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HOMEBREW Digest #4908
HOMEBREW Digest #4908 Fri 09 December 2005
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Fermentation tracking ("Fredrik")
$600 Tables etc. ("A.J deLange")
RE: Cake-taking record anal CO2 tracking (Jeffrey Byers)
CO2 flow meter (ALAN K MEEKER)
re:decoction vs infusion (Nathaniel Lansing)
RE: A couple of questions/remarks regarding #4905 & #4906 ("Mike Sharp")
-S (zuvaruvi)
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Date: Fri, 9 Dec 2005 08:08:33 +0100
From: "Fredrik" <carlsbergerensis at hotmail.com>
Subject: Fermentation tracking
The measurement discussion is reaching an end now and Ken
posted some of his nice flow meter data. I'll just add again my
support for the gas flow measurement ideas that has been discussed
before and I haven't changed my mind, because I've already
learnt things from it, so it works for me, growing confidence
intervals aside.
My opinion is that while we should *of course* always strive
to improve accuracy and certainty in measurements, we must
not be fooled and rejected by noise! Sometimes what we
blaim on "noise" is nothing but a mirror of our own ignorance.
I always try hard to never confuse unlikely or diffucult, with
impossible, because they are fundamentally different. Once
you *think* something is impossible, when it might just be darn
tricky, you aren't even trying! and your world is instantly smaller.
Just look at life, it's amazing. But is it probable? What do I know.
I do not have as nice flow meter as Ken, but I've toyed around
with counting bubbles, and even such admittedly less accurate
method is very useful. But you need averages, not single counts
of course. Also you kow the end points anyway, since I typically
measure OG and FG anyway as a doublecheck. That's good enough
for a starter. I had my computer count the bubbles for me. I made two
working prototypes, one trigging on the sound(microphone in airlock),
one using a optical fotosensor & emitter in airlock neck. But since
then I haven't worked more on it. I've acquired the first basic
info I needed for a test. The next task in order to make sense out of the
profile is the modelling, that's where I am atm. Once that's done
I'll probably revise the measurement process.
The fermentation profile contains alot of information about
yeast growth and the nutritional status of the wort, which
in turn may have significant impact on flavour formation.
You don't get near these things from single OG, FG readings
except if you note the total fermentation time. But the information
doesn't present itself in english letters, you have to *pull* it out
yourself by means of your imagination/creation.
I have also done some pre-tests with measuring the heat of the
culture, using one probe in the fermenting culture and one outside.
The Differential temperatur again nicely mapped out the typical activity
profile (acceleration, peak, deacceleration) as is expected by theory.
I used cheap temperature transducers wich are not overly accurate, but
they are fairly precise. Add on top of that, that noise reduction, and
calibration if you want, and you can get pretty good numbers, for little
money.
Sure you can go an buy PRO gear which are great and easy to use,
but it easily gets out of budget for a homebrewer. Does that mean we
are stuck? I don't think so, only if we think so. Our imagination and
creativity is the biggest bottleneck. Consider how this world started, we
should not fear noise and darkness :)
I think that we sould not be blinded by incompleteness and noise, my
strategy is to compare all the data I get possibly get, with theory. In this
way I trust theory to also help me tell what's significant and what's not.
I believe in a certain degree of self rectification as inconsistencies are
short lived. To a certain extent this happens also in the observers mind,
not only in the measurement instrument.
I think the gas analysis (by various means), temperature analysis, and
maybe head pressure analysis are all methods well wort exploring. And
it doesn't *have to* take a million dollars of lab equipment. Of course it
would make like easier, but that's another story. We have to play the cards
give to us.
/Fredrik
------------------------------
Date: Fri, 09 Dec 2005 13:13:51 +0000
From: "A.J deLange" <ajdel at cox.net>
Subject: $600 Tables etc.
$600 Tables: The ASBC is the American Society of Brewing Chemists. It
is, among other things, the publisher of a set of "Methods of Analysis",
a set of protocols for measuring properties of malt, wort, beer, hops
adjuncts etc. The MOAs come in a hefty three ring binder or on a CD and
the cost is nearly, if not quite, $600. Several of the methods contain
or refer to tabulated data which is found in the Appendices. An example
is the set of hydrometer corrections Steve and I have been referring to.
Others are strengths (Plato) of wort at various specific gravities
(Plato tables), specific gravities of alcohol solutions and the
statistical tables necessary to carry out the triangle test Steve
referred to in his post today. A subset of the MOAs i.e. those which are
most likely to be used by craft brewers is also available for
substantially less than $600.
My comment "save your $600" referred to the fact that much of the
tabular data is easily expressed in terms of a polynomial. Strength of
wort, for example, can be calculated from specific gravity by P =
(((136.10405*S - 630.60634)*S + 1111.48785)*S - 616.98918 where S is
specific gravity. Note that this is not the "official" ASBC polynomial
but the result of my own fit to the data which I am posting here out of
respect for the copyright laws and because it is a better fit (though
not to the extent that it makes any real difference). I also have
polynomials for alcohol solutions and water and little Excel spread
sheet that calculates the triangle test probabilities. I posted
polynomials for the hydrometer corrections the other day. Anyone who
wants any of this stuff should just drop me an e-mail.
Decoction: I think the beers I decoct are delicious. If that is because
of something other than decoction please don't shatter my fantasy that
it is.
