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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  Happy New Year! ("Pat Babcock")
  re: Yeast Reproduction Limit? ("Steve Alexander")
  Re: keg lube and leaks ("Gregor Zellmann")
  RE: Wort recirculation thru CFC ("Steve Alexander")
  Brix/SG (AJ)
  re: Something new (Bierschnapps) (Jeff)
  almond flavour ("M Millspaw")
  More Keg Lube ("Kirk Fleming")
  bottled porter carbonation (Demonick)
  Yeast Reproduction Limit ("Pannicke, Glen A.")
  Yeast Reproduction Limit? (Demonick)
  Rice Hulls (Cas Koralewski)
  Rose Hips Beer ("John Gubbins")


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Date: Mon, 31 Dec 2001 12:51:00 -0500
From: "Pat Babcock" <pbabcock at hbd.org>
Subject: Happy New Year!

Season's Greetings, Beerlings! Take me to your Holiday Ale...

We at the HBD wish all of you a happy, healthy, safe and prosperous New
Year! Be safe, consume responsibly.

Welcome to 2002!

- --
 -
All the best!

Pat Babcock in SE Michigan         pbabcock at hbd.org
Home Brew Digest Janitor           janitor@hbd.org
HBD Web Site                       http://hbd.org
The Home Brew Page                 http://hbd.org/pbabcock

"The monster's back, isn't it?" - Kim Babcock after I emerged
                                  from my yeast lab Saturday




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Date: Mon, 31 Dec 2001 03:58:47 -0500
From: "Steve Alexander" <steve-alexander at worldnet.att.net>
Subject: re: Yeast Reproduction Limit?

Dave King asks ...

>What governs the max yeast population in a primary?

A deficiency in a growth factor or presence of a growth inhibitor is the
only practical limit.  Yeast don't take a census and have no clue or care
about their population in any brewery fermentation context and don't
subscribe to "planned parenthood" either.

>[...]  But how do they
>know it's time to stop multiplying and time to make HOOCH?

This is a common misunderstanding.  Yeast NEVER choose between reproducing
and making ethanol.  Ethanol and reproduction are closely related (just as
for humans!).   Yeast produce ethanol as a by-product of fermentation.
Yeast ferment sugars into alcohol to get energy for reproduction and other
metabolic needs.

Well almost.  The exception is that yeast can, under rare circumstances,
derive energy from sugar without producing ethanol.  It's called
respiration, but it doesn't apply to normal brewing..  In brewing, yeast
will ferment the vast majority of the fermentable sugar into ethanol as they
reproduce.

In fermentation yeast take a wort glucose molecule (or produce one from a
maltose or maltotriose ...) and derive energy by degrading this to CO2 and
ethanol.    Reproducing yeast have huge energy requirements as they build
proteins and lipids for the new cells, so growing yeast convert lots of
sugar to ethanol to get energy.    We've all seen a stuck fermentation where
a once active fermentation slows to a crawl.  This happens when the yeast
are unable to reproduce because some critical "growth factor" is lacking.
Non-reproducing yeast cells don't die but require very little energy, so the
fermentation rate drops drastically when a growth factor is lacking.  It's
bad for the beer if this happens before the fermentables are used up.

What are the critical growth factors that can stop an active fermentation ?
Oxygen, amino acids (FAN) and fermentable sugars top the list.

One of the most likely growth limits for brewing yeast is oxygen.  In
brewery fermentations yeast take a big gulp of oxygen early in the
fermentation and then can reproduce 8 to 16 fold without any more oxygen.
If you pitch enough yeast that's the all the reproduction needed for a
complete fermentation.   Yeast use the oxygen to make sterols and
unsaturated fatty acids for healthy cell membranes.    If you underaerate or
underpitch then the yeast become sterol/UFA deficient before the wort sugars
are all fermented.  They stop reproducing and a stuck fermentation results.
The sterol deficient cells may also autolyze or produce more esters.

FAN or free amino acids are the building blocks for all proteins and modern
pale malts usually produce wort with enough FAN to allow  the yeast to
reproduce through the entire fermentation.   Conventional recipes with large
amounts of pale malt seldom are FAN deficient.  OTOH if you make a beer with
a lot of adjunct fermentables or use recipes with a lot of raw grain, then
you are in danger of stalling the fermentation before all the sugars are
fermented out.  Crystal and roast and some specialty malts typically do not
contribute much FAN to the wort.  When wort is FAN deficient the yeast may
be able, to a limited extent, to substitute other nitrogen sources for the
missing amino acids, but this can result in slow and odd fermentations
producing fusels.

