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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
		Digest Janitor: pbabcock at hbd.org


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Contents:
  re: decoction ("steve.alexander")
  A couple of questions/remarks regarding #4905 & #4906 (Bill Velek)
  sour ale how to (Ken Pendergrass)
  Cake-taking record anal CO2 tracking (Ken Anderson)


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Date: Thu, 08 Dec 2005 01:53:42 -0500
From: "steve.alexander" <-s at adelphia.net>
Subject: re: decoction

Mark Prior writes a very interesting report
on decoction vs RIMS results.  Of course others, from ???
at UC Davis to Louis Bonham in a BT article have found
there is little or no perceptible flavor advantage to
decoction.

My personal *belief* is irrelevant, but for disclosure,
I think there is a small advantage - but smaller than most
advocates imply.

If Mark wanted to take his conclusion:
"[...] it does produce a perceivable flavor difference in
my  opinion",  from the realm of mere subjective opinion to
the form of an objectively measurable result with
statistical measurable significance, it's not very hard
and doesn't require a gas chromatograph.
 
It's called a triangle test and all that is needed
is set of opinionated beer drinking friends and 3
times as many sample cups.

Each tester is given three beers, two from one batch
and one from the other.  The tester is given no indication
of which is which; however the experimenter must keep track
of this by means of labellings the cups in some non-indicating
manner.  Also the method of labeling should prevent two
testers from comparing their results.  It's unlikely you'll
be able to prevent all subliminal or even overt communication
between beer drinking testers, so someone holding up a cup
labeled "3" and announcing it's the good one should not bias
the result.   It's better to just label the cups from 1...3N
and then on a hidden paper make a pseudo-random assignment of
beers to cups to that each tester gets two of one and one of
the other.  Of course roughly as many testers should get two
RIMS samples and one Decoct as the other way around.

The testers are asked to fill out a questionnaire beginning
with:

0/ List the labels of the three samples: __ __ __

1/ Which of the beers is different from the other two ?

Followed by any number of comparative difference questions
2/ Which do you prefer (if any) ?
3/ Can you describe the difference ?
4/ Which is maltier tasting (if any) ?
5/ Which has better aroma (if any) ?
 ...

Question 2/ (preference) is a pretty basic question which
should usually be included.  3/ is an open ended question
which is not likely to give any statistically useful result,
unlike 4/ and 5/ which ask for a comparative difference.


In analysing the results you first have to determine how
many people were able to correctly identify the "different"
beer by looking up their beers they sampled from Q.0 on the
hidden sheet and comparing this with their answer to Q.1 .

To get statistical significance that the beers are
distinguishable at the 1% level (which is really quite
good) you need to have 5 or 6 testers who ALL correctly
ID the different beer.  6 out of 7 will do as well.
7 of 8 or 7 of 9 correct IDs work, as well as 8 correct
of 10 or 11. 

The sweet part about this blind 3-way selection is that
since each taster only has a 33% change of randomly
IDing the different beer, you really don't need many
testers to obtain a significant result for difference.
Chance is against it.

The Chi square stats work a little differently on the
preference/comparison type questions where only the
"correct ID"  questionnaires count. [[This deserves a
separate discussion.]]

fwiw,
 -S




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Date: Thu, 08 Dec 2005 02:42:42 -0600
From: Bill Velek <billvelek at alltel.net>
Subject: A couple of questions/remarks regarding #4905 & #4906 

What is an ASBC correction table?  If it is just tabulated data, why 
$600.00?

- ---
Michael, regarding your "All Things Beer Map", you might want to add a 
microbrewery in Little Rock, Arkansas, called "Diamond Bear Brewery".  I 
have no connection with it whatsoever, but they make very good beer and 
they give a nice tour with generous free samples of their brews.  Here's 
a link: http://www.diamondbear.com

- ---
What is "GAC filtration"?  I'm guessing that it might be Ground 
Activated Carbon or something like that.

- ---
If one lets the cold break settle out before pitching their yeast, would 
there be any advantage to racking the beer off of it to first, 
especially if one plans to reuse the yeast cake on the next batch?  Or 
is the cold break beneficial for the yeast?  I seem to recall that it 
might be used for sterol production or something like that.

- ---
Dave, regarding Clinitest, am curious whether your comment was meant to 
mean that any sugar testing method would work, as opposed to 
specifically just Clinitest.  I'd think that any urine testing tapes, 
and maybe even the blood sampling devices for diabetics might work, 
wouldn't they.

- ---
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 please don't think for a moment that I differ much from your notion
"that knowledge itself is a good, and more is universally better than 
less."  I fully agree with that ... but would certainly limit it to 
things that matter (like the heart patient, or being able to take some 
sort of corrective action to fix your beer).  If you can find a way to 
_USE_ the data you collect, then that's great; otherwise, more knowledge 
- -- like knowing how many steps an ant takes in mile -- is worthless.

Cheers.

http://tinyurl.com/7zpob is my 'Brewing Glossary' with photos and links! 
http://tinyurl.com/99s2l compares HomeBrewers Team stats w/ other teams. 
http://tinyurl.com/axuol moderated group (now 304 member) EXCLUSIVELY re 
equipment for craftbrewers and small breweries. Please visit. Bill Velek



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Date: Thu, 08 Dec 2005 11:38:42 -0500
From: Ken Pendergrass <kenp794 at comcast.net>
Subject: sour ale how to

I'm interested in brewing sour ales both the Belgian and antique 
versions of other styles which were sour because all beer at the time 
was fermented in wood. If you brew in this style how do you do it? I 
confess I'm just starting the process of rereading all the materials I 
have on the subject. That having been said it seems to me the best way 
to do it would be to make a "stock", if I'm not using the wrong term, 
ale aged till it's quite sour which is used to blend with "fresh" ale do 
you agree? What about wood? I'm thinking of just wedging in a small 
board. Open or closed fermenter?
Thank you,
Ken
in Ypsilanti




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Date: Thu, 08 Dec 2005 12:28:41 -0500
From: Ken Anderson <kapna at adelphia.net>
Subject: Cake-taking record anal CO2 tracking

I might have to take the prize here.  I use an inexpensive (eBay) mass 
flow meter, and I love the thing.  It gives me a constant snapshot of 
the fermentation's progress.  The SG gets calculated from the the CO2 
gas produced, which is tied to the sugar depletion.  Some experienced 
brewers like to discredit the usefulness of airlock activity.  That may 
be true if you're just counting bubbles, but if the gas output is being 
carefully monitored, it's VERY useful.
Here's one of the resulting graphs, as an example:
http://users.adelphia.net/~aken75/
Ken Anderson



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