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


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Contents:
  Re: Google map for HBD readers? (Nathan J. Williams)
  Re: Continuous aeration of starters (Fred Johnson)
  Re: Continuous aeration of starters ("Thomas T. Veldhouse")
  Beer Map (Google map for HBD readers?) (Alexandre Enkerli)
  Evaporation rates (Francisco Jones)
  Continuous forced aeration of starters not necessary (ALAN K MEEKER)
  Aeration Foam ("carl sherman jr")
  HHHC Competition Announcement (Tim Fahrner)
  Attaching a spigot to the boiling pot. ("eric")


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JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning,
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Date: 01 Nov 2005 01:02:32 -0500
From: nathanw at MIT.EDU (Nathan J. Williams)
Subject: Re: Google map for HBD readers?

Jeff Renner <jsrenner at umich.edu> writes:

> Bob Devine <bob.devine at worldnet.att.net> wrote from Riverton, UT:
> 
> > Suggestion: How about having a HBD reader page with a
> > Google map on hbd.org?  Did you ever want to quickly
> > find people near you?  Or see which club are close by?
> 
> I don't know nothin' about how to do this kind of stuff, but I love  
> the idea (no surprise here).
> 
> I hope someone will take a stab.

The current "cool kids" web site for this kind of thing is frappr.com,
which lets groups register a set of zip codes (or city/nation outside
the US) and view the results as a Google map.

If anyone wants to add themselves, I've created a Frappr map under the
group name "hbd".

http://www.frappr.com/hbd

        - Nathan


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Date: Tue, 1 Nov 2005 08:02:54 -0500
From: Fred Johnson <FLJohnson at portbridge.com>
Subject: Re: Continuous aeration of starters 

Mike asks about how to maximize the benefit of continuous aeration of
starters.

To push the yeast into yeast cell mass production and away from alcohol
production, the yeast must not be exposed to glucose concentrations
greater than 0.4%. If the glucose concentration exceeds this threshold,
the yeast will ferment the glucose into CO2 and alcohol regardless of
whether oxygen is present or not. The only practical way to feed the
yeast to avoid high concentrations of glucose is to continuously infuse
the medium at a rate less than the yeast can use it, but you must also
provide oxygen to maintain the growth. Otherwise, the yeast will
ferment the glucose even at low concentrations.

  From Malting and Brewing Science:
                                      Mass (kg)
                                    --------------
Medium   Conditions               Yeast Ethanol
Wort     Unaerated                 2.7  17.5
Wort     Aerated                   8.6  10.5
Wort     Aerated Incremental Feed 23    0.7
Molasses Aerated Incremental Feed 50    0

("Incremental Feed" in this case means repeated additions of 
progressively higher amounts of substrate but maintaining maximum 
levels of glucose below 0.4%. The ideal way to do this is to 
continuously infuse the substrate at a rate that is proportional to the 
mass and but no higher than will maintain glucose concentration at less 
than 0.4%.)
- --

Fred L Johnson
Apex, North Carolina, USA



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Date: Tue, 01 Nov 2005 07:50:31 -0600
From: "Thomas T. Veldhouse" <veldy at veldy.net>
Subject: Re: Continuous aeration of starters

Mike Sharp wrote:

>Recent posts on yeast have gotten me to wonder about continuous aeration of
>a starter.  I use an Ehrlenmeyer flask on a mag stirrer, and I've been
>thinking about using an aquarium pump with a sterile filter to continuously
>aerate while I stir. However, if I understand things correctly (which would
>be unusual in this subject area), this might not do me any good unless I
>also continuously feed the yeast.  Is that correct?  If so, and since I
>don't have a metering pump, could I approximate continuous feeding by giving
>the yeast little wort snacks periodically?  
>  
>
It has been my experience that you can get excellent yeast growth with 
just a charge of oxygen at the beginning, making the stir plate 
unnecessary as a matter of procedure.  However, if you have the 
equipment, then using it is probably an added bonus.  To get the air you 
need into the starter, it should be sufficient to simply put sterile 
cotton in the neck of your flask, or use another sterile filter if that 
makes you feel better.  The action of the swirling wort/beer should be 
enough to draw air into the flask.



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Date: Tue, 1 Nov 2005 11:02:25 -0500
From: Alexandre Enkerli <enkerli at gmail.com>
Subject: Beer Map (Google map for HBD readers?)

Our good friend Ben provided this link for a beer-related Google Map:
http://www.nhbrewers.com/mapbeer.html

Awe-some!
Now, would it be possible to add a category for homebrewers? Maybe 
hidden by default or some such, but it'd be incredibly nice to have 
that kind of visual aid. In fact, it'd be really neat to see how 
concentrated a beer scene might be, say, by how many brewers there are 
around a given brewpub...
And for those who worry about privacy, there's surely a way to give a 
blank number for the address (say "Western Ave, Northampton, MA, 01060" 
instead of "14 Western Ave, Northampton, MA, 01060").
And, just imagine if one could do a Google search for, say "homebrewers 
near Medford, MA"!

Ale-X in Bridgewater, MA
http://dispar.blogspot.com/
http://www.livejournal.com/users/enkerli/
http://blog.criticalworld.net/



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Date: Tue, 01 Nov 2005 10:39:26 -0600
From: Francisco Jones <frandog at earthlink.net>
Subject: Evaporation rates

Here's something I've been wondering about for a while:

I'm a heavy user of Promash, and it allows you to set your boil-off 
evaporation rate by either quantity per time ( ie gal/hr), or percent per 
time (ie 5%/hr).  I've been using the former, because using percent implies 
that the amount of water you lose in a given amount of time _changes_ as 
the volume in the boil pot changes.  In other words, as the volume in the 
boil pot decreases, with the percent fixed, less water is lost in the next 
time increment than in the previous time increment.  So boil-off is 
quadratic, or logarithmic, or whatever?  Not linear?

