---

	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
		Digest Janitor: janitor@hbd.org


***************************************************************
       THIS YEAR'S HOME BREW DIGEST BROUGHT TO YOU BY: 

                  Beer, Beer, and More Beer
      Visit http://morebeer.com to show your appreciation!

    Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********


Contents:
  WLP002 ("Gordon Strong")
  Re: Post your location (Mike S)
  Re: Cheap Refrigerator Temperature Controller (Michael Hartsock)
  Re: fermenting in corny question (Jeff Renner)
  RE: Carboy blowoff tube (Bob Hall)
  Enzyme Liquification process vs Starch liquification ("Fredrik")
  Re: fermenting in corny question ("Michael O'Donnell")
  Re: WLP002 (re: Curious Yeast Behaviour) ("Richard S. Sloan")
  Re: Britsh Homebrewing, Homebrewed Temperature controllers ("Greg 'groggy' Lehey")
  Magnum hops ("William Frazier")
  HopTech hop oils ("Peter A. Ensminger")
  Fix and the 40C Rest (Stuart Lay)
  Electric Blankets ("Nathan T. Hoskins")
  RE: Orlando Brewpubs ("Steve Jones")
  1/6 bbl Sankeys (Marc Sedam)
  Re: Enzyme Liquification process vs Starch liquification ("-S")
  Link of the week - gotmead (bob.devine)


* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*           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.

JANITOR on duty: Pat Babcock and Spencer Thomas (janitor@hbd.org)



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


Date: Thu, 8 Apr 2004 23:23:56 -0400
From: "Gordon Strong" <strongg at voyager.net>
Subject: WLP002

Responding to #4516 where WLP002 was compared with WY1275...

They shouldn't have the same characteristics because they're different
yeasts.  WLP002 = WY1968 = Fuller's.  No doubt about it.

It's my favorite English ale yeast, and is great for cask ales.  It flocs
like nobody's business.  I hauled a pin of my ESB to the Real Ale Festival
two years ago (6 hour drive in the back of a van in the snow), dropped it
off in the afternoon, and the next morning the first pint pulled bright.
Now *that's* a flocculant yeast.

Tip: don't let it get below 65F while fermenting because it will drop on you
like a rock, regardless of how much sugar is still present.  I think 68-70F
is the sweet spot for this yeast, flavor profile-wise.  I've used it in
ESBs, milds, porters, old ales and some American styles (like APA) when I
was too lazy to start a different yeast and was able to repitch.

Gordon Strong
Beavercreek, Ohio



Return to table of contents


Date: Fri, 09 Apr 2004 07:08:34 -0400
From: hbd at flatsurface.com (Mike S)
Subject: Re: Post your location

At 10:12 PM 4/6/2004, Request Address Only - No Articles wrote...
>It's time for my semi-annual request that posters tell us their name 
>and location.  It fosters community and might help answer questions.

Mike Sauve, Lurker
[10.4, 9.8] Apparent Rennerian 



Return to table of contents


Date: Fri, 9 Apr 2004 05:40:20 -0700 (PDT)
From: Michael Hartsock <xd_haze at yahoo.com>
Subject: Re: Cheap Refrigerator Temperature Controller

I dealt with this problem not too long ago.  I DO not
recommend using the temperature genie.  I built this
controller:

http://hbd.org/mtippin/tempcont.html

It is based on a radioshack module that must be
special ordered over the phone.  It was 19.95 with
5.00 shipping.  I'm not sure that this module is
cheaper than a store bought controller once all the
other pieces are purchased.  But, unlike the cheap
mechanical ones, I can set any temperature and any
differential.  Also, I can switch it to heat and use
it to operate a heating element (power resistor or
lamp).  

It is probably cheaper to build than to buy one with
similiar features.  But if you don't have much
experience with ciruit building, this probably isn't
the place to start.  But if you're like me I like to
brew my own, and I feel the same way with electronics.

Mike,
Columbia, MO

=====
"May those who love us, love us.
And those that don't love us,
May God turn their hearts.
And if he doesn't turn their hearts,
may he turn their ankles
So we'll know them
by their limping."



