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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 2 ("Rob Moline")
  Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 3 ("Rob Moline")
  Rob Moline 2003.  Dry yeast varieties ("Rob Moline")
  Dr. Cone, 2003 - Lager Pitching Temperature (David Lamotte)
  Dr. Cone, 2003 (Eric)
  RE: Aerobic Yeast Propogation (Michael Hartsock)
  RE: Exploding CO2 Tanks, Really? (Michael Hartsock)
  Brain aneurysms and beer ("Dan Listermann")
  Chad's Father-in-Law (rickdude02)
  Re: Beer in NorCal/Sonoma ("Richard S. Sloan")
  Re: Double the Recipe? (MOREY Dan)
  Mash Step Time  and Mash pH ("Martin Brungard")
  Re: Aerobic yeast propagation ("Martin Brungard")
  Dr. Cone, 2003-barley wine-Harlan Nilsen ("Rob Moline")
  Increased Utilization with Larger Batches (MOREY Dan)
  Room enough for 10 gallons? ("Jennifer/Nathan Hall")
  Dr. Cone, 2003- bobz ("Rob Moline")
  Dr. Cone 2003, Training Yeast (Alexandre Enkerli)
  Dr. Cone 2003, Organic and Engineered Yeast (Alexandre Enkerli)
  Dr.Cone Responds-Jurriaan Boekamp ("Rob Moline")
  Dr. Cone Responds- Ken Schramm - Mead query ("Rob Moline")
  Dr. Cone Responds-wort oxygenation-Bob Devine ("Rob Moline")


* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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*   Beer is our obsession and we're late for therapy!   *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* * * * * * * *    COMING  TO THE HBD!    * * * * * * * *
*          Dr. Clayton Cone Fortnight of Yeast          *
*      8/11/03 - 8/22/03 Yeast Questions Answered       *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *

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Date: Wed, 13 Aug 2003 22:49:38 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 2

			Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 2

Also I've got a nutrition uptake related question

5) I've read that the uptake of nutritions, or at least FAN are restriced to
the lag phase that are put into pools used throughout the fermentation. And
that nutrutions that are added in the middle of fermentation is not
utilized. Is this true, and why? Are the transporters blocked or busy? Are
there special purpose transporters for amino acid uptake that are never used
for sugars?

Clayton:
Transports systems for amino acids are entirely different than for sugar
uptake and alcohol output.
Very little if any FAN is taken up by the yeast during the lag phase. The
majority of the FAN is utilized during the growth phase. As the alcohol
level builds up towards 5%, the yeast find it more difficult but not
impossible to take in nutrients and reproduce. So the growth slows down
dramatically and the yeast goes into a stationary phase and require very
little fresh nutrients. The best time to add nutrients is during the growth
phase.  Allow the yeast to consume the nutrients present in the wort then
add fresh nutrients during the last half of the growth phase. This is ideal
but not practical

And a question regarding sterol and oxygen

6) From books and articles I've read that sterol levels are important for
cell permeability. What are the details on this? Does low sterols cause the
wall to "leak", or to become unpermeable? Or does it simply cause some of
the transport mechanism to malfunct in general? What do you think about
modelling the effiecny of the transporters as increasing with sterols, so
that low sterols would basically be blocked and at a high enough sterol
levels the permeability would reach the ideal and maximum value?

Clayton:
Sterols act as a growth factor and will protect the yeast from alcohol
toxicity near the end of the fermentation. Sterols play a role in keeping
the cell wall fluid (rather than leathery). During the growth phase, the
cell wall must be fluid or elastic so that the bud can form. If the cell
wall is not elastic enough, the lack of sterols become a growth limiting
factor. Near the end of the fermentation the cell wall will become leathery
limiting the transport of sugar into the cell but more important it limits
the alcohol transport out of the cell thus the excessive alcohol in the cell
becomes toxic and will result in a slow or stuck fermentation.

I do not know how you will be able to control the rate of sterol production
or the total amount.  Yeast can produce the precursor squalene with no
oxygen, then with very little oxygen, 10 - 15 ppm, it can move squalene up
to sterol.

And a last but not least, a lag related question

7) Does the yeast absorb all oxygen and nutriutions, or at least until the
cellular pools for this are full before starting sugar uptake? Or can the
sugar uptake start in parallell even though at slow rate to supply extra
energy? Is it possible to set a condition for the start of sugar uptake?
Such are "all pools full", or "no nutritions left to absorb"? I have
considerd the case were the cells are very low on glycogen, and that the
energy supplies from glycogen simply are not enough to power synthesis of
sterols and other things during the lag phase - in such a case. Without
sugar uptake starting in parallell,
a) would yeast would be stuck in the lag phase forever?
or
b) Would it stop all nutrition uptake and synthesis due to lack of energy,
and instead start to uptake sugar - and NOT do any more nutrition uptake?

