Copy Link
Add to Bookmark
Report
HOMEBREW Digest #4846
HOMEBREW Digest #4846 Tue 13 September 2005
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
***************************************************************
THIS YEAR'S HOME BREW DIGEST BROUGHT TO YOU BY:
Northern Brewer, Ltd. Home Brew Supplies
Visit http://www.northernbrewer.com to show your appreciation!
Or call them at 1-800-681-2739
Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********
Contents:
Re: Using chest freezer ("Michael O'Donnell")
Chlorphenolics ("A.J deLange")
Re: photodecomposition of beer (Jeff Renner)
Re: Hops (Jeff Renner)
photodecomposition of beer ("Peter A. Ensminger")
Announcement: MHTG 2005 Franco-Belgian Challenge Cup (Eric Schoville)
More on flasks ("Peed, John")
Kunze and searching digests (Signalbox Brewery)
Re: more esters, and also acids 1/2 ("Fredrik")
Re: more esters, and also acids 2/2 ("Fredrik")
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* The HBD Logo Store is now open! *
* http://www.hbd.org/store.html *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Suppport this service: http://hbd.org/donate.shtml *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Beer is our obsession and we're late for therapy! *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Send articles for __publication_only__ to post@hbd.org
If your e-mail account is being deleted, please unsubscribe first!!
To SUBSCRIBE or UNSUBSCRIBE send an e-mail message with the word
"subscribe" or "unsubscribe" to request@hbd.org FROM THE E-MAIL
ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!**
IF YOU HAVE SPAM-PROOFED your e-mail address, you cannot subscribe to
the digest as we cannot reach you. We will not correct your address
for the automation - that's your job.
HAVING TROUBLE posting, subscribing or unsusubscribing? See the HBD FAQ at
http://hbd.org.
LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go
instead to http://homebrewfleamarket.com and post a free ad there.
The HBD is a copyrighted document. The compilation is copyright
HBD.ORG. Individual postings are copyright by their authors. ASK
before reproducing and you'll rarely have trouble. Digest content
cannot be reproduced by any means for sale or profit.
More information is available by sending the word "info" to
req@hbd.org or read the HBD FAQ at http://hbd.org.
JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning,
and Spencer Thomas
----------------------------------------------------------------------
Date: Mon, 12 Sep 2005 22:13:37 -0700
From: "Michael O'Donnell" <mooseo at stanford.edu>
Subject: Re: Using chest freezer
Aaron wants to use a chest freezer cooled by a dorm fridge as a
fermentation chamber:
I was planning on doing this, but it turned out that the freezer getting
thrown out at work merely had a cracked power cord (score!) so I used it
for serving instead.
What I did for a fermentation chamber was even more of a kluge than you
propose and it worked fine. I built a box out of foam insulation with a
hole in the side, took the door of the dorm fridge and duct-taped it into
the hole. I built a box big enough for 4 corny kegs and it could keep it at
50 F if needed. With the better seal from a freezer, I suspect that it
could lager.
To keep it warm in the pansy winters we get in California (ooh, it's below
40, what do we do?) I bought a little de-humidifying heater... these are
stick heaters of about 20 W... I like them because they just can't generate
enough heat to ruin anything if the temp controller messes up. In
Michigan, it would probably freeze solid.
I would recommend that you get a little more creative with the temperature
control, however... There will be a lot of cool air in the fridge when the
temp control clicks off that will be wasted because the fans will go off at
the same time... what would be sweet is 2 controllers, one for the fridge
and one for the fans... or, maybe just put the fans on the controller and
fill the fridge with bottles of cold water... let the fridge stay on all
the time keeping the water cool and just blow air when the chest freezer
gets to warm.
The only problem I had with my arrangement was a lot of condensation from
keeping it at 60-65... Since I only ran it for a few weeks at a time, I
didn't worry about it, just put a bowl under the chill plate in the fridge.
Your system will be much better sealed than mine was, and this problem will
probably be less severe. Maybe put some de-humidifying crystals in there,
or don't worry about it.
As for which would be more efficient, define efficiency... in terms of
saving electricity, yes, buying a new Energy-star fridge will be more
efficient, but maybe not enough to worry about. I don't end up brewing as
often as I like, so the fridge isn't really on that much. If you are
talking about efficiency in construction, again, probably, but it sounds
like a fun project and if you want efficiency, you could just buy beer.
