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


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Contents:
  Straight-A [SEC=UNCLASSIFIED] ("Williams, Rowan")
  Re: Astringency (steve alexander)
  Re: Using a coolship to get enough HSA (bill keiser)
  Re: Priming sugar ("Joe Walts")


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Date: Fri, 19 Dec 2008 15:31:10 +1100
From: "Williams, Rowan" <Rowan.Williams at ag.gov.au>
Subject: Straight-A [SEC=UNCLASSIFIED]

Hi Rick,
Thanks for your enlightening post re Straight-A.  In Australia, we are still somewhat lacking in a diverse range of cleaners and sanitisers.
Do you sell your product here in Oz?  If not, you may want to give it some thought.  I like to use a different cleaner and sanitiser after each batch - I'm not chemist but I figure that if you keep changing the cleaner / sanitiser protocol, it denies the bugs an adaptive foothold...Logic or not, I haven't had an infection since 1995.

Unfortunately you can count the number of different sanitisers and cleaners I have on one hand, and that includes the container of Star San that I had shipped over from West Coast USA.

We'd welcome a new competitor to this market.

Cheers,

Rowan Williams
Canberra Brewers Club, Australia

[9588.6, 261.5] AR (statute miles)

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Date: Fri, 19 Dec 2008 02:36:47 -0500
From: steve alexander <steve-alexander at roadrunner.com>
Subject: Re: Astringency

Astringency is largely due to polymeric phenolic substances from grain
AND hops.  The simple monomeric phenolics are generally flavor
positive, or at least not negative.  As they grow in polymer size they
become more capable of binding with proteins and eventually when very
large they become less flavor active and also sediment more rapidly.
During the boil we lose most of the oxidized polymeric phenolics and
even some of the monomers in combination with protein as hot/cold
break.  Oxidation of unoxidized phenolics is the first step to
polymerization - OTOH oxidized simple phenolics are better than many
other oxidized compounds in terms of flavor.  [[monomeric phenolics
good, oxidized phenolics bad, polymeric phenolics very bad]]

This prescribes fresh ingredients and a good hard boil and avoiding
excessive oxidation as good practices.  Grind quality is noted as a
significant factor.  Much of grist phenolics are from the husk and
aleurone layer (between the germ and the endosperm) so shattering the
husks and over crushing the germ is bad.

Pat Casey and the long lost Spencer have commented to the main point;
a good tongue is the fundamental tool of a brewer.  You can learn with
a little experience when to stop sparging by taste.  It's subjective,
it's non-quantitative; it's also quite accurate.  You should taste
your late runnings as a QA technique even if you use other measures.

Nat H suggests
 > What seems to work good for me is setting the PH of the sparge
 > water to around 5.2 to 5.5.

It's well known that when using neutral sparge water the late runnings
have a rise in pH and at the same time phenolics and other less
desirable extract increases (as a percentage of extract) in the
runnings.  The pH rise is explained by the loss of organic acids in
malt.  The extraction of phenolics, cellulose and other less desirable
components is attributed to extensive malt cell membrane disruption.
There is NO EVIDENCE I've ever seen that keeping the sparge water
pH low prevents phenolic extraction.  This correlation of phenolic
extraction & pH rise at same time does NOT imply that this slightly
lower pH *causes* phenolic extraction.  It may, I can see some
hypothetical arguments to support the notion, but don't wager your
batch on this.  We should consider the idea that low pH sparge water
prevents phenolic extraction as questionable,
take-with-a-grain-of-salt.  Also very low or very high pH will cause
release of specific phenolic fractions.  You are probably safe (wrt to
phenolics) using any sparge water pH between mash pH (say 5.3) and the
natural pH of the grain (~7.5); lower is certainly not better.
Alkaline water will increase the wort pH and that's not good for break
formation or for fermentation.  *Do* remove carbonate buffering in
sparge water with acid, but the idea that lower pH prevents astringent
sparge is possibly just homebrew-voodoo, a sub-urban brewery legend.

If you discover astringency before the bottling/kegging then a dose of
PVPP(polyclar) can be extremely effective.  The same polyphenolics
that bond to protein at the back of your tongue will just as readily
bond to this plastic amide material and sediment out rapidly.  This is
a rescue effort and prevention is preferable.  It is however very
simple, effective and has little impact on beer quality otherwise.

PatC  says ....
 > and don't get greedy with your ingredients.

Yes !  Even at the high prices of malt these days, you'll find that
adding an extra pound of pale malt to the mash bill and then stopping
the sparge early can prevent astringency and also cause some
additional improvements to the beer flavor and aroma.  See if knocking
10% off your extraction efficiency doesn't help.

Another point is that channeling in the grist filterbed does cause
local overextraction and this may be a problem.  Your sparging
hardware matters.


Jason Gazely adds ...
 > I would like to elaborate on my process
 > a little in hopes that I may get even more helpful information. I use 
R.O.
 > water and build my mineral profil from scratch based on the color of my
 > mash. For this I use John Palmer's R.A. Spreadsheet. I add minerals to
 > both my mash and my sparge water.