Return to table of contents


Date: Fri, 9 Apr 2004 09:20:59 -0400
From: Jeff Renner <jeffrenner at comcast.net>
Subject: Re: fermenting in corny question

Pat Reddy <RiverBound at charter.net>, who heeded half my semi-annual 
request and included his name when he posted, but neglected to 
include where he is, writes:

>I am considering conducting my primary ferm in glass and my secondary in a
>corny keg.
>1) What do I use to plug the inlet and outlet of the keg with?  I assume
>there is some kind of fitting that will screw on to the posts of my ball
>lock kegs.

I don't use kegs for actively fermenting beer.  I transfer the beer 
to them when  it's about done fermenting and allow the last bit of 
fermentation to carbonate the beer.  Sometimes I have to adjust this 
by venting or adding CO2, but surprisingly often it's OK.

However, if you want to release the pressure, I'd suggest using the 
regular fitting on the beer-out side.  For the gas-out side, get a 
small bored rubber stopper that fits and but a bubbler in it.  Or, 
you could screw on the ball-lock post and put a gas-out fitting on 
it, then put a hose on it and run it to a bottle of water so you will 
have a bubbler.

>2) Is there an easy way to attach a blow off tube to my glass carboy?

There are two ways, and one is much safer.  The old, less safe way is 
to use a #7 or so bored rubber stopper and insert a short section 
(2") of old racking cane, then attach a hose to this and run it into 
a bottle or jug or bucket of water.

The problem with this is that it can clog with hop particles or yeast 
and, if you are lucky, blow the stopper out of the carboy, resulting 
in beer all over the ceiling and room.  If you are unlucky and the 
sticky wort/beer has stuck the stopper in the neck, you will get an 
exploding carboy.

The safer method is to use a 1" diameter plastic hose.  It will jam 
tightly in the neck of the carboy, and you can stick the other end in 
a bucket of water (with or without sanitizer in it).

I have three 24" or so lengths of 1" hose and use them to clean up or 
to fill carboys by shoving the end over the faucet in my laundry tub. 
Not as neat as using a threaded fitting, but quick and easy.

Jeff
- -- 
Jeff Renner in Ann Arbor, Michigan USA, JeffRenner at comcast.net
"One never knows, do one?"  Fats Waller, American Musician, 1904-1943


Return to table of contents


Date: Fri, 09 Apr 2004 09:25:23 -0400
From: Bob Hall <rallenhall at henry-net.com>
Subject: RE: Carboy blowoff tube

Pat Reddy asked about carboy blowoff tubes. I found that 1.25" OD vinyl 
tubing fits snuggly into the neck of my glass carboys. It's about 1" ID, so 
will not clog with chunks of yeast and debris, and is large enough to be 
cleaned with a bottle brush.

Bob Hall,
Napoleon, OH
[51.2, 197.8] Apparent Rennerian


"I am Robert A. Hall, and I have approved this message." 




Return to table of contents


Date: Fri, 9 Apr 2004 17:00:46 +0200
From: "Fredrik" <carlsbergerensis at hotmail.com>
Subject: Enzyme Liquification process vs Starch liquification

Hello everyone,

I am making some slow progress on the computer simulation of the mash but I
miss some information. I hoping some of you guys has some input. Steve?

I have now arrived at a simplified liquification model for the starch, which
is the first step in the mashing process. The enzyme process is almost
figured out. I hope to model the carbohydrate distribution, % vs polymer
size with time. From this one could calculate fermentability and maltotriose
contents, which I consider the most important paramters. If this works as I
think I'm going to implement a very similar model for the protein regime, to
model protein distribution with time.

The question how the liquification of the enzymes compare to that of starch?
For starch I assume an intermediate gel stage, and from gel to liquid there
is diffusion that is also promoted by stirring. I am assuming the enzymed
are liquified faster than the starch, but somehow I need to quantify this. I
hoping someone has some info on this?