Let me know how it goes... my setup didn't survive my recent move, so I
will need to recreate it... I'm thinking of doing exactly what you are
proposing next time.
cheers,
mike
Formerly, Monterey, CA, now Santa Barbara, CA
------------------------------
Date: Tue, 13 Sep 2005 12:46:50 +0000
From: "A.J deLange" <ajdel at cox.net>
Subject: Chlorphenolics
The water is the most likely source. You can obtain simple, inexpensive
test kits from aquarium supply stores or water testing suppliers
(Lamotte, Hach) which will enable you to test your incoming water for
the presence of chlorine and chloramine (be sure you get a kit which
lets you measure both). An even simpler test is to draw a glass of water
and let it stand over night. If it still smells of chlorine the next day
that's a pretty good indicator than chloramination has been used. If you
pour the water back and forth between two glasses and chlorine odor
persists but goes away when a bit of crumbled Campden tablet is added
that's also a pretty good indication that chloramine is in use. You can
also call the water company and ask if they chloraminate.
Given that you have chloramine the easiest way to get rid of it is to
add a Campden tablet (crushed) to 20 gallons of tap water. This is
usually sufficient but if it still smells of chlorine after treatment,
add another half tablet. Keep doing this until the water doesn't smell
of chlorine. If beer brewed with water treated thus is free of
chorphenolics they you have found and solved your problem.
RE decarbonation: Home ion exchange water softeners do strip out Ca and
Mg and replace them with sodium. This is not generally regarded as a
good thing to do to brewing water. Rule of thumb: hardness = good,
alkalinity = bad. These softeners strip hardness and leave alkalinity
untouched. Furthermore, it is more difficult to remove alkalinity after
a trip through the softener because the stuff that precipitates the
carbonate (Mg, Ca) must be put back in in the form of calcium (and/or
magnesium) salts or lime. If the starting water had a lot of temporary
hardness and you added enough calcium chloride to get most of the
carbonate the water is going to be salty because the softener has added
sodium equivalent to the bicarbonate and you've matched it with an
equivalent amount of chloride. So skip the softener and decarbonate with
lime or by boiling. Some calcium supplementation to augment carbonate
and later (in the beer) oxalate precipitation is fine.
As for the hose: go to an RV supply store or ships chandlery and buy one
of the hoses they sell for shore water hookup. These are flavor neutral.
------------------------------
Date: Tue, 13 Sep 2005 09:27:54 -0400
From: Jeff Renner <jsrenner at umich.edu>
Subject: Re: photodecomposition of beer
"Peter A. Ensminger" <ensmingr at twcny.rr.com> wrote from
Syracuse, NY:
> A recent review article ... discusses recent research on the
> mechanism of
> the flavin-mediated light-struck reaction, which leads to formation of
> 'skunky' mercaptans following exposure of beer to blue light.
Thanks, Peter. I understood the introduction and conclusion. The
parts in the middle?
One passing assertion jumped out at me because I had never heard the
claim, and it is not attributed, despite ample footnotes throughout
most of the article:
> Moreover, health-beneficial properties due to particular compounds
> present in hops confer to beer a unique position in the
> appreciation of (low-)alcoholic drinks.
Now, as much as I'd like to believe this, I'd like to have some
substantiation. All I've ever heard is that hops can make you
sleepy, but I haven't seen any scientific investigation into this. A
quick google of health benefits of hops turns up only anecdotal
herbalist kinds of claims of hops relaxing or sleep-inducing
qualities - again, nothing I'd want to include in a scientific paper.
Anyone know more about this assertion of "health-beneficial
properties" of hops?
Jeff
- ---
Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu
"One never knows, do one?" Fats Waller, American Musician, 1904-1943
Calculate your Rennerian Coordinates at http://hbd.org/
rennerian_table.shtml
------------------------------
Date: Tue, 13 Sep 2005 09:34:34 -0400
From: Jeff Renner <jsrenner at umich.edu>
Subject: Re: Hops
Bill Frazier <billfrazier at worldnet.att.net> writes from Olathe,
Kansas USA :
> I've spotted some wild hops growing near my house. When are hops
> ready to
> pick? What are signs of hop flower maturity? Thanks.
It's likely too late, at least based on hops here in SE Michigan,
where the season is probably a little later than Kansas. They are
ready when they are somewhat dry and papery feeling but still green.
IIf they crumble when you squeeze them, they are perhaps too dry.
They shouldn't be brown at all.
The next question you are probably asking is, "What kind are they?"
Ralph Olsen of HopUnion has told me that in (nearly?) all of the
cases in which they have identified wild hops sent into them, they
have turned out to be some variety of Cluster. I don't know if this
is because they are escapees or if the indigenous hops or N.A. are
that close to Cluster.