Clayton:
If the pitching yeast is healthy, there is enough of everything that the
yeast needs inside the cell to start the fermentation as soon as the lag
phase is over. The yeast will do many functions at the same time: metabolize
sugar, utilize the nitrogen sources, converting it into cell mass, enzymes,
DNA etc. Sugar is a nutrient for the yeast also.  During the growth phase it
metabolizes the sugar to receive energy and along with minerals, vitamins,
nitrogen produces cell mass. The yeast does not have to wait for a period of
time and a series of things to happen before it can start to convert sugar
to alcohol and CO2.

8) Does yeast synthesise sterols exclusively during the lag phase or can it
do so later on if there are enough oxygen and other building blocks in the
late part of fermentation?

Clayton:
There is very little activity in the lag phase other than acclimating the
yeast cell to its new environment.
Yeast produces sterols anytime there is oxygen available and there is a need
for it.

Thank you for your questions,
Clayton Cone

"The More I Know About Beer, The More I Realize I Need To Know More About
Beer!"
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Date: Wed, 13 Aug 2003 22:51:23 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 3

		 Dr. Cone/ Tobias Fischborn Responds - Fredrik-Part 3

Dr.Tobias Fischborn
Tobias
Questions 1, 2, 3 & 4:

   Glucose & Fructose is entering the cell by facilitated diffusion
(energy-independent). The driving force is the glucose/fructose
concentration gradient across the yeast membrane. The translocation is via a
permease (carrier protein) and the transport is coupled to the glucose
phosphorylation.
   Sucrose is transformed by invertase in the cell wall to fructose and
glucose
and then taken up by the yeast.
   Maltose is entering the cell by active transport (energy dependent)
driven
by the proton gradient (H+symport). ATPase expels protons (H+) which then
re-enter the cell with maltose. Glucose represses the maltose up-take and
its utilization. Glucose concentration higher than 0.4 % w/v impairs maltose
uptake by acting both as catabolite repressor and inactivator of maltose
permease. The maltose transporter is induced by maltose, repressed by
glucose (>0.4 %w/v) and inactivated following growth on glucose or by
nitrogen source exhaustion.
   Maltotriose is believed to have the same or similar active transport
system
as Maltose.
   There is a sequence in uptake since maltose and Maltotriose are inhibited
by
glucose.
   The transporters are induced by the sugar.

Tobias:
Question 5
   The amino uptake mechanism is similar to the maltose uptake (active
transport driven by proton gradient) but different transporter are used. The
uptake of some amino acids is repressed  by ammonium catabolites. The yeast
should still be able to use FAN at a later stage of the fermentation.

Tobias:
Question 8
   Oxygen uptake is at any time and sterol synthesis as well. That is what
we
are doing in our propagation.

Tobias Fischborn
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Date: Thu, 14 Aug 2003 00:06:45 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Rob Moline 2003.  Dry yeast varieties

			Rob Moline 2003.  Dry yeast varieties

Drew,
     The short answer is "Yes."

     The long answer is, "It's more complicated than that."

     No one could have been more perplexed than I at the reduction in
strains available, not just to the HB market, but also to the pro's. In
fact, the next batch of Brown Ale, one of our best sellers at CABCO is being
made with Nott, despite a history of Manchester.
     Simple truth....365 days in a year...only so many production runs in a
year. The more popular strains win out...be they wine yeasts...or
bakers....or London. Sad...but true.

     Yes, there are strains in development...Tobias and his crew work
wonders, and I can't wait. Unfortunately, neither he nor I make production
decisions.
     Believe me, sir, when I say no one looks forward to an expansion of
strains...or even just a renewal of the old ones more than I....no,
especially a renewal of the old ones.

     In Lallemand's defense, I will offer that while I might not have what I
want in strains...at least Lallemand is out here in the trenches with the
HBD....

     Beyond that sir...I can only add your voice to mine.....and forward
these comments....

Sorry, mate,
Rob
"The More I Know About Beer, The More I Realize I Need To Know More About
Beer!"

From: "Drew Avis" <andrew_avis at hotmail.com>
Subject: Rob Moline 2003.  Dry yeast varieties
Since we're on the topic of yeast... a question for Rob Moline (or maybe Dr.
Cone, I'm not sure).
For the past two years I've been using dry yeast for homebrewing almost
exclusively - ever since Paddock Wood started carrying the DCL dry lager
strains.  Before that I occasionally used Danstar/Lallemand Nottingham,
Windsor, London, & Manchester (the Nottingham always worked out well).  Now,
being a proud Canadian, I would love to buy my yeast from Lallemand, but
they don't offer the same variety (multiple lager, British ale, Belgian ale,
wit/hefe yeasts) as DCL.  In fact, Lallemand has *reduced* the variety of
dry yeast they offer to the homebrew market.
So my question is: is Danstar/Lallemand planning to develop or release any
new varieties of dry yeast in the near future?