Fermentable sugars are an obvious limit to yeast growth.   When the
fermentable sugar runs out the yeast lose their primary energy source and
reproduction stops abruptly.  This is exactly what brewers want - the yeast
ferments forcefully, growing without limitation right up to the point where
the fermentable sugars run out and the beer is completely attenuated.  This
is not the best situation for the yeast left behind, but that's another
story.

There are a lot (dozens) of minor growth factors like biotin, pantothenic
acid, zinc, copper, iron, calcium but these are rarely so deficient as to
cause brewing problems (perhaps zinc).

>The reason for the request was that I racked an IPA off the primary and
>dumped a fresh wort directly into that primary.  [...]
> I thought about not oxygenating, since I
>probably had plenty of the critters but I know the extra oxygen will get
>scrubbed out, so it won't hurt anything.

You should always aerate the new wort.  If you hadn't you might have had a
stuck or slow fermentation when your yeast ran out of sterols & UFAs.  Yes
you may have 3 times the normal amount of yeast, but if they are only
fermenting at 1/10th the normal rate you still have a problem.

 -S





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Date: Mon, 31 Dec 2001 10:46:58 +0100
From: "Gregor Zellmann" <gregor at blinx.de>
Subject: Re: keg lube and leaks

Kirk Fleming wrote:

> Once again, I'm embarassed to give
> English units, but I really don't have easy access this minute to
conversion
> tables and I'm too lazy to do the math.

No problem Kirk, I'm used to converting American units into metric, since I
started homebrewing and reading HBD, r.c.b. etc. :-)
Thanks to you and the other guys for answering my questions.
I will get some silicone gel at the scuba shop. I checked all my 4 cornies
(actually old Coca Cola pinlock kegs) on leaks with dishsoap and water and
found that it is just one o-ring. As I needed this cornie for beer a couple
of days ago, I used two o-rings on this peculiar lid and it seems to hold
pressure this way.

Cheers and Guten Rutsch

Gregor Zellmann
Berlin, Germany
[4247.6, 43.4] Apparent Rennerian





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Date: Mon, 31 Dec 2001 05:03:14 -0500
From: "Steve Alexander" <steve-alexander at worldnet.att.net>
Subject:  RE: Wort recirculation thru CFC

Steve Lane asks ...

>Is anyone flushing the boiling wort through the CFC and returning it to the
>boiler with a pump?

I've been doing this since I first got a pump several years ago.  It's a
very nice method of cooling the wort, but you are also (wastefully) cooling
the heavy hot SS boiler. I also sometimes hook up my old immersion chiller
in-line like Steve Jones does and trickle the outflow cross the hot boiler
exterior.  My objective is to quickly cool the wort so I needn't be
concerned with DMSO, and also to cool it enough that I can get very close to
tap water temps out of the CFC.  I haven't tried pitching & aerating in the
cooled boiler but have nothing against the method.

My only gripe is that the break particles are shaken, rattled and rolled.
The only way to leave the break behind is to cool, wait and rack w/ a
racking cane.  A pump won't  do it.  Another suggestion is to recirc
iodophor solution thru the pump, CFC and tubing for 20' prior to recirc'ing
hot wort.  Hot wort is not a sufficient sanitizer.  This step was critical
to getting a clean (no infection in unpitched wort after 72hr) wort test
from my system.

I don't understand when Steve Jones writes ...
>I pitched the yeast and continued
>to chill down to 65F. Then I diverted the wort to the
>fermenters. I must comment that this worked out very
>well, as I was able to run the valves wide open,
>and the wort was crystal clear.

Crystal clear pitched wort ?!!?  Yeast will cloud wort immediately and
significantly.  The wort can't be clear of cold break particulate either.
Perhaps there's no great harm in pitching and beginning the fermentation on
some break, but the stuff ain't clear by a long shot.

 -S

btw - I just heard from the long lost Dave Burley.  Dave has been battling
some very serious side effects from his arthritis meds, but is on the mend.




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Date: Mon, 31 Dec 2001 13:27:03 +0000
From: AJ <ajdel at mindspring.com>
Subject: Brix/SG

For Richard Perry:

There are dozzens of interconversions between Brix (Plato) and specific
gravity. A pair that receives little attention from the home brewing
community but which is certainly accurate enough for all but the most
demanding applications are the Lincoln Equations:

P = (463 -205S)(S-1) and S = 1 + P/(258.6 - 0.8796P)

where P is the weight of sugar per 100 grams of wort (i.e. the Plato
degrees which closely approximate Brix degrees) and S is the specific
gravity.