So far I am assuming the amylose and the amylopectin are liquified at the
same speed. Would there be a problem with this assumption?

Here are some fun graphs so far. Lots more to come later.

http://hem.bredband.net/frerad/beer/mashsim.jpg

The activity graph for beta and alpha doesn't have the same scale, but it
accounts for both the liquification and denaturation. During the enzymatic
breakdown of the starch these activity curves will govern for the total
enzyme concentration with time.

Note: the model isn't yet parametrized corrently. I have just thrown in as I
think "sensible" values that comply with the data I have seen so far.

If anyone has some info on the rate of liquification of alpha and beta
amylase I would be very interested. I figure I also need to account for the
glucanase rest. I will do that very crude, and just assume that the glucans
suppress the rate of diffusion from the gel? I haven't found any info on
this either?

 /Fredrik


Return to table of contents


Date: Fri, 09 Apr 2004 08:28:22 -0700
From: "Michael O'Donnell" <mooseo at stanford.edu>
Subject: Re: fermenting in corny question


>Pat Asks about fermenting in corny's...  I switched to them for all 
>fermentation a while ago and have been really happy.

>I am considering conducting my primary ferm in glass and my secondary in a
>corny keg.

Let me just put in a plug for using them for primary is well... they sure 
are easy to clean compared to glass (because my arm fits all the way 
in).  On the downside, you don't get the yeast show.


>I have 2 questions...
>1) What do I use to plug the inlet and outlet of the keg with?  I assume
>there is some kind of fitting that will screw on to the posts of my ball
>lock kegs.

I tried for a while to jam a hose into the overpressure hole, but couldn't 
get it to seal.  I made up a special barbed fitting to go into the 
overpressure hole, but abandoned it in favor of some advice from this 
group:  take the gas-in post off, remove the poppet and screw it back on... 
actually, take it to the hardware store first, because I don't remember the 
size, but one size of vinyl tubing fits over it quite snugly (Maybe 
5/8"i.d., but check)... shove this over the post and you have blowoff 
tube.  When the time comes to rack, or just take a sample, pull the tube 
off, replace the poppet, add some gas and push away.

Some people advocate cutting the bottom of the dip tube off... I did this 
on 2 of my kegs, but am not sure if I would again... instead, I'd probably 
just bend them at a slightly tighter angle so they sit farther from the 
bottom.

Also, I have had trouble getting the lid to seal properly.  The problem was 
that I chose 2 of my more-beat-up kegs to use as fermenters and the rims 
were dinged.  I switched to a better set of kegs and have had no 
problems.  Some people suggested using the slightly thicker o-rings from 
Williams Brewing, and that is what I would have tried next if the new kegs 
didn't work.

cheers,
mike
Monterey, CA



Return to table of contents


Date: Fri, 9 Apr 2004 08:57:46 -0700
From: "Richard S. Sloan" <rssloan at household.com>
Subject: Re: WLP002 (re: Curious Yeast Behaviour)

> Has anyone used this strain before?  How did you like it?  I
> understand that it is perhaps the Fuller's ESB Strain?  Should be
> good.  Looking forward to it.

I use WLP002 in my Mild w/Rye and like the results. I dont percieve a lot
of fruitiness in the finished product. I like it for its high flocculation.
I can bottle/keg after 7-8 days in primary and have clear beer. No need for
a secondary as the yeast packs well. As long as I build a starter and
aerate my wort I get a good attenuation. My Mild goes from 1.038 to 1.009
(approx 76%).