Drew Avis ~ Ottawa, Ontario

"The More I Know About Beer, The More I Realize I Need To Know More About
Beer!"
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Date: Thu, 14 Aug 2003 19:54:46 +1000
From: David Lamotte <David at Craftbrewer.org>
Subject: Dr. Cone, 2003 - Lager Pitching Temperature

Dr. Cone,

I would like to add my thanks to you for your generous contributions, 
and to the previous posters for their thoughtful questions.

 From previous discussions on the HBD and a number of brewing texts, 
there appears to be two schools of thought regarding lager yeast 
pitching temperatures.

One suggests that you pitch a lot of yeast at or below the fermentation 
temp (8-12C) in order to minimise that amount of esters etc produced.

The other suggests that you pitch the normal amount at ambient room 
temperature and begin cooling down to your fermentation temperature once 
the first visible signs of fermentation begin.

My concern with the second method is that the fermentation will proceed 
at too high a rate unless you have a large 'cooling power' available.

Do you have any information on the effect that pitching temperature has 
on lager fermentations.

Thanks again,
David Lamotte
Fermenting in Newcastle, NSW, Australia





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Date: Thu, 14 Aug 2003 08:39:00 -0400
From: Eric <edahlber at rochester.rr.com>
Subject: Dr. Cone, 2003

Dr. Cone, Thank you for your valuable assistance to our homebrewing 
community.

I was hoping you could recommend ways of rapidly increasing cell density 
in slow growing yeasts like Brettanomyces. What little I have read about 
them mentions that they exhibit a negative Pasteur effect. How should I 
alter typical starter procedures for this unique species?

Eric Dahlberg
Rochester, NY



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Date: Thu, 14 Aug 2003 06:10:02 -0700 (PDT)
From: Michael Hartsock <xd_haze at yahoo.com>
Subject: RE: Aerobic Yeast Propogation

Simply stirring the yeast creates an aerobic
environement to encourage growth, as opposed to
anaerobic environments which are inherently created by
the by products of yeast metabolism.  The stirring, in
effect, creates a "well-ventilated environment."  I
simply pop the airlock and give my yeast a good
wake-up swirl.

Michael

=====
"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."



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Date: Thu, 14 Aug 2003 06:16:30 -0700 (PDT)
From: Michael Hartsock <xd_haze at yahoo.com>
Subject: RE: Exploding CO2 Tanks, Really?

The CO2 tanks are not capable of exploding.  Explosion
is not the danger; propulsion is the danger.  If
damage is caused to the valve stem of the tank, you
risk having a 1000+ psi steel or aluminum rocket fired
in an unpredictable direction.  Those things can go
through cinder block walls.  This is not an urban
myth, it can and does happen.  

I add another warning: don't pick up or drag your tank
by the valve.

Michael
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."



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Date: Thu, 14 Aug 2003 09:42:29 -0400
From: "Dan Listermann" <dan at listermann.com>
Subject: Brain aneurysms and beer

Chad Stevens writes about his late father-in-law death and the family's urge
to blame it on beer.  My father passed away a year ago in April at the age
of 74 from the same thing.  As far as beer goes, Dad had lost interest in
drinking during the last decades of his life.  His alcohol consumption was
pretty much limited to the very occasional taste of some of my beers or
wines.  Alcohol could not have played any role in his aneurysm.  Dad did
enjoy a lot of salt on his food.

Dan Listermann

Check out our E-tail site at www.listermann.com

Free shipping for orders greater than $35
and East of the Mighty Miss.






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Date: Thu, 14 Aug 2003 07:12:59 -0400 (GMT)
From: rickdude02 at earthlink.net
Subject: Chad's Father-in-Law

First let me say that I'm sorry for your loss, Chad.  If your 
Father-in-Law was the kind of guy to knock down 5 Tecates, I'm
thinking that you probably lost a good drinking pal in addition
to family member.

(Disclaimer:  I'm not a doctor, but an engineer.  I dropped out of
the pre-med program my Junior year because I thought that 
immediate income following graduation was preferable to 6-8 more 
years of school followed by years of debt payment.  Oh, to change 
such decisions!)

As for 3 days elapsing between that event and the aneurysm, well,
I think that speaks volumes.  If it was perfectly healthy tissue
then it would have recovered/healed by then.  If the break had
occured the day after, I'd say that it was probably the event 
itself, but even then it would have needed something to work 
with-- like tissue that was not elastic and made even more brittle
by the presence of heavy plaque.

On the common sense side:
If the constrictive effect of overuse of alcohol was capable of 
such damage, then we would be much more worried about that than
drinking and driving or alcohol toxicity.