Jeff
- ---
Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu
"One never knows, do one?" Fats Waller, American Musician, 1904-1943
Calculate your Rennerian Coordinates at http://hbd.org/
rennerian_table.shtml
------------------------------
Date: Tue, 13 Sep 2005 10:53:29 -0400
From: "Peter A. Ensminger" <ensmingr at twcny.rr.com>
Subject: photodecomposition of beer
Regarding the statement, "... health-beneficial properties due to
particular compounds present in hops confer to beer a unique position in
the appreciation of (low-)alcoholic drinks" in the recent Huvaere &
Keukeleire paper (see: <http://www.hbd.org/hbd/archive/4845.html#4845-1>)
I would guess this is a 'throw-away' line. However, there has been
extensive study of the effects/benefits of xanthohumol (a prenylated
chalcone present in hops). Do a search for xanthohumol in PubMed:
<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi>. Numerous preclinical
studies demonstrate anti-tumor/chemopreventative action and several
other potentially beneficial effects. This may be because xanthohumol
acts as a potent anti-oxidant. I could not find any clinical studies on
hops or xanthohumol.
Nevertheless, I'm still waiting for my doctor to say, "take two beers
and call me in the morning"
Cheerio!
Peter A. Ensminger
Syracuse, NY
Beer data: http://hbd.org/ensmingr/
------------------------------
Date: Tue, 13 Sep 2005 10:58:48 -0500
From: Eric Schoville <eric at schoville.com>
Subject: Announcement: MHTG 2005 Franco-Belgian Challenge Cup
The Madison Homebrewers and Tasters Guild are pleased
to announce the 2005 Franco-Belgian Challenge Cup.
The contest is an attempt to encourage the homebrewing
of French- and Belgian-style beers. As such, only
French- and Belgian-style beers (BJCP Categorys 16-18)
will be judged. The competition is sanctioned by the
AHA and BJCP. AHA/BJCP 2004 Style Guidelines will be
used. The contest will be held on 11/5/05.
Additional information is available at our website:
http://www.mhtg.org/contests/MHTG%20Contests.html
------------------------------
Date: Tue, 13 Sep 2005 11:39:45 -0700
From: "Peed, John" <jpeed at elotouch.com>
Subject: More on flasks
John Shnupp comments on starters in Erlenmeyer flasks. While I agree
that they're prone to boil-overs and foam-overs, the beauty of doing it
all in the flask is that you minimize equipment, transfers and general
handling. I boil on a gas stove, so hadn't thought about the perils of
electric stove eyes. In general, you want to boil slowly and carefully.
Likewise, you're pushing it if you try to decant and then juice the
starter a second time - active yeasts like 1056 will usually foam right
out the top. It might be best not to decant and re-juice - there's a
lot to be said for keeping the system sealed and undisturbed until it's
time to pitch. As for the foam stoppers, the seller claims that they
will filter any contaminants/bacteria/yeast, and I have found this to be
true; I've been making starters with foam stoppers on a stir plate for a
while now and they come out clean. One thing that does not seem OK to
me is to splash or otherwise introduce unfiltered air into starters or
wort. The foam stoppers appear to work as advertised. After each use,
wash sanitize in iodophor, then wring out the excess. As for cooling, I
have always put the flask in a sink of cold tap water filled to the
depth of the wort. After a few minutes the now warm water is replaced
with ice water. Works fine, although I wouldn't push it by putting it
in the freezer. I know that borosilicate glass is not completely immune
to temperature shock because I shattered a hot quart measuring bowl once
by setting it on a cold stainless countertop, but the lab glass stuff is
high quality and should tolerate such things. What it won't tolerate
very well is bumping, dropping and that sort of thing, as I've proven
way too many times ...
Again, the advantages of this starter "system" are: boil, cool, and
fermentation all take place in one container, with no transfers; the
container can breath while still protecting the contents; the stirring
action pulls filtered air into the starter, reducing the time required
while at the same time stimulating more yeast growth (most people agree
that you get about twice as much yeast this way).
John Peed
Oak Ridge, TN
------------------------------
Date: Tue, 13 Sep 2005 21:30:32 +0100
From: Signalbox Brewery <signalbox.brewery at ntlworld.com>
Subject: Kunze and searching digests
Two questions:
There used to be a certain enthusiasm for Kunze's
Technology Brewing and Malting round these parts.
I haven't seen any mention for a while and yet there
seems to be a new edition out "3rd completely
updated english edition of "Technologie Brauer
und Maelzer" - Published November 2004" according
to the VLB's website.
Are folk as fond of the new edition?
Secondly I did try to answer the question through the
hbd search page http://hbd.org/cgi-bin/hbdindex.cgi/hbd_index
However I can't get this to return anything using either
Mozilla Firefox or IE6. Any tips?