A. J.



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Date: Mon, 31 Dec 2001 06:38:16 -0800 (PST)
From: Jeff <duckinchicago at yahoo.com>
Subject: re: Something new (Bierschnapps)

In regards to breweries making other "distilled"
products.....
  >>>Anchor Steam has gotten on the distilled spirits
kick in a good way and sells a very interesting gin
called "Junipero" and a very-expensive Whiskey called
(I believe) "Old Portero".  Haven't tried either, but
have heard many good things about them.  Although I
have to say, for the price of the Portrero ($88), you
could buy an amazing single malt scotch or small batch
bourbon (or two very nice ones!)
  Anyone tried these?  (I know this is a beer forum,
but I figure Fritz is still 99% a beer guy.)



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Date: Mon, 31 Dec 2001 09:34:23 -0600
From: "M Millspaw" <mmillspaw at ameritech.net>
Subject: almond flavour


>Date: Tue, 25 Dec 2001 05:45:39 -0800
>From: "Schrempp, Michael" <michael.schrempp at intel.com>
>Subject: Bitter almond flavor
>Just put a Pilsner in bottles. At racking and bottling, it shows a slight
>almond flavor. Not too bitter, just almond. Is this an off flavor, or a
>desired flavor? The grain bill was 2 row weyermans, flaked barley, and
>crystal. I did a triple decoction (9 hours from lighting the stove to
>fermenter).

I had this happen once also, the beer was a CAP type with
a fair percentage of flaked barley. I used a Danish lager
yeast slurry [1/2 gallon] that I had gotten from my neighbor.
 I should mention that he had already fermented a beer with this 
same yeast and it did not have the almond taste, the beer
style and grain bill was quite different than my CAP. At the
time I attributed the problem to the 2 gen. yeast (and slowly used up 
the beer by boiling ribs in it). But after seeing the mention of the
 flaked barley in the above post, I wonder could that be a 
component of this off flavour? My mash was a step infusion 
starting at 122 F.

Micah Millspaw - brewer at large   





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Date: Mon, 31 Dec 2001 08:50:44 -0800
From: "Kirk Fleming" <kirkfleming at earthlink.net>
Subject: More Keg Lube

In 3826 "John Zeller" <jwz_sd at hotmail.com> suggested finding the source of
the leak rather than relying on Keg Lube to fix it. That's a good point--Keg
Lube (or any lubricant or sealant) isn't probably a leak 'solution'. Its
main utility for Corny kegs IMO is to lubricate ball valve O-rings to
prevent damaging them when placing and removing the connectors. I've found
that dry connectors against dry O-rings will often tear the O-rings.

Kirk Fleming
FRSL, FRSE




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Date: Mon, 31 Dec 2001 07:56:08 -0800
From: Demonick <demonick at zgi.com>
Subject: bottled porter carbonation

From: SLHMJL at aol.com
>I used Primetabs at an English Ale rate.  
>I put 3 tabs in a 16oz bottle, and 6 in a litre.

That's a very low carbonation rate.  3 PrimeTabs in a 12 ounce bottle
is about right for an English Ale that has been properly roused to 
degas the green beer.  

Chill the bottles as cold as possible without freezing, uncap, drop in 2
more PrimeTabs per 16 ounce bottle and 4 more per liter bottle, recap
QUICKLY.  You might drop in one more per bottle for the decapping gas loss.  
The tablets may induce foaming, though getting the beer very cold will help
alleviate the foaming.  Let warm to room temp.  There should be enough 
yeast left to do the trick in a couple of weeks.  

Domenick Venezia
Venezia & Company, LLC
Maker of PrimeTab
(206) 782-1152  phone
(206) 782-6766  fax
Seattle, WA
demonick at zgi dot com
http://www.primetab.com



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Date: Mon, 31 Dec 2001 10:58:12 -0500
From: "Pannicke, Glen A." <glen_pannicke at merck.com>
Subject: Yeast Reproduction Limit

Dave King asked about yeast reproduction limits:

>The reason for the request was that I racked an IPA off the primary and
>dumped a fresh wort directly into that primary.  Knowing that the 1st batch
>fermented vigorously, and it had only been in the primary for 6 days, still
>going strong, I figured the yeast were in great shape, but I still used my
>normal spray device from the cooled brew pot to the primary, which
>oxygenates the wort very well.  I thought about not oxygenating, since I
>probably had plenty of the critters but I know the extra oxygen will get
>scrubbed out, so it won't hurt anything.