GAC: Stands for Granulated Activated Carbon. Wonderful stuff in that it
has a huge effective surface area per unit weight and the activated
sites will adsorb and/or react with a wide assortment of things like
chlorine and chloramine in brewing and Sarin and Tabun in a soldier's
gas mask and chemical suit.
Density: The formal definition is the mass per unit volume so if
whatever you are interested in is contained in the volume you define it
will effect the density. Fish in a swimming pool will effect the density
of the water in the pool if the volume contains the entire pool. They
will not if the volume is defined as a 1 cc sample drawn from the
surface. Whether or not something in suspension is detected by a
measurement depends on the measurement technique. A hydrometer reading
depends on whether the hydrometer displaces the suspended objects which
clearly isn't the case with fish or tires thrown into the pool (besides
which the fish adjusts his swim bladder to maintain neutral boyancy so
his density is that of water) but it would displace yeast cells. In an
oscillating U-tube meter or pycnometer what gets measured is the total
mass in the sample tube (which is of fixed volume). If fish or tires got
in there they would influence the reading (except for the fact that the
fish is of neutral buoyancy).
CO2 Tracking: That's pretty cool.
------------------------------
Date: Fri, 09 Dec 2005 07:39:20 -0600
From: Jeffrey Byers <jbyers at yakfarm.net>
Subject: RE: Cake-taking record anal CO2 tracking
Very cool.
two questions.
Do you monitor the CO2 outgas rate periodically and assume rate is
linear between measurements to perform the total CO2 calculation or do
you monitor continuously?
Is the output from the flow meter electronic or mechanical?
I am thinking of using a PIC microcontroller (cheap under $10) to do the
same thing and send the information (flow rate vs time) directly to my
computer. Need to buy or build (and calibrate) a meter the PIC can read.
regards,
jefe
------------------------------
Date: Fri, 09 Dec 2005 08:45:04 -0500
From: ALAN K MEEKER <ameeker at mail.jhmi.edu>
Subject: CO2 flow meter
Ken Anderson gave a link to data from his CO2 flow meter,
Nice graph! Would like to see the SG plot expanded.
Was this the calculated SG form the CO2 measurement or
was the SG independently measured? How much was the
meter? Based on your numbers it looks like your fermentation
gave off about 5.5 pounds of CO2 which sounds about right
for a 10+ gallon batch and considering that only about 1/3
of the sugar mass could get converted to CO2.
==========================================
Alan Meeker, PhD
Assistant Professor of Pathology
Department of Pathology
Division of Genitourinary Pathology
Bunting-Blaustein Cancer Research Building Room 153
1650 Orleans Street
Baltimore, MD 21231-1000
------------------------------
Date: Fri, 9 Dec 2005 09:37:26 -0500
From: Nathaniel Lansing <delbrew at compuserve.com>
Subject: re:decoction vs infusion
In the BT article decoction vs infusion there were some problems
with attenuations and lag times. I'd hardly draw on that experiment
with disorderly fermentations as the definitive answer.
Perhaps the yeast selection is the determining factor that accentuates
the maltiness precursors formed in the decoction mash. If I remember
correctly the yeast used was 2206, not a particularly malty yeast to
start with. With orderly fermentations another yeast could very well
have indicated the differences.
That experiment had as many error factors as a hydrometer, and I doubt
it could be repeated; my hydrometer at least has some repeatablity.
>From JIB vol 108:1 (2002)"Although not investigated in the current work
different
yeast strains produce different amounts of furanones from
the same worts2,13. Therefore it would seem feasible that
suitable choice of yeast strain could be used to increase or
decrease beer furanones from the same worts."
------------------------------
Date: Fri, 9 Dec 2005 10:19:49 -0800
From: "Mike Sharp" <rdcpro at hotmail.com>
Subject: RE: A couple of questions/remarks regarding #4905 & #4906
Bill Velek asks: What is "GAC filtration"? I'm guessing that it might be
Ground Activated Carbon or something like that.
Close. It's Granular Activated Carbon. Most home filter are composed of
small grains of activated carbon. loosely packed. IMO, the finer the grain,
the better. As someone pointed out, a monolithic block is best, but you
don't see those very often, and they require higher pressure. In fact, I'm
not completely certain I've ever seen it used for water filtration, though
it's fairly common for air filtration. I believe monolithic AC filters do
support a higher flow rate than a granular bed of AC. This isn't because
the carbon is better, but it's due to the kinetics of the flow of the fluid,
and the fact that the effective surface area is much higher (which seems
counter-intuitive).
As an interesting side point, the activated carbon that is used to fill the
vacuum space of a thermos flask (dewar) is actually made from coconut
shells. These produce an extremely high quality form of AC (very small
pores) which is better at adsorbing hydrogen. Hydrogen is generally the gas
that leaks in and ruins your vacuum bottle. Activated carbon, when it's
used to adsorb gas like this, is called a "getter".
Regards,
Mike Sharp
Kent, WA
[1891.3, 294deg] AR
------------------------------
Date: Fri, 9 Dec 2005 13:23:56 -0500
From: <zuvaruvi at cox.net>
Subject: -S
>Steve Alexander, thanks for setting me straight on >specific gravity and
>buoyancy; your explanation regarding the fish rising when >a boat is
>launched makes perfect sense to me. That's what I love >about this hobby
>and this group: I'm always learning stuff. As for your >comment about
>monitoring gravity during the fermentation, whatever >floats your boat;
>but....
Don't encourage him, he's already got a fat enough head....
XXOO,
Chad
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End of HOMEBREW Digest #4908, 12/09/05
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