Unless you add carbonates I seriously doubt an acid adjustment to
sparge water will help.  Won't hurt either, but don't expect much.

 > I have tried checking the gravity of
 > my final runnings using a refractometer but have found that to be
 > unreliable.

Please realize that a refractometer does NOT measure SG or brix; it
only measures optical rotation !  OR is a proxy for SG, SG is an
inverse proxy for phenolics.  Your tongue or an amide resin column is
the best tool for phenolic polymers.

 ...
 > Unfortunately this didn't work probably because most of my minerals
 > stayed behind in my HLT.

What does this mean ???  Problems dissolving the minerals ?  Calcium,
magnesium and carbonate ions have an impact on mash pH.  The rest can
go in the boiler.  Which are the problems ?

 > It seems like I have three options left.
 >
 > 1. go back to a less aggressive crush because I had no astringency 
problems
 >     then.

Crushed husk and crushed germ can certainly cause astringency. If
you feel you need a finer crush be prepared with PVPP post
fermentation.  There are other phenolic reduction methods but not
adaptable to HB.  OTOH I doubt that a good malt mill is causing this
problem.  So try increasing the malt and decreasing the extraction
efficiency (early sparge cutoff) and take a good look at your sparging
gear for channeling.  It's completely possible that  you are getting a
better crush so it requires less water to obtain the same extract.
Your increased efficiency implies this.

 > 2. Go to batch sparging and rely on the buffering power of the grains to
 >     maintain acceptable pH
 >
 > 3. Acidify my sparge water. But to what pH?

Batch may be gentler and prevent localized overextraction.  You could
try a pH around 5.5-6, but I doubt it will rescue an otherwise astringent
brewing method.

 -S




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Date: Fri, 19 Dec 2008 07:26:40 -0500
From: bill keiser <bk2 at sharpstick.org>
Subject: Re: Using a coolship to get enough HSA

<http://www.brew-dudes.com/hot-side-aeration/124>
  I'm fairly new to brewing and I confess, I didn't even know what HSA 
meant until I googled it, and found this article that explains the 
chemical reasons for it.
  In addition to this, from my slightly longer winemaking experience, I 
know that in the initial stages of fermentation, oxygen is good for the 
yeast, but as soon as it slows down, we use airlocks and CO2 to exclude 
too much oxygen from oxidizing it. After that, aging wine likes 
micro-oxygenation, typically/historically supplied through the pores of 
wood barrels. Now they can supply it withan aeration stone similar to 
those found in an aquarium. Some use a small airpump but pure oxygen is 
better. A cheap source for that is an old oxygen concentrator (aka 
oxygen generator) that separates the O2 from the N2. I got one for about 
$100 on ebay a while back to make my own oxygen bar,. (good for hangover 
treatment!)
bill keiser

> I just came across an abstract of a very old paper:
>
> Briant, L. "[Wort] Coolers - Use and Abuse of."
> J. Fed. Inst. Brewing, 1904, 10, 286-289.
>
> The paper is on open wort coolers (coolships) about
> which Briant surprisingly notes that "One of the most
> important objects of the cooler is to enable the wort
> to combine at high temperature (180-190F) with a
> suitable quantity of oxygen."
>
> Unfortunately in this abstract he doesn't explain why
> the HSA was desired.  Any ideas?
>
> Matt
>
>
>       
>   



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Date: Fri, 19 Dec 2008 08:04:22 -0600
From: "Joe Walts" <jwalts at gmail.com>
Subject: Re: Priming sugar

Hey Bill, great info!

I calculate my priming sugar based on the same molecular assumptions,
but I use the ideal gas law to convert the change in volumes of CO2 to
a change in CO2 mass and determine the priming sugar addition by
assuming the resulting CO2 is 48.9% of the fermentable sugar weight.
Bill's experiment resulted in a 90.6% solubility for corn sugar.
Using that number in my calculations results in larger amounts of
priming sugar than Bill's formula - about 20% for a target carbonation
of 2.5 volumes and a fermentation temperature of 68 degf.  Part of it
may be because I take into account bottle headspace and whether or not
they've been purged with CO2.  You can download my spreadsheet here
(it's the 'Carbonation Calculator' file):

http://jwalts.googlepages.com/math

Here are the priming sugar assumptions that I use, with a
newly-updated corn sugar solubility thanks to Bill's experiment:

Corn Sugar - 90.6% soluble, 100% fermentable
Cane Sugar - 99.7% soluble, 100% fermentable
Dried Malt Extract (Briess Pilsen Light) - 92.7% soluble, 80% fermentable
Liquid Malt Extract (Briess Pilsen Light) - 73.3% soluble, 80% fermentable

Fred: see if you can get in touch with Garrett Oliver.  He gave a nice
presentation on commercial-scale bottle conditioning at this year's
Craft Brewers Conference.

Joe


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