Richard Sloan
San Diego, California




Return to table of contents


Date: Sat, 10 Apr 2004 10:18:07 +0930
From: "Greg 'groggy' Lehey" <grog at lemis.com>
Subject: Re: Britsh Homebrewing, Homebrewed Temperature controllers

On Thursday,  8 April 2004 at 13:01:26 -0400, Dave Burley wrote:
> Brewsters:
>
> Ken Scammell laments: "I sure wish homebrewing was big over here" in Britain.
>
> When I lived in Britain in the late 60s ( so I am undoubtedly a little out of
> date, although I visit Britain routinely and my daughter lives in London)
> Homebrewing was bigger - and more importantly - legal ( which it wasn't in the
> US at the time).
>
> A simple trip into Boots the Chemist ( a drug chainstore)  was a wonderous
> event for me the first time. Imagine malt extract, hops and YEAST! on the
> shelf and BOOKS!  I had never imagined it.
>
> Before moving to Britain for Post-doctoral studies, I had been struggling in
> the US using Blue Ribbon malt extract, 1930s Prohibition information and yeast
> of unknown pedigree - the only hops were those in the extract.
>
> I have to say I never tasted any good homebrew other than mine ( and my
> labmate's who I taught)  while I was in Britain. I am sure that is no longer
> true, but then the practitioners of homebrewing were not intellectuals and the
> focus ( as you will see in the early books)  in cradle-to-grave Socialist,
> Pre- Maggie Thatcher and North Sea oil Britain was to cut costs - not make
> better beer . Homebrew in Britain suffers from ( at least then) a well
> deserved bad reputation.

This tallies pretty well with my own experience at the time.

> I think there were several origins for this. The first, Boots with
> nationwide distribution sold the products with a normal markup and
> prevented specialty stores from getting into the business.

I'm not sure that that's the case.  I brewed quite a bit during my
university days in the 1970-1972 time frame, and I bought most of my
supplies from specialty places, including some people at the local
(Exeter) market.  I wasn't very impressed by what Boots had to sell.

> The early homebrew books were of pretty poor quality ( J.J. Berry a
> publisher and author, writing books to publish, springs to mind).

Indeed.  When I got back into brewing last year, I dragged out a
couple of his books.  The recipes are horrendous.  I also have a
couple of books by Ken Shales, with the promising sounding titles
"Brewing Better Beers" and "Advanced Home Brewing".  Despite the
title, all recipes in the latter book seem to base on DMS (diastatic
malt syrup).

> Also, after the second world war, the brewing industry in the US had
> become monolithic and devoted to the accountants and making ever
> more uniformly tasteless, colorless beers. Britain, of course, at
> the time had an incredible variety of beers which varied from region
> to region.

Hmm.  I can't confirm that in the early 70s.  One of the reasons I
made my own beer was because I didn't like what I could buy.  The beer
from the local brewery (Devenish) was undrinkable.

Greg
- --
Note: I discard all HTML mail unseen.
Finger grog at lemis.com for PGP public key.
See complete headers for address and phone numbers.


Return to table of contents


Date: Fri, 9 Apr 2004 23:30:46 -0500
From: "William Frazier" <billfrazier at worldnet.att.net>
Subject: Magnum hops

Pony Express brewery makes Rattlesnake pale ale.  It's a good beer with a
strong bitterness.  The information given on their website says Magnum hops
are used for bittering.  My son-in-law drinks this by the case so I want to
brew something like this beer.  I've been having a debate with a beer making
friend about how many ounces of Magnum to use in a strongly bitter ale.  I
have no experience with the hop.  For those who have used Magnum what would
you suggest.  TIA.

Bill Frazier
Olathe, Kansas USA




Return to table of contents


Date: Sat, 10 Apr 2004 01:25:43 -0400
From: "Peter A. Ensminger" <ensmingr at twcny.rr.com>
Subject: HopTech hop oils

Just ordered some hop oils from HopTech: 2 oz of "British Blend" and 2 
oz of "East Kent Goldings". As soon as they arrived, I took whiff. The 
British Blend was unimpressive/anemic. The EKG was definitely EKG, but 
not as strong as expected.

A Google search for "site:hbd.org hoptech oil" was not very informative. 
Excluding posts from Mark Garetz (who sells the stuff), Al K, CD 
Pritchard, & S. Wesley suggested using 2-3-fold more than suggested by 
HopTech. My impression is that I could never use these products to 
achieve the hop aroma of a Victory Hop Devil, 
http://www.victorybeer.com/hopdevil.htm (which uses American hops BTW). 
Any other HBDr's use these HopTech products? Your thoughts?