I think your assesment is correct, Chad.  Although the alcohol 
may have been the straw that broke the camel's back, it certainly
wasn't the only culprit, and probably not the most significant,
either-- although possibly the last.  With a blood pressure like 
that, somethings got to give eventually.

Nonetheless, I wouldn't try to convince your wife or in-laws of
this right now.  I'm sure they need to blame something in their
grief.

Rick Theiner
LOGIC, Inc.




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Date: Thu, 14 Aug 2003 09:24:48 -0700
From: "Richard S. Sloan" <rssloan at household.com>
Subject: Re: Beer in NorCal/Sonoma

>> From: "Stefan Berggren" <yeastfarmer at hotmail.com>
>> I will be traveling in Sonoma and the surrounding areas
>> September 13-21st and would like to get some advice
>> on where a beer minded individual should go?

Bear Republic is a great pub. I'm sure you'll love it.
You might also want to check out -
Moylans in Novato (try the Moylans Special Bitter) http://www.moylans.com
Lagunitas in Petaluma Moylans in Novato http://www.lagunitas.com
Russian River Brewing (opening soon in Santa Rosa)
http://www.russianriverbrewing.com
3rd St. Aleworks in Santa Rosa
Getting up into Mendocino County you can find
Mendocino Brewing (brewpub in Hopland) http://www.mendobrew.com
Anderson Valley Brewing in Boonville http://www.avbc.com
North Coast Brewing in Ft. Bragg http://www.northcoastbrewing.com

I did this loop last year in Sept on day 3 & 4 of my beer vacation and had
a good time.
You can read about it here http://beeradvocate.com/news/stories_read/438/

Richard Sloan
Grosse Hund Brauerei
San Diego, CA




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Date: Thu, 14 Aug 2003 12:59:12 -0500
From: MOREY Dan <dan.morey at cnh.com>
Subject: Re: Double the Recipe?

Dave remarks:
>I find on my system the efficiency goes up 5-10% YMMV.

A ten gallon batch will have a higher thermal mass than a 5 gallon batch.
Assuming the mash vessel hasn't changed or has similar thermal resistance,
the larger batch should hold temperature better.  This may explain why you
have seen an increase in extract efficiency.  My last 10 gallon batch,
extracted about %10 more than expected (1.051 vs 1.049).  I attribute part
of the difference to base malt I was using (Dingleman's Pilsner).  I believe
I was using too low of potential extract value for the base malt.  Maybe
half (or 5%) of the increase was due to better thermal management.

Larry writes:
>The key adjustment involved a noticable increase in hop
>utilization, requiring me to reduce the amount of hops used.  This might be
>explained by the increase in the wort wolume, but I find it hard to
>understand why more alpha acid would get extracted in 12 gallons than in 6
>when the gravity is identical in both.

This is very interesting.  It is actually the opposite of what I would
expect.  I have found very little difference in my total evaporation between
a 5 gallon batch and a 10 gallon batch.  Regardless of the size, I boil off
about 1.35 gallons per hour.  I hope some day we all begin to quote
evaporation rates in volumes per unit time, not as percent per unit time.
It is a function of the brew equipment and the heat transferred to the wort.
The reason for discussing evaporation rates, is this should affect the
average boil gravity.    See digest #4154 and #4155 for more discussion of
evaporation rates.  A larger batch should start with a higher specific
gravity as the wort will be concentrated less because the total evaporation
is a smaller percentage of the batch size.  Based upon the various IBU
predictions available, one would expect a slightly lower utilization with
higher average boil gravity.  I'm not disputing your results, it just found
it interesting.


In summary, it appears for homebrewing scales that linear extrapolation is a
good starting point.

Prost,
Dan Morey
Club B.A.B.B.L.E.  http://hbd.org/babble
[213.1, 271.5] mi





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Date: Thu, 14 Aug 2003 14:06:56 -0400
From: "Martin Brungard" <Martin.Brungard at trow.com>
Subject: Mash Step Time  and Mash pH

At the recent National Homebrew Conference, there was an interesting session
conducted by Josh? Ebel of Two Brothers Brewing in Chicago.  One aspect of
that session really knocked me for a loop.  They only hold a mash step for 10
minutes before either stepping up or going to the mash out temp.  

He indicated they use a steam heated tun and they could do temperature
increases of about 1C per minute.  He did report that they still have a long
runoff time of about 90 minutes.  The surprising thing was that they report
88 percent efficiency with their mashing process.  

I have heard for many years that conversion occurs very quickly (~15 minutes)
for well modified malt.  But, I had not heard of anyone really using that
short of a mash step hold time.  

Based on that session, I've reduced my sacrification mash step hold down to
30 minutes instead of an hour.  I guess I'm not man enough to shorten that
step any further.   I've always used a short step with lower temp steps, so
that wasn't really affected.  I can report that my efficiency hasn't suffered
from the shorter mash when brewing identical beers.