David Edge
------------------------------
Date: Tue, 13 Sep 2005 22:32:37 +0200
From: "Fredrik" <carlsbergerensis at hotmail.com>
Subject: Re: more esters, and also acids 1/2
Dang, this formatting and 8k limit again. not sure if this gets readable.
- ---
The ester discussions are interesting.
I really don't have much to add, and I kind of
agree with what has been said that insisting on
finding simple answers to complicated questions
makes it even harder, if not impossible. But I can't
resist throwing out some more ideas to feed the discussion.
I apologize if it's foggy.
I think there are possibly many ways to attach this, but
I personally like to think this a bit like this from
a modelling point of view:
- I picture the cell as collection of pools. Each
compound in a certain cell department
is represented by a pool, and clearly each pool has
a level.
- All pools are cross-connected via a huge number of
pathways. Each pathway has a well defined impact on
the other pools as determined by the stochiometry.
- But the specific rate of each pathways is part of the
biological regulations. The rates depends
on the type of reaction kinetics, but ideally
reactant and product pools as per som standard
mechanisms, as well as some enzyme pool and enzyme
regulations.
So given that we assume simplified standard kinetics,
it boils down to enzyme regulations and enzyme
pools - for each pathway.
So far - it would be a matter or mapping out the
pathways and pools, and implementing the necessary
numerical routines to find the pool dynamics.
But, the point where I find it gets almost overly
hairy (supposing the computational problem wasn't
hairy enough) is that how are these enzyme
levels and acitivites regulated? Where are the rules
for that?? Here it becomes evident that there is a
living organism behind all this. So understanding how
these enyzymes are regulated seems to require
understanding the organism needs on a system level
rather than molecular level?
So to me, the practical question is not what molecular
mechanisms yeast uses to pull off the regulatory task, it's why
(ie. to maximize survival, and reproduction etc).
How, would probaly get us down to details where I
for one would get totally lost. So instead of
asking how, I only want to know why, and
hopefully use it as as shortcut.
As I posted about before I started this fun but
never ending project of a fermentation simulation a couple of
years ago, and the while I think some progress is
made, the closer I think I get the more do
I realize that it's not good enough, and I keep
revising the strategy without moving much forward.
I have found no other way out but to adapt some of the
nice approaches used in some of the simualtions
that has been done.
It leaves a set of pools, set of pathways,
and for each pathway a set of parameters. Parameters
that the organisms tweaks/expresses in order to attain
their goals of life, and I don't even want to know
How it's done. I just trust that after billions of
years, it's figured it out. It's like the game of
life, put in the rules, sit back and watch.
Now the brute force way of finding the regulation
output, given the goals (next problem), would probably
require more computing power than the rest of the
simulation. So right now, I'm hoping to find a
clever way to do the task with less computing power.
This is where I'm stuck fiddling atm. This turns out
to be a very realistic problem since you never have
infinite computing power in reality.
I decided for myself that it can't be made much simpler than this,
at least not in the general case?
> 1. I think pitching rate affects total growth ONLY because of the
> small amount of energy required for (non-growth-related) background
> maintenance of the cells. Posts (I recall some by Steve) in the
> archives suggest that this is a pretty small amount of energy and hence
> total growth should not change dramatically with pitching rate. But if
> there is a pool of Acetyl CoA laying around after growth stops, and AAT
I'm a little doubtful on this.
No doubt there is maintenance, and more cells => more maintenance. But
I would also expect, that the specific(cellwise)
maintenance per cell would increase significantly
as the health drops. Low pitching rate, low aeration
and I would suspect that the cellwise total
maintenance cost to be higher than that of a more
healthy cell?
I would love to see data on this though. I haven't found that
much, so I have missed something interesting. I know
I have seen once a test indicating that more yeast ->
less total biomass growth, but that was carried out by
pitchting rates that I'd consider to be overpitching and
lots of details was missing, also the difference was not that big.
I suspect that if you add the order of a yeast cake then the story is
probably different than if you compare 0.13 vs 1
million/ml/P? A big crappy yeast cake would probably
require more *initial* maintenance though?
/Fredrik
------------------------------
Date: Tue, 13 Sep 2005 22:32:40 +0200
From: "Fredrik" <carlsbergerensis at hotmail.com>
Subject: Re: more esters, and also acids 2/2
> 2. IS there a pool of Acetyl CoA lying around after growth stops?