Cheerio!
Peter A. Ensminger
Syracuse, NY
http://hbd.org/ensmingr




Return to table of contents


Date: Sat, 10 Apr 2004 06:32:31 -0500
From: Stuart Lay <zzlay at yahoo.com>
Subject: Fix and the 40C Rest

In a post in HBD 4515 discussing head retention, Jeff Renner talked a 
little about a George Fix mash schedule that used a rest at 40C:

"I suggest eliminating any rest below ~144F.  The old "acid rest" or
hydrolysis rest of ~100F is just not necessary for modern malts (nor
is the protein rest).  It doesn't hurt, it's just a problem getting
from there to the sacch. rest."

A couple of questions...Fix indicated his research showed that yields 
were improved by having a rest at 104 when compared with a single rest 
at ~ 150 degrees.  Does your experience differ?  Have malts changed 
that much in the ten years or so since he wrote this book?

Did Fix modify his opinion concerning the utility of this rest after he 
published An Analysis of Brewing Techniques?

I agree that resting first at 104, then infusing to 140 then 158 leads 
to a very dilute mash.  In at least one BYO article, John Palmer has 
described a mash with 2 quarts liquid/pound of grain to be a normal 
mash.  What's a normal mash for you?  Are there advantages to a stiffer 
mash?

I ask because I would like to use a 40/60/70 schedule, but since my tun 
is a converted cooler, I think the mash will be too dilute.  I've 
adopted a modified schedule of a 104F rest for thirty minutes followed 
by at least 60 minutes at 150.  I'm pleased with the beers I've made 
this way, but really don't have all that much experience by which to 
judge,

After settling at 150, my mash ends up diluted to about 1lb/2 quarts.  
I've read a number of posts from folks who use RIMS/HERMS that use 
about 1lb/1.25 quarts.   Do I have room for improvement here?

Thanks,

stuart
San Angelo, West-by-God Texas



Return to table of contents


Date: Sat, 10 Apr 2004 08:23:10 -0400
From: "Nathan T. Hoskins" <nathanhoskins at adelphia.net>
Subject: Electric Blankets

Ok, I've got a question.  I was looking at a recipe for a Belgian Strong
Ale, and it called to, "heat fermenter with electric blanket to 90-100
degree for 12 hours after fermentation begins."  Wouldn't that destroy
the yeast?  Is this an unusual process?

Nathan T. Hoskins
Brewing in Kentucky
nathanhoskins at adelphia.net

 

- ---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.654 / Virus Database: 419 - Release Date: 4/6/2004
 



Return to table of contents


Date: Sat, 10 Apr 2004 11:25:33 -0400
From: "Steve Jones" <stjones1 at chartertn.net>
Subject: RE: Orlando Brewpubs

Thanks to all who responded. Though my post didn't go in
until Monday I did have access to email and got your
reponses. There were a few suggestions for good beer bars,
but alas - no brewpubs.

However, before leaving I went to the CFHB website and
discovered that they were meeting on Sunday, the day I would
arrive. Though I was a bit late, I went to their meeting and
got a wealth of infomation on places to try, not to mention
some great homebrew. As all homebrewers know, the club
offered great hospitality to a fellow homebrewer, so my trip
was as good as it could be.

Thanks to CFHB, and to Ron, Tom, & Mike.

Steve Jones
Johnson City, TN [421.8, 168.5] AR
http://hbd.org/franklin





Return to table of contents


Date: Sat, 10 Apr 2004 11:55:11 -0400
From: Marc Sedam <marc_sedam at unc.edu>
Subject: 1/6 bbl Sankeys

Anyone know where I can find some of these?  I'd like to get 2-3 for 
home use and just got outbid by 11 seconds on f*&#$^) at ing eBay.

