Monday, September 29, 2008

Homebrew Digest #5424 (September 29, 2008)

HOMEBREW Digest #5424 Mon 29 September 2008


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


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Contents:
Re: R.O. bewing / beers in Ulm (Kai Troester)
re: red lambda beer ("Chad Stevens")
Mash Temp and Color; Refractometer (Kevin Elsken)


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Date: Mon, 29 Sep 2008 09:58:50 -0400
From: Kai Troester <kai at braukaiser.com>
Subject: Re: R.O. bewing / beers in Ulm

> Most of the beers I have done since swiching to R.O water have been
> below 16 SRM. The last beer I did was an American Brown Ale at
> 20 SRM. I did notice a slight drop in pH but we are talking about the
> difference between maybe 5.3 down to 5.1. When should I worry? 5.0?
> 4.9? Or is 5.1 too low and 5.3 too high?

Jason,

The pH of a cooled (20-25C) mash sample should be between 5.3 and 5.5.
Being out of this range by 0.1 pH units won't hurt much but you will
start impeding the enzymes significantly once you get closer to or
below 5.0 or above 5.7. This can show itself as a longer
saccrification time, lowered extraction efficiency and/or less
fermentable wort.

Note that the actual mash pH is estimated to be about 0.35 pH values
lower at mash temps (65C) and 0.45 lower at mash-out temps (78C). But
that is somewhat moot as there are no practical ways (for the home
brewer) to measure the mash pH at mash temp. Both strips and meters
are designed to measure pH of a cooled sample. And the ATC feature of
a pH meter doesn't compensate for the pH shift of the mash. It only
compensates for the known temperature dependent change in the probe's
response. The actual temperature dependent pH shift of the substrate
also depends on the substrate thus the meter cannot account for that.


Kevin,

While not really beers from Ulm, here are some of my favorites when I
toured Bavaria this Summer:

Allgaeuer Brauhaus Teutsch Pils - An excellent southern German
interpretation of the Pilsner style. malty yet hop dominated with
great hop aroma and flavor (something that many brewers start to skimp
on). The lacing and head retention was just outstanding

Augustiner Edelstoff: - An excellent Export. malty and very drinkable


Kai

------------------------------

Date: Mon, 29 Sep 2008 13:47:42 -0700
From: "Chad Stevens" <zuvaruvi at cox.net>
Subject: re: red lambda beer

>So it turns out that to an astonishing degree of
accuracy one can determine the 1 cm absorption (-logarithm of the
transmission) spectrum of any beer (lambics, etc. excluded) from

>A(lambda) = SRM*[0.022798*exp( (430 - lambda)/17.268) + 0.97901*exp(
(430 - lambda)/81.87) ]/12.7

>where lambda is the wavelength (between 380 and 780 nm)....

A.J., yur killin' me! :o)

If (like me) you gave up when you ran into lambda and log functions...how
'bout this explanation..."Dude, if you want a red beer, start with about 1/2
of 1 percent roasted barley or black patent and work from there."

Chad Stevens
QUAFF
San Diego

(We still love you A.J....)

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Date: Mon, 29 Sep 2008 21:29:06 -0400
From: Kevin Elsken <littleboybrew at verizon.net>
Subject: Mash Temp and Color; Refractometer

I made two experimental 3 liter batches of about 10 deg P OE this
weekend. Both were
100 percent Maris Otter. I mashed one at 65 deg C (149 deg F) and the
second at
70 deg C (158 deg F). All other variables, as best I could control,
were kept the same.
(OEs were 10.4 and 10.6 deg P). Interestingly the wort from the low temp
mash was
noticeably darker than the high temp mash. I was not expecting the
difference, but
should I have? They are in 1 gallon jugs so the difference is unmistakable.

My second question is about my refractometer. It is the 0 to 30 Brix
ATC type that
seems quite common in most homebrew supply stores today. Promash
includes a
correction factor to allow to convert Brix to Plato. Promash indicates
it is typically
1.02 to 1.04 as I recall. I recently purchased two narrow range (by my
standards)
hydrometers. I can reasonably measure gravity to 0.01 +/- 0.005. After
carefully
measuring the gravity with the hydrometer (adjusting for temperature) and
comparing to my refractometer I see my refractometer measures in Plato
(i.e., my
correction factor is 1.0). Again, is this typical? I had calibrated it
at 0 deg Brix
(distilled water) but with regular wide range hydrometers I was always had
difficulty judging the gravity accurately.

Thanks for any insight.

Kevin Elsken
Little Boy Brewery
Upper Saint Clair, Pa

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End of HOMEBREW Digest #5424, 09/29/08
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