Dave, it's a good thing that you aerated your new wort before dropping it
onto the old yeast cake.  Part of the flavor of beer is from the by-products
produced during the yeast growth phase.  Yeast require lipids for growth and
can manufacture them from the oxygen in your wort.  They can also get some
lipids from trub, but let's only consider bright, trub-free beer here.
During your first fermentation the yeast have reproduced a number of times,
used up all of the oxygen and lipid manufacture has ceased.  14 hours of
growth is the most often cited limit.  After lipid production ceases, the
yeast must then share the available lipid stores with their daughter cells
to continue reproducing.  This results in a logarithmic decrease in the
cell's lipid content and eventually reproduction ceases altogether.  In
previous issues of the HBD, Dr. Clayton Cone has put this lower limit
somewhere below 0.75% (with about 5% being the normal starting point for
active dry yeast).  Do the math here. 5% down to about 0.75% = approx 3
generations.

If you did not aerate your second wort, you would have dropped it onto
already "tired" yeast cells with little ability to grow and a lower alcohol
tolerance.  The lipids present in the cell wall also contribute to higher
alcohol tolerance.  Ergo, stuck fermentation.  By aerating your wort, you've
provided a nice little kick in the pants (do yeast wear pants?) to get
things moving again.  Fresh oxygen, more lipids, restored alcohol tolerance
and continued healthy growth...  

Now if you you're thinking of bubbling pure O2 or air through your wort
during the entire fermentation - don't.  It's a good way to grow yeast, but
a horrible way to make beer.  It will turn out acidic and nasty-tasting.
Try it.  Make a starter and continuously aerate it with a bubble stone and
an aquarium pump.  Then decant the beer and chug it.  Curiosity will kill me
yet!  A few shots of pure O2 at pitching, bubbling air into your wort for
the first few hours or adding freshly aerated wort to your fermenting beer
(around that magical 14th hour) should work fine.  I've tried this on a few
batches with no adverse results.  But I also don't know if I gained any
benefits either.  You may also see references to "dropping" your beer ala
Dr. Pivo.  I understand this to be racking to a second container with slight
aeration sometime around the "magical hour".  He claims good results with
this method.  My advice: not worth the time UNLESS you're doing a high
gravity beer (over 1.090 SG).  The yeast will need all the help they can
get!


Carpe cerevisiae!

Glen A. Pannicke

glen at pannicke.net          http://www.pannicke.net
75CE 0DED 59E1 55AB 830F  214D 17D7 192D 8384 00DD
"I have made this letter longer than usual,
because I lack the time to make it short." - Blaise Pascal







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Date: Mon, 31 Dec 2001 08:43:12 -0800
From: Demonick <demonick at zgi.com>
Subject: Yeast Reproduction Limit?

From: "Dave and Joan King" <dking3 at stny.rr.com>
>What governs the max yeast population in a primary?  I know the more
>healthy, the better the nutrients, the higher the population. They need
>oxygen during that stage, so good aeration is important.  But how do they
>know it's time to stop multiplying and time to make HOOCH?

The assumption underlying the last sentence is a myth.  Yeast will make
alcohol while multiplying.  Yeast will multiply under anaerobic conditions.
In wort, even highly aerated wort, respiration (that is metabolism without
making alcohol) is inhibited by the high sugar content of the wort.  
This effect is called the crabtree effect.  It is well known and well 
characterized.  Somehow the homebrewing myth got started and will not 
die.

During brewing yeast never respire unless you reaerate after fermentation
has slowed or stopped.  Aeration at this time will induce the yeast to
consume and oxidize the alcohol produced during the previous fermentation.
This leads to horrible, off-flavors.  I know - I've experimented with it
:-)

There are a few things that common limit the production of yeast in the
primary under anaerobic conditions.  When I say anaerobic I mean during
fermentation, even though the wort has been aerated, the yeast are NOT
respiring.  They are utilizing anaerobic metabolism. The oxygen is being
used for biosynthesis, mostly for fatty acids and sterols.  The primary
sterol is ergosterol and it is used to stabilize the cell membrane.  
Ergosterol can ONLY be synthesized in the presence of oxygen.  Once the
oxygen is consumed (within a few hours) the existing ergosterol is
distributed among more and more cells until its levels fall below that
needed for cell membrane integrity.  At this point the cells go to sleep.  
How is the ergosterol "distributed"?  As a cell grows the ergosterol
distributes itself evenly across the cell's membrane.  When the cell
divides, let's say into equal daughter cells, each cell inherits half the
ergosterol of the parent cell.  When the daughters grow and divide the
granddaughter cells inherit half of the half of the ergosterol.  If enough
of everything else is available, this ergosterol "dilution" will limit
growth.  