It appears that the notion of long mash step times is not necessary.  I've
seen plenty of recipes that list 60 and 90 minute mash times.  Dropping an
hour or more off the brew day is very appealing.  I would like to hear from
others regarding the applicability of the method and any research that may
have been conducted on either the homebrew or commercial level.  Is anyone
else using really short step times like this?

In that session, he also reported that it is very difficult to have a too low
pH in a mash.  He reported that the malt's buffering capacity keeps the mash
pH from dropping below about 5.2.  This makes sense since there are acid
buffers as well as basic buffers in the world.  A lot of compounds can become
a buffer as the pH changes.   I was hoping that someone else had some insight
or confirmation of the malt/mash/pH phenomena.  So short of dosing the mash
with a lot of acid, it seems that a mash will be self correcting on the low

Martin Brungard
Tallahassee, FL


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Date: Thu, 14 Aug 2003 15:25:56 -0400
From: "Martin Brungard" <Martin.Brungard at trow.com>
Subject: Re: Aerobic yeast propagation

I read Fred Johnson's report on aerobic yeast propagation with interest.  Its
great to have folks out there with access to and interest in technical
brewing literature.  

I am a proponent of magnetic stirrers for yeast culturing.  I am also a
proponent of using oxygen for starters and batches.  The data Fred reported
did create a change in outlook in the way I will conduct my starters.  

Chris White reported at his National Homebrew Conference session that White
Labs produces their yeast stock using incremental feedings.  He also reported
that the wort gravity is kept at about 1.020.  He also has continuous
aeration and keeps it warm.  The thing that seems to differ from the
information that Fred reported is that I think that White Labs uses malt
extract for their feeding.  Fred's source indicates that molasses is a better
feed stock for the yeast in that it keeps the glucose level low.  Low glucose
keeps the yeast from making alcohol, creating cell mass instead.

Fred cited some data indicating that an incrementally fed, aerated molasses
wort is better at producing yeast mass.  But the data do not report what the
yeast production is if you just use aerated molasses wort without incremental
feeding.  Maybe its possible to provide one feeding of a molasses wort and
still get better results than with a malt wort?  I assume that a molasses
wort would have to be fortified with yeast nutrients for best performance.  I
wonder about the wisdom of using a molasses wort instead of a malt wort since
Fred's data indicated that it was for Baker's yeast.  Hopefully, someone can
comment on these aspects.

All of this information really firms up some changes that I need to
implement.  I think they may be useful for others to ponder.

1.  Oxygen definitely has its place in my brewing procedures.  It appears
most suitable for wort aeration for your beer batches.  You only want to hit
the batch with one or two doses of oxygen in about the first 12 hours after
yeast pitching.  But for a starter, you want continuous aeration.  My simple
oxygen regulator doesn't allow me to meter out really low continuous flows,
so my oxygen system is no good for continuous use.  It does appear that an
air pump with sterile filter would be the most economical and workable
solution to implement continuous aeration.  I agree that an aeration stone
may not even be needed when conducting continuous aeration.  A magnetic
stirrer is needed to keep the starter fully mixed so that the continuous
stream of air can keep the wort aerobic.

2.  I prefer dry malt extract for my starters since it stores well.  I know
it has the proper nutrients.  But it appears that incremental feeding is a
little more important with a malt wort since the glucose level is higher.
That means I've got to come up with some sort of sterile drip system to
continuously feed or I've got to make several little wort batches to add to
the starter periodically.  Sounds like I need to consider wort canning to
make pint wort batches to add to a starter periodically.  I am still
interested in hearing if a molasses wort is suitable for our use.

3.  The liquid remaining in a starter made with these procedures is
definitely not suitable for adding to a beer batch.  So dropping the yeast
out of solution and decanting the liquid is important.

Martin Brungard
Tallahassee, FL


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Date: Thu, 14 Aug 2003 21:17:24 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone, 2003-barley wine-Harlan Nilsen

			Dr. Cone, 2003-barley wine-Harlan Nilsen

Dr. Cone,
   I am planning on brewing a barley wine as soon as the weather cools off
enough so I can maintain a fermentation temp of 65-70 deg. F.  It will have
an OG of approximately 1.110.  I have purchased 3 paks of Nottingham yeast
(11 gm per pak) and am wondering if this should be enough yeast for 5
gallons.  I have been told that it may be too much yeast but I want enough
to promote a good healthy ferment.  I will aerate the wort well with pure O2
and add any fermentation aids that you may suggest.
   Thank you for sharing your expertise.
Harlan Nilsen