Why is that?  This is not intuitive to me, since it seems like with a given 
flame and pot opening, etc, I should get the same loss per time increment 
regardless of the volume in the pot (ignoring boundary value cases such as 
when the pot is almost empty).  Can anyone elaborate on why the percent 
method works, and which method is better or worse for particular situations?

I'm guessing that for large boil volumes, and for small total boil-off, the 
gal/hr method is an approximation of the percent method.  But I don't 
understand why.  Though it just occurred to me that this may be analogous 
to the situation of using a larger propane tank to get increased gas output 
even though the (ambient) temperature of the liquid propane is the same for 
a small and a large tank.  That is, more volume of liquid to liberate gas from?

Thanks.

Francisco Jones
Kankakee, IL
[256 magnetic/196 nm] AR

Temporarily writing from Houston, TX [226/923nm]




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Date: Tue, 01 Nov 2005 12:20:32 -0500
From: ALAN K MEEKER <ameeker at mail.jhmi.edu>
Subject: Continuous forced aeration of starters not necessary

Mike Sharp asked about forced aeration and continuous feeding
of yeast starters grown on a magnetic stir plate. Mike, this is 
not necessary. It's a waste of effort and, as a potential source
of contamination, may do more harm than good. 

With mildly vigorous stirring and a loose fitting cover the starter
will get all the oxygen it needs for healthy growth by the magic of
diffusion. I was worried about the same thing when I started making
starters on a mag stirrer but they grew up quite nicely. I also did an 
experiment that convinced me there was nothing to worry about. I
made up a starter using glycerol instead of glucose as the sole 
energey source. Brewer's yeast cannot ferment glycerol, they 
can only utilize it by aerobic respiration, thus sufficient oxygen is
an absolute requirement. The glycerol starters grew up well, indicating
that they were getting plenty of oxygen just from the action of the stir plate.

The continuous feeding you are referring to is used in industry to 
maximize the biomass (yeast) yield with glucose-fed yeast under aerobic
conditions. The goal is to keep the glucose concentration down below the 
level which induces the Crabtree effect in which yeast will ferment glucose
to ethanol even in the presence of oxygen. 

We homebrewers really should not be growing our starters up in glucose-
based starter media, rather some sort of wort should be used. Wort is 
relatively glucose poor, so the yeast will quickly eat up the glucose and 
then enter into an aerobic respiration phase. This will also avoid the 
potential loss of maltose (the main utilizable sugar in wort) utilization
capability which may occur in yeast cultures grown in media which 
only contain glucose as the sole energy source. This would obviously be
a bad thing to lose going into the main wort fermentation. 

Alan Meeker
Lazy Eight Nanobrewery
Baltimore, MD


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Date: Tue, 01 Nov 2005 14:16:08 -0500
From: "carl sherman jr" <rsherman69 at hotmail.com>
Subject: Aeration Foam

Beginner, first post

I am using an aquarium pump and stone to aerate my wort in the fermentor.  I
have read that you must wait for the foam to subside before pitching the
yeast, but can not find any reasoning for this.  During aeration, I have to
stop before the foam comes out the top of the carboy.  I have waited for the
foam to subside, but this takes quite a while, and I am afraid of
contaminating the wort.

Should I seal the carboy with an airlock, and wait for the foam to subside.
Should I pitch the yeast with the foam still in the carboy?

I can't seem to find anything further on this subject.  Any help will be
appreciated.

Rich S.  Scranton, PA




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Date: Tue, 01 Nov 2005 14:37:28 -0600
From: Tim Fahrner <fahrner at pathology.wustl.edu>
Subject: HHHC Competition Announcement


Just a note to the readership that registration is now open for the 14th 
Annual Happy Holiday Homebrew
  Competition. Official announcement to follow:

Have the ultimate holiday homebrew? Enter it and your other fine beers in 
the St. Louis Brews'
  Happy Holiday Homebrew Competition, one of the biggest homebrew 
competitions in the Midwest.
This year it will be held on December 10, 2005 at the Parish Hall of Our 
Lady of the Presentation
Catholic Church in Overland, MO. So you think your brew can be a contender? 
Find out by entering it
in the HHHC 2005. It's  AHA & BJCP sanctioned, and we are proud to be the 
final qualifying event for the
Eighth Annual Masters Championship of Amateur Brewing.

Please see our website, stlbrews.org, for more information.

Vital details in brief:

Fee: $5.00

Entry Deadline: 11/1/2005 - 12/3/2005

Awards Ceremony: 12/10/2005

Sanctioned by BJCP, AHA

  MCAB Qualifying Event

Contact: David Nitzsche

Phone: 314 918 1929
  



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Date: Tue, 1 Nov 2005 19:32:50 -0700
From: "eric" <zeee1 at nebonet.com>
Subject: Attaching a spigot to the boiling pot.

Hello all

 I recently asked about stirring the cooling wort with the immersion coil,
then pouring my cooled wort through a funnel.
  The replies suggest that siphoning or using a spigot would help to reduce:
1, the chance of contamination and 2, the amount of trub going into the
fermentor.
 If I go the spigot route with a tig and stainless fittings, is it suggested
to attach the fitting as close to the bottom as I can, assuming the trub
will pretty much stay in the middle of the pot, or should it be mounted a
little high? Threaded short piece of tubing for a thread on valve?
 I have been putting the funnel and strainer in sanitizer, then rinsing off
and putting the coil, strainer, and funnel in the boiling wort for the last
10-15 minutes for sanitizing.
 Also, I am "rereading" Papazian. I also have a Dave Miller book. Any
recommendations for others?

Eric

Deweyville, UT



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