If you are interested in aerated yeast starters, check out the webpage
listed below.

Yeast also needs to produce proteins to grow and stay alive.  Since
proteins are long polymers of amino acids, protein synthesis requires free
amino acids (FAN) be available in the wort.  High temp mashes and some malt
extracts are low in FAN.  This can limit the yeast production in the
primary.

Other than running out of sugar, these are probably the most common "limits
to growth" (what ever happened to Paul Erhlich and the Council of Rome?)
encountered by homebrewers.  There may be some mineral deficiencies that
can limit yeast grwoth, and these are better addressed by others.

Cheers!

Domenick Venezia
Venezia & Company, LLC
Maker of PrimeTab
(206) 782-1152  phone
(206) 782-6766  fax
Seattle, WA
demonick at zgi dot com
http://www.primetab.com



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Date: Mon, 31 Dec 2001 16:22:43 -0500
From: Cas Koralewski <caskor at buckeye-express.com>
Subject: Rice Hulls

I am planning a Weizenbock and am going to use rice hulls to aid in the 
sparge. I'll do a protein rest at 130 F then saccharfication at 152 F. I 
also plan to do a decoction to bring the mash to a mash-out of 168 - 170 F.
My questions:
Will I experience any astringency from the rice hulls if I include them in 
the decoction?
When should I add the hulls?

Thanks,
Cas



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Date: Mon, 31 Dec 2001 20:53:44 -0700
From: "John Gubbins" <n0vse at idcomm.com>
Subject: Rose Hips Beer

Howdy folks,

Several months ago I asked about how to make Rose Hips Beer.  I got a
lot of
response and chose my method.  The stuff turned out to be excellent.
It took
a while to ferment and longer to bottle condition but it was ready by
Thanksgiving.  The folks at Thanksgiving dinner drank a case of it and
most of the rest was consumed at Christmas.  Normally I'm an all grain
brewer, but this one is a partial mash.  Here is the recipe:

I picked the rose hips in September in the Colorado mountains by Bowen
creek. They were nice and red and the freeze occurred a couple weeks
before.  They
don't taste like much a bit sour perhaps, but there is a flavor in
there.  I
sat around every night for a week before brewing with a grapefruit
knife and
dug the seeds out of them.  One at a time.

The Recipe:

Blue Meanie Rose Hip Ale

Brewed September 21, 2001

7 lb MF pale  LME  Couldn't get dried
2 lb Gambinus pale malt
half lb wheat malt
8 oz lt german xtal
4 oz light munich
2 oz 6.7AA Kent Golding  boil
half oz HG Cascade boil    HG is Home Grown
1 cup cleaned Rose Hips 15 min
half oz  HG cascade 10 min
White Labs Dry English Yeast

Started the yeast, .5 cup of DME to a pint of water the night before.
Boiled
the bottle and boiled the wort for about 15 min.  Boiled the top of
the pot
for the wort, too so that it is sanitary for cooling the wort.
OG 1.061 Pot Alc 8

Lower than anticipated gravity.  Perhaps I diluted it too much, but it
is a
solid 5 gal in the fermenter.  The wort has a thick heavy maltyness
that is
nicely balanced by the hops.  There is a fruitiness in there, too but
not
strong.  Rose Hips are not strong in flavor anyway.

9/28/01

Racked to secondary.  Gravity 1.010.  Tastes good, but not done yet.
There is
a fruity taste, very subtle but it tastes like rose hips.  The color
is redder
than it should be from just the malt.


October 2, 2001

Bottled.  FG 1.01.  This stuff is very good.  It has a taste I can't
identify
and is wonderful.  Must make this again.
- --------

So there you go.  Next fall when the freeze comes, grab some rose hips
and try
it.  It is well worth it.

What are these Rennarian Coordinates anyway?

John Gubbins n0vse at idcomm.com.





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