Cheers!
marc

- -- 

Marc Sedam
Life Sciences Consultant
Office of Technology Development
The University of North Carolina at Chapel Hill
308 Bynum Hall; CB# 4105
Chapel Hill, NC  27599-4105

919.966.3929  (phone)
919.962.0646  (fax)
OTD site :  http://www.research.unc.edu/otd
Monthly Seminar Info:  http://www.research.unc.edu/otd/seminar/





Return to table of contents


Date: Sat, 10 Apr 2004 13:25:56 -0400
From: "-S" <-s at adelphia.net>
Subject: Re: Enzyme Liquification process vs Starch liquification

Hey Fredrik,

I envy you your free time ....

> I have now arrived at a simplified liquification model for the starch,
which
> is the first step in the mashing process.
 ....
> The question how the liquification of the enzymes compare to that of
starch?
> For starch I assume an intermediate gel stage, and from gel to liquid
there
> is diffusion that is also promoted by stirring. I am assuming the enzymed
> are liquified faster than the starch, but somehow I need to quantify this.
I
> hoping someone has some info on this?

There is some complication here (well the whole mash is a massive
complication analytically).

I believe that any hydrolytic (lysis by water, OH- and H- group separation)
enzyme catalysis of the mash must consider the concentration of *FREE* water
as a factor in the Michaeilis-Menten rate eqn.   It's blithe to say that we
have x grams of starch and y grams of water - but the trouble is that all
the water molecules are not available for the enzymatic lysis.  When you
examine data of mashing conversion rate versus the amount of water you'll
see that there is a "knee" in the curve and at mashing concentration rates
much under  1 qt/lb or 2:1 that the rate of mash conversion is greatly
inhibited.

The explanation is this - amylopectic, the brached starch of the malt and
grist, ties up a *lot* water in the cleavage between the 1-6 and 1-4 branch
chains. These molecules are unavailable for hydrolysis, and this is a very
significant amount of water.  *Perhaps* the equivalent of the malt's mass
will be retained as unavailable water when the typical malt amylopectics are
gelled.  Anyone who has ever done a cereal mash realizes that raw grain
starch traps a load of water in amylopectic gel (8X to  10X the amylopectin
mass accordnig to some sources) and that this thick gel liquifies and
releases water as the amylopectins are enzymatically degraded.   The H2O
molecules are stuck in formation between the split starch chains. and either
alpha-amylase or beta amylase can reduce the extent of the cleavage region.

It's a separate issue but  I recently did a back of the envelope calc that
showed that very roughly 250ml of water (~1 US cup) of mash water is
completely used up in hydrolysis of a typical 12P 5gal mash starch.   This
water is lost in the mash and becomes part of the simpler sugar molecular
weight !  That's a lot of water !

Long story short - the amount of water available for mash hydrolysis isn't
close to being constant but varies in a complex way throughout the mash.
This in turn impacts the rates of hydrolysis.

> So far I am assuming the amylose and the amylopectin are liquified at the
> same speed. Would there be a problem with this assumption?

General background information (this is an HBD post) ... amylose is the
so-called straight-chained 1-4 linked starch, which in reality forms little
corkscrew curl shapes (not straight).  Amylopectin consists of mostly (95%)
1-4 linked glucose with the occassional 1-6 brach point thrown in roughly
every 18-22 glucose units - forming a complex messy snarl of curls.  Amylose
stains blue with iodine while amylopectin stains red-brown.  Barley and
wheat - like most grains - has starch made up approximately 75% amylopectin
and 25% amylose.  Some extrreme counterexample starches exist (waxy corn,
tapioca for example).

Marc Sedam can probably be more informative than I on the issue of
amylopectin gelatinization (hydration of amylopectic), but the
gelatinization of the amylopectin is roughly equivalent to it's becoming
subject to enzyme hydrolysis.  Despite the simplified POV in many brewing
books, this doesn't happen at some magically specific  "gelatinization
temperature" but can occur at lower temps over longer time periods.  The
point of the gel-temp is that for a particular grain nearly all of the
starch granules will have gelled by the spec-temp in a short time.. Calcium
has a role in gelatinization and high sugar concentrations can retard
gelatinization [again many confounding factors].  Barley gel-temp is 60-62C,
wheat 52-64C, malt 64-67C.