Harlin,
   It looks like you are going in for a very high gravity fermentation,
which
means that you will need to increase the yeast inoculum and provide adequate
nutrient supplementation. A 11 gram package of Nottingham can readily handle
five gallons of 1.048 OG wort, but would have a struggle handling 1.110 OG
wort. It would take two packets to comfortably handle this high gravity
wort. There is a general rule of thumb for inoculating a high alcohol (high
gravity) fermentation: one million yeast cells per ml. of mash per % sugar,
Brix or Balling. In the distilling and wine industry, OG, Brix and Balling
equals % sugar.
   This is not true in the brewing industry.  Part of the gravity is not
fermentable sugars, however, during the first part of the fermentation, the
osmotic effect is similar on the yeast growth.  Yeast do not multiply in
high gravity as well as they do in low gravity, so you have to make up the
difference by adding a larger inoculum.
   Please give special attention to the Nottingham yeast rehydration
procedure
written on the package. Success or failure often  starts with the
rehydration procedure.
   I am not sure how you achieved the 1.110 gravity wort; mashing, malt
extract
or pure sugar, so I cannot give you an exact answer regarding the amount of
nutrients that will be required. Pure sugar adjunct contains no nutrients
for the yeast and will require the most supplementation from a well balanced
nutrient source.  For your interest, yeast require 30% more nitrogen source
to ferment a 25% sugar juice than it does a 20% sugar juice. This shows you
the importance of giving careful attention to nutrient supplementation. I
would add 10 grams of a well balanced nutrient like Fermaid K / 5 gallons
wort.
   Regular gravity wort fermentation require about 8 ppm O2.  As you go up
in
gravity, the O2 requirement increases. You will need about 15 - 20 ppm O2.
How do you achieve this is a good question. Large breweries, wineries,
distilleries and research centers have good metering devices $$$. It takes
about an hour of pumping air, using an aquarium pump, through a porous
ceramic stone and just a few minutes using pure O2.  I have always been
leary of pure O2. You have to make sure that it is not hospital grade.  Some
hospital grade O2 contains a fungicide. Perhaps some of your colleges can
give you advise regarding aeration equipment and timing.
   Let me know how your barley wine turns out.
Clayton Cone
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Date: Thu, 14 Aug 2003 15:28:14 -0500
From: MOREY Dan <dan.morey at cnh.com>
Subject: Increased Utilization with Larger Batches

After thinking about Larry's comments some more, I believe there is a simple
explanation.  It is possible for utilization to decrease, but still end up
with more IBUs.  The following example is provided as an explanation.

Assumptions:
1.  Style	Robust Porter		OG	1.058		IBU ~35
2.  Kettle loss 0.5 gallons (wort that remains in brew kettle, below dip
tube)
3.  Water absorbed by hops in minimal compared to kettle loss.
4.  Evaporation loss 1.35 gallons/hr
5.  Boil time 60 minutes
6.  1 oz N. brewer at 9% AA for 5 gallons (2 oz for 10 gallons)
7.  Hops added at beginning of boil (30% utilization).
8.  Use Rager's hop formula

5 gallon batch (collected wort at 1.058)

Amount of wort at end of boil is 5.5 gallons at 1.058 (batch size + kettle
loss)
Volume at beginning of boil is 6.85 gallons (End of boil Volume +
evaporation loss)
Average boil gravity is 1.0517   ====>  1+ (0.058*5.5/((6.85+5.5)/2))
Gravity adjustment = 1.0085    ====>  1+((1.0517-1.050)/0.2)

IBU = oz * util * aa * 7462 / (end of boil volume * gravity adjustment)

IBU = 1 * 0.30 * 0.09 * 7462 / (5.5 * 1.0085) = 36.3 IBUs

10 gallon batch (collected wort at 1.058)

Amount of wort at end of boil is 10.5 gallons at 1.058 (batch size + kettle
loss)
Volume at beginning of boil is 11.85 gallons (End of boil Volume +
evaporation loss)
Average boil gravity is 1.0545   ====>  1+ (0.058*10.5/((11.85+10.5)/2))
Gravity adjustment = 1.0225    ====>  1+((1.0545-1.050)/0.2)

IBU = oz * util * aa * 7462 / (end of boil volume * gravity adjustment)

IBU = 2 * 0.30 * 0.09 * 7462 / (10.5 * 1.0225) = 37.5 IBUs  (increase in
bitterness)

In this example, the amount of hops was doubled as well as the wort
collected.  However, the amount of wort produced did not double.  It
increased about 91% (10.5/5.5 = 1.909), hops were increased more than wort
production.

Dan Morey
Club B.A.B.B.L.E.  http://hbd.org/babble
[213.1, 271.5] mi
  



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Date: Thu, 14 Aug 2003 21:29:34 -0400
From: "Jennifer/Nathan Hall" <hallzoo at comcast.net>
Subject: Room enough for 10 gallons?