Growth doesn't *stop* completely until it's time to go dormant,
but it slows down
But when there is still growth, but the limiting
factor limits the consumption of acetyl-CoA (like
Steve wrote in the other response), the steady-state
pool of acetyl-CoA increases. At some point the
production got to be downregulated a bit because if
the production is higher than consumption it wouldn't
only pool, the poole level would just keep increasing, and
that makes no sense. It also makes no sense
to keep bleeding at full speed? But from the
"downregulate" command to realisation there is
probably a temporary excess pool level levels that
has to bleeded off by other pathways. But even after
this temporary pool-peak, the pool level will
probabably reach a steady state value that is alot
higher than during high growth, so there will be bleeding
still.
One question is, how fast the atf enzymes
can arrive from the point where they're requested?
would they risk miss the first peak or not? ie.
would the atf enzyme level be higher after the peak
than before? Depending on enzyme timings and their
deactivaton rates, Perhaps a way to increase esters,
might be to have the growth conditions "oscillate"
from the early parts, in order have the
"downs" stimulate enzyme synthesis and catch
the coming acetyl-CoA peaks better? And I'd just
guess that the enzymes downregulate slower than
they upregulate? Just an idea. Not sure what would
be the best wat to do that though but it sounds like
a fun experiment.
With really high pitching rates, the growth would keep
the acetyl-CoA pool low for a a dominating part of
relative consumption, and the population would probably
consume less sugar while in the "high acetyl-CoA pool
state", and thus the potential for ester synthesis
lower? and once the drop finally comes, it's pretty
much over. With a lower pitching rate, or poor aeration
the consumption of acetyl-CoA due to growth would
proabably drop much earlier probably due to low
quality membranes, relative to the % of total sugar
consumed.
John Palmers idea sounds like the triggering condition
for enzyme synthesis among other tings is the
acetyl-CoA level which is plausible. If I am not
mistaken I think I ready somewhere that specific atf
enzymes are also induced by precense of fuesels too.
So I still wonder exactly what regulates the enzyme
levels. I assume the reason for the ester synthesis
overall is a kind of regulation, and it would seem
logical to alert this response system when the need
for regulation becomes apparent(the signal), but not
sooner? Can we even understand yeast by common
sense logic?
It's a pity Freud and Jung wasn't brewers or I'm sure they would
have explained the yeast response patterns ;-)
> 3. Do fatty acids ever leave the cell walls and if so what is their
fate?
The "activated" fatty acids (acyl-CoA) themselves
hardly leave the cell.
The fact that pH drops from ~5 to ~4 during
fementation is becuase of organic acids beeing thrown
out of the cell though. Excess acids in the cytosol
is stressful so the yeast should try to throw them
out to maintain cytosolic pH. Weak acids do more harm
inside the cell, than outside, since once inside
they protolyze completely and act as strong acids.
But to an extent they probably leak back in again.
Probably wasting lots of energy? But as it seems
most of these acids, except acetic acid
are probably TCA cycle intermediates?
I don't know what extent acyl-CoA can bleeds
off as acids? The only tioester hydrolases I've seen
in the genome database is a peroxisome enzyme that splits
the acyl-CoA into acid and CoASH. But it's reported
to be relate play a roll only in fatty acid oxidation?
Most organic acid analysis I've read about of beer
seems to indicate that the major acids found in the
beer are acetic acid + the TCA intermediates,
like citric acid, succinic, malic etc, but in some
analysis there also seem to exist a small amount of short
chain fatty acids, like propionic and byturic. But I
don't know if it's from yeast or bacteria.
It is an interesting question - what would happen
with the acetyl-CoA in yeast lacking of all alcohol
acetyltransferase genes? Would they be overly stressed and
drop significantly on high acyl-CoA pools and recover
more slowly from oscillations in growth conditions?
> 4. More practically--can I increase the iso-amyl acetate in my beer,
without increasing (and in fact reducing) isoamyl alcohol levels, by
simply adding acetic acid to the wort? I assume not, because how would
it get into the yeast cells and how would it get transformed to
Acetyl-CoA... but who knows?
>From what I understand acetic acid acids can get into the
cytosol from wort, and during *aerobic* conditions it
could even convert to acetyl-CoA. But that said, I think
that's not a way to increase the iso-amyl acetate anyway..
Maybe if we can fool the yeast to make the relevant
enzymes to a larger extent. What if we add a high dose of
iso-amyl alcohol or leucine in the starter? could that
increase expression of the banana enzyme? But how fast would
they deactivate once the need goes away?
Maybe ester synthesis beeing a regulation mechanism that
works "a bit wasteful" by bleeding off excess pools,
that complements the other existing regulation
mechanisms. Possibly useful for effiency in oscillating
conditions?
/Fredrik
------------------------------
End of HOMEBREW Digest #4846, 09/13/05
*************************************
-------
