord willing, I may have some answers, John, and hopefully they will work
for you as well.
>When you say diacetyl is produced by delayed cooling, do you mean
>dimethylsulphide?
Well, actually, there's both; DMS *and* diacetyl are both formed from slow
cooling in a closed container in which the evaporant condenses back into the
wort during cooling. Diacetyl is formed mostly at the lower end of the
temperature range, while DMS is at the higher end of the range from my
personal experience. The precursors to both DMS and diacetyl are sometimes
from the same family, just different energy levels.
>I've never heard of diacetyl being caused by delayed chilling.
That's probably due to the fact that most home brewers use some kind of wort
chiller, and therefore do not see that happening. Let the wort chill to
pitching temp during the summer while covered, and you'll see what I mean!
>I've also not found DMS to be a problem when I steep my hops for half an
>hour or so in a covered kettle, as long as the boil is sufficiently active,
>and un-covered.
Is it covered or uncovered? I'm not entirely sure what you mean here, guess
my CFS is taking its toll again. But if you mean what I think you mean,
that you are steeping finishing hops in the kettle after the boil for 30
mins covered, after being boiled UNcovered, then you may or may not
experience problems. The main factors here are malt variety, kettle
geometry, and how vigorous a boil you have (as in how many times it rolls
over).
>Air in system - I'm afraid I'm ignorant - can you explain breakout and its
>effects further?
Well, I'm ignorant too, just in different areas! Breakout of gases from
solutions, especially air in water occurs as water naturally contains a
great amount of entrained air. Most faucets have aerators on them due to
the fact that aerated water tastes better to most people. The downside is
that when you heat up this water, it starts to give up this air to the
atmosphere in a direct proportion to the heat energy applied. After time,
the entrained air will be released from solution to the atmosphere, but in a
sealed system, like what Mike Eyre was talking about, there's no real place
for the air to go, so it forms bubbles, or an embolism in the lines,
preventing the flow of liquid water.
>Mashing - What do you gain from hours of mashing and sparging?
Hours of mashing not only ensures complete conversion, it also develops
flavor profiles that enhance the malty flavors more IMHO. I do not know the
biochemical pathways involved, but I can attest to the fact that with longer
mashed brews (to a point), the malt flavor becomes more pronounced. As for
long(er) sparging times, this simply is to extract the maximum amount of
extract from the grist. I've never had problems with harsh or astringent
flavors from what others say can lead to tannin extraction. I keep my wort
at an acidic enough pH that this is really a moot point.
>Do you really notice much difference compared to an hour of mashing and
>half an hour to an hour of sparging? If so, what are the differences?
As I stated above, its mostly in flavor development. I experimented with
different mashing and sparging times, and found I get the most flavor from a
relatively long mash at a relatively low(er) temperature. I also find that
I get a much higher extract rate going to a relatively longer sparge over a
shorter 45 minute sparge as recommended in most home brew books. I think
they say these things to prevent people from being scared off from all grain
brewing, since most people don't have the patience, or temperament to handle
these longer times.
>I think maybe you're not noticing ill effects of counter-pressure filling
>because of the kind of beer you're bottling. It appears to me that beers
>with lots of hop flavor and aroma are the >ones that suffer the most
>damage.
That's possible, since I brew a lot of big brews, mostly Belgian and German,
and a few British as well. But that doesn't explain my Russian Imperial
Stouts, nor my Barleywines, which are VERY hoppy, yet retain wonderful
flavors up to 15 years after they were bottled.
>Diacetyl-related flavors and oxidized flavors can definitely arise in very
>hoppy beers that are CP bottled. Massively malty beers have massive
>flavors (and, generally, not a lot of hop subtlety) and I doubt that they
>would suffer as much as the more delicate styles.
This sounds like a perfect time for the Great American Zymurgist Experiment
(aka GAZE)! Perhaps there is a relationship between maltiness and hoppiness
where the datapoints coincide to pathways that say diacetyl (yes/no) in a
CPBF environment? My beers usually and customarily have *both* malt AND hop
character, which I am constantly being asked how do I do it, and what are
they doing or not doing to make beers with both malt and hop character. All
I can say is that unless you brew together, no amount of armchair brewing is
going to resolve the dilemma. I feel that its the procedures and the
ingredients and how they are used that make for the particular brew being
made at the time. Consider this: professional brewers in Germany have a
brewing cycle that allows for them to make 2-3 brews per day, with overlap
of the brewing cycle to allow for mixing and blending their product at
various points along the mashing and fermentation cycle. They make beers of
extraordinary complexity and depth, yet they practice procedures poo-poo'ed
by the rest of the world, even though the results they get can't be
reduplicated in any other way. A case in point: first wort hopping; I've
been using this technique for the past 20 years, and have found it does
amazing things for hop character, yet I see very few home brewers even
trying it, let alone talking about it. Why don't the HBD'ers start an
experiment with three beers: one light bodied, one medium bodied, and one
full bodied, all with the same (relatively high) hop charge, then keg the
results and CPBF a random sixer from each brew for evaluation. Too, another
experiment would have to be performed to make three brews exactly alike, but
with three different hop charges (maybe a blend of the three worts from the
first part of the experiment?) so that we could map the datapoints in
relationship to the hop character for a given malt extract. I hope I
answered your question, but as far as I know, I've never seen a beer that
I've CPBF, hoppy or not, develop any signs of diacetyl. Maybe this is due
to the fact I purge my system and bottles of air with CO2, and the liquid
line with beer before bottling. I'd like to hear what others have done or
found that works for them in this regard.
Prost!
Michel
Somewhere in the unfashionable eastern end of Mutter's Spiral in the Milky
Way
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Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.1 - Release Date: 4/20/2005
------------------------------
Date: Thu, 21 Apr 2005 11:37:08 -0700
From: "Michel J. Brown" <zymurgyst at comcast.net>
Subject: re: Subject: Kettle Braid
>G'day all, Speaking of kettle screens...
Good day, Rowan! How's the home brew scene in your area of Australia?
>I'm putting together a sankey shaped kettle and I've got some braided hose
>that I want to use as a giant bazooka for screening out break and pellet
>mud
>prior to racking through my CFWC and on to the fermenter.
I take it you are going to be using unlined braided SS hose, right?
>Has anyone had any problems with simply laying the braided hose (called a
>"happy hooker"
>here in Oz) around the inner circumference of the keg, er, kettle? If I
>whirlpool the boiled wort >and let it sit for 30 mins and then transfer,
>I'm hoping to minimize the goo in the brew.
A friend of mine does just that and it works for him. The caveat if I
recall correctly was that he had to use a lot of braided unlined SS hose to
do what you're planning. It looked like a spiral with a center draw off to
the drain, and the outside end was simply blinded off.
>My only concern is the boil...Will the hose present a risk of trapping and
>burning grain particles or >pellet matter under it during the boil or am I
>being overly concerned?
Well, my brewing buddy hasn't had any problems like that, just slow runoff
till he added sufficient length to the hose. I feel that a simple wire mesh
screen tube works just as well, albeit not for pellets as they will plug a
screen right away, but for whole flowers, I get a perfectly clear wort each
and every time, no whirl pool needed! The only concern I have is what kind
of heat source do you use? My partner uses a ring burner, and I use a jet
burner with a deflector plate, and neither of us have ever had any problems
with scorching, burning, or entrapment of break residue.
>Cheers,
>Rowan Williams
Prost!
Michel
Somewhere in the unfashionable eastern end of Mutter's Spiral in the Milky
Way
- --
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.1 - Release Date: 4/20/2005
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End of HOMEBREW Digest #4762, 04/21/05
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