Is it possible to ferment 10 gallons in a 12.2 gal TMS conical without
blowoff? I want to brew a 10 gal ale using WL California Ale yeast (in a 1
gallon starter). I haven't yet sealed the lid and made arrangements for a
blowoff setup. What would you think is the maximum volume you can ferment
without worrying about blowoff? Thanks for the help! I hope that those of you
on in the Northeast U.S. get your power back soon!

Nate Hall
BBV Brewery




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Date: Fri, 15 Aug 2003 09:38:43 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone, 2003- bobz

			Dr. Cone, 2003- bobz

   Thank you Dr. Cone for sharing your knowledge.
   If I want to "grow" yeast fast what would be your suggestions.
   I have read if you keep a constant temp, O2, limit glucose to >.4% with
stirring, yeast will stay in the resportory (growth) state and grow rapidly.
I have found limited info on the process.
   What would be the doubling rate if good constants were kept?
Thank you ------- bobz


Bob Z.
   You are almost right. Limit glucose to >.2%.
   Yeast do not grow faster under these glucose limiting conditions. They
grow
without the production of any alcohol.  This is important for the commercial
production of yeast.  They want all of the sugar and other nutrients to go
into cell mass.  Any alcohol produced is waste and ultimately becomes air
pollution as the huge volumes of air (thousands of cubic feet per minute)
blow through the growth media. On an average the yeast doubles about every
five
hours under these parameters. The growth rate is limited in order build into
each cell the exact composition (minerals, protein, glycogen, trehalose,
enzymes, DNA and etc) that is required to harvest a healthy yeast cell with
built in stability for storage life.  Also the growth cycle is limited the
last hours of fermentation to bring all of the cells into synchrony and stop
new buds.  The growth cycle could be shortened to 3 - 4 hours if cell mass
was the only criteria.
   Yeast can double in less than two hours in a non glucose limiting media.
Every yeast strain has its own genetically controlled growth rate.   The
growth rate decreases as the sugar concentration goes up.  A practical level
of sugar is 10 - 12 %.  A small amount of air is required. Shake flask with
a cotton plug will provide enough air.  Rich sources of nitrogen, phosphate
minerals and key vitamins increase the growth rate.
   In the early stages of commercial production of yeast the batch process,
with 10 -12 % sugar and a small amount of filtered air, is used.  Cell mass
yield is sacrificed in order to produce alcohol, which minimizes bacteria
infection.
   Glucose limited production of yeast offers greater potential for
infection
than sterilized batch process.

Clayton Cone
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Date: Fri, 15 Aug 2003 14:10:42 -0400
From: Alexandre Enkerli <aenkerli at indiana.edu>
Subject: Dr. Cone 2003, Training Yeast

Dr. Cone,
Like everyone else, I really do appreciate your help and understanding 
and I hope my questions won't be too silly for you.

We're told yeast will adapt to the medium, at least for scale. But does 
it also adapt to other characteristics of the medium? If so, would it 
be possible to lead a yeast strain to adopt different characteristics 
for further batches? If the adaptation is simply based on selective 
pressure and random mutations, one would imagine there's little that 
can be done.

Again, thank you for your help.

Alex, in Montreal
[555.1km, 62.8] Apparent Rennerian



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Date: Fri, 15 Aug 2003 14:16:32 -0400
From: Alexandre Enkerli <aenkerli at indiana.edu>
Subject: Dr. Cone 2003, Organic and Engineered Yeast

[Don't want to ask too many questions, and this one is really a matter 
of curiosity...]

Dr. Cone,
Noticed on the label for Wolaver's brown ale that 98% of the yeast was 
organic while 2% wasn't. Thinking about your comment on ADN markup, I 
was wondering if genetic engineering of brewer's yeast might be a 
significant field of yeast development.

Again, thank you.

Alex, in Montreal
[555.1km, 62.8] Apparent Rennerian



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Date: Fri, 15 Aug 2003 22:22:52 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr.Cone Responds-Jurriaan Boekamp

			Dr.Cone Responds-Jurriaan Boekamp
Dear Dr.Cone,
   At present I oxygenate my wort inline during cooling with pure (?) O2 as
I assume it to be as close to sterile as possible in a homebrew
situation and hence more practical than working with an aeration stone
and aquarium pump after cooling to pitching temp. Although I have not
experienced any problems with fermentation, I wondered what your views
on it would be regarding yeast health etc.
   Thank you for devoting some of your valuable time to answer questions on
the HBD.
Jurriaan Boekamp
Hobart, Australia