I can't quite ercall the details, but my recollection is that amylopectic is
soluble, but that amylose only forms a colloidal suspension, and that is
dependent on the size of the molecule.  The dextrans (say ~20 glucose units)
aren't problematic, but larger ones are difficut to 'float'.  This probably
has some small impact on the accessibility to enzyme hydrolysis.  There are
some details in a book on carbohydrates by Athel Cornish-Bowden.

So back to Frederick's question - at or above gelatinization temp both forms
of starch become rapidly available for hydrolysis ... in a few minutes.
M&BS pp 282 shows by graph that in 15 minutes at 65.5C essentially all the
available extract is in the wort.  At 49C (120F, well below gelat temp) it
takes about 2.5 hours to get half the goods into the wort.  A note on that
same page states that extended mashing at 55C (below gel-temp) will
eventually produce 90% of potential extract.  Cold water extract for base
malts runs around 20%-25%  of potential extract (much less for raw grain).
The amylose and amylopecting exists together in starch granules so it's a
fair bet that the ratios of these - even in cold water extract - is about
the same as for high temp mashing.

There are several distinguishable classes of starch granules in grains
(separated by size) but these are said to contain the same ratios of amylose
to amylopectin, tho' perhaps different gelatinization accessibility & temps.

A qualified yes - these two starch types should become accessible at about
the same rates.

> The activity graph for beta and alpha doesn't have the same scale, but it
> accounts for both the liquification and denaturation. During the enzymatic
> breakdown of the starch these activity curves will govern for the total
> enzyme concentration with time.

Very, nice Fredrik.  Obvious the activity scale isn't the same for BA and
AA, as there is something like 20X as much AA activity as BA activity at
peak.   I don't think the average HBer realizes how much excess AA is
available and how little BA on a relative basis in the mash.

> Note: the model isn't yet parametrized corrently. I have just thrown in as
I
> think "sensible" values that comply with the data I have seen so far.

I suspect that such methods are the only source of certain parameters -
don't apologize.

> If anyone has some info on the rate of liquification of alpha and beta
> amylase I would be very interested.

AA is developed in the malting process and BA exists in the raw barley.  The
malting process causes the BA to separate from a larger immobilizing protein
to which it is attached and separating from this "anchor protein" also
increases the BA activity by a factor of 20 or so.   The BA is distributed
throughout the starchy endosperm with higher concentrations toward the
center.  The AA is produced during malting, so it necessarily is
concentrated in the embryo portion of the seed, and then distributed along
the thin aleurone layer surrounding the endosperm.

It's a good bet that the AA enzyme goes more rapidly into solution from the
exposed aleurone of crushed malt than BA from the partly intact endosperm
but I have no data to support that.

> I figure I also need to account for the
> glucanase rest. I will do that very crude, and just assume that the
glucans
> suppress the rate of diffusion from the gel? I haven't found any info on
> this either?

There are a couple nice papers by Cynthia A. Henson and/or  Zhoutau Sun in
Archives of Biochem and Biophysics (one in v284 No.2, pp298-305, 1991) which
quantify the synergism between alpha-Amylase, beta-Amylase, debranching
enzyme and alpha-Glucosidase in barley.   This is apparently the first
quantitive study on the topic !   If you can't access this Fredrik,  send me
your mailing address by private email,

 -Steve





Return to table of contents


Date: Sun, 11 Apr 2004 18:07:57 +0000
From: bob.devine at att.net
Subject: Link of the week - gotmead 

Spring is a bit of an in-between season for homebrewers.
The heavier winter beer season is a bit past, the lighter
beers for a hot summer are not quite here yet.

So, mead sounds good.  This site offers lots of mead
related articles and recipes:
http://www.gotmead.com/index.shtml

Vicky's site is the typical labor of love common in homebrewing.
Help Vicky get past the "4000 visitors per month" level!

Bob Devine
Riverton, UT (round 2)


Return to table of contents

---