Jurriaan Boekamp,
   Both methods of introducing oxygen into the wort are satisfactory as long
as
you keep the dissolved oxygen in the 8 -15 ppm range. The oxygen transfer
rate from an air bubble into the wort is very poor.  The oxygen transfer
rate from an oxygen bubble is very good, so it is much easier to over
oxidize the wort using pure oxygen that it is using air. The pure oxygen
technique requires careful monitoring, using a very fine stream of bubbles.
   A small excess of oxygen results in an added increase of yeast cell mass
which is not bad but not desirable. It will effect the ester formation
slightly.  A larger excess of oxygen can place an oxidative stress on the
yeast cell, producing an unhealthy cell with possible undesirable by
products. The yeast has a mechanism called glutathione reductase to protect
itself against excessive oxygen.
   The aquarium pump method is inexpensive but carries with it the possible
sanitation problem. Good sanitation practices can take care of that.  The
pure oxygen technique is a Cadillac method but requires close monitoring.
   You have been successful thus far.  Apparently you have mastered the
correct
timing and flow rates.
   A colleague  of mine has always been leery about hospital grade pure
oxygen.
He noted that some hospital grade O2 contains a fungicide.  He uses
industrial grade oxygen.
   For your interest. The best time to introduce oxygen into the wort is on
the
second day of the fermentation.  The yeast need it the most at this time.
Some commercial breweries are beginning to adopt this technique. Double
batch fermentations automatically adds oxygen on the second day.

Clayton Cone
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Date: Fri, 15 Aug 2003 22:29:57 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone Responds- Ken Schramm - Mead query

			Dr. Cone Responds- Ken Schramm - Mead query

Dr. Cone, it is a privilege to be able to seek your counsel.
   I am curious about mead fermentations. I understand that the low
nutrient content of mead musts necessitate nutrient addition(s) to
insure vigorous and healthy fermentations.  I also understand that
staged additions of these nutrients over several days can improve the
performance of the yeast. In certain Lallemand strains, including one of
my favorites, 71B-1122, the reference chart indicates that this strain
has a low tolerance for O2 additions after the initial aeration.  Is it
best practice in the case of low O2 tolerance to continue using a staged
introduction of nutrients or to go with a single nutrient load at the
front end?
   I am also interesting in knowing what deficiencies in nutrient levels
lead to fusel alcohol production in wine or mead fermentations.  Can
specific levels of given free amino acids be tied to production of the
higher alcohols so seemingly common in mead fermentations?
   I see you have many brewers seeking your advice, so I will leave more
questions for a later date, if you have the time.
   Thanks very much for this valuable service.
Ken Schramm

Ken Schram,
   Most honey is low in nutrients that yeast find necessary for a healthy
cell
and a vigorous and healthy fermentation. Yeast do respond better to staged
additions over the first 1/3 of the fermentation. All the nutrients added at
the beginning will result in a high level of yeast cells with each cell
having a low protein content.  The fermentation will be vigorous in the
beginning then fizzle out towards the end.  Staged additions will result is
a lower cell population with high protein.  This will produce a steady
vigorous fermentation up to the very end. The high protein content in each
cell will protect the cell from alcohol toxicity near the end of the
fermentation. Staged or incremental additions of nutrients, namely nitrogen,
will also minimize the production of H2S.
   A better way to interpret the reference chart regarding 02 and 71B-1122
is:
the 71B strain requires less O2 for its growth phase than some of the
others. Excessive O2 is not toxic to this strain. The introduction of O2
with staged additions of nutrients is no problem.
   When there is an excess of amino acids the yeast catabolizes the amino
acids
via the Ehrlick pathway: deamination and decarboxylation to higher alcohol
referred to as fusel oils.  When there is a deficiency of amino acids, fusel
oils are produced by the biosynthesis pathway from pools of alpha-keto
intermediates.
   Each amino acid is tied in with a specific higher alcohol.  An over load
of
a specific amino acid should reflect itself in an increase of a specific
higher alcohol.

Clayton Cone
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Date: Fri, 15 Aug 2003 22:38:40 -0500
From: "Rob Moline" <jethrogump at mchsi.com>
Subject: Dr. Cone Responds-wort oxygenation-Bob Devine

			Dr. Cone Responds-wort oxygenation-Bob Devine

Dr. Cone, thanks for the expert assistance!
Question:
   Some British brewers "drop" their fermenting wort
up to a day after adding yeast.  How effective is this
for adding oxygen?  And how late can wort be oxygenated?
Bob Devine

Bob Devine,
   The optimum time to add oxygen to the fermentation is about 12 - 24 hours
into the fermentation.. Active Dry Beer Yeast(does) and re-pitched yeast
(usually) have enough lipids for two to three generations.  It is at that
time the budding yeast can most efficiently use the oxygen to continue to
bud and also produce enough lipids to protect itself against the higher
levels of alcohol. This is especially true with high gravity brewing.
   In wine fermentation it is not uncommon to add oxygen to a stuck
fermentation near the end of the fermentation when there has been inadequate
oxygen added at the beginning. The yeast will not grow but will metabolize
the oxygen to produce more lipids that will revive the elasticity or
fluidity of the cell wall and allow the transport of the alcohol out of the
cell to a safe lever and then begin to  transport sugar into the cell again.

Clayton Cone
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