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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  FOY-2004-Response - Reusing Yeast (jethrogump)
  FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine (jethrogump)
  FOY-2004 (jethrogump)
  More Sugar Confusion ("Phil Yates")
  Galv Gas Pipe (Moses Rocket)
  Re: PH adjustments ("Martin Brungard")
  BONES Bash 2004 Competition (Bruce Millington)
  serial vs parallel ("Dave Burley")
  Sources of FAN (free amino nitrogen)? (Bill Velek)
  link of the week - Australian craft brewing (Bob Devine)
  New Hop Information Resource ("Scott D. Braker-Abene")
  FOY - Rescuing Old Yeast (Grant Family)


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*               A Fortnight Of Yeast                    *
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*      Questions submission: 10/11 - 10/22/2004         *
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Date: Sat, 23 Oct 2004 03:55:43 +0000
From: jethrogump at mchsi.com
Subject: FOY-2004-Response - Reusing Yeast

FOY-2004-Response - Reusing Yeast

I have begun to reuse liquid yeast from my homebrewing and was
wondering whether it is better to save yeast from the primary 
fermentation or the secondary fermentation?  I've heard that it
is a decision whether to save "dirtier but vigourous yeast cells", or
"cleaner but  tired yeast cells".  What is your opinion on this?
keep in mind that I typically do not perform a washing 
procedure on the saved yeast.  It is stored in a sterile Mason 
jar. When I am ready to brew,  I make a starter, bring it back
to life and pitch.  
Thank you very much for your time. 
William Erskine

William,
Most commercial brewers harvest the yeast from the main/primary
fermentation while the yeast from the secondary fermentation is
discharged.  But their wort is in general "pre cleared" in a whirlpool,
separator or sedimentation tank. Their crop yeast is not as "dirty" as
in home brewing and often they wash their yeast as well before
re-pitching it. So yes I would agree that in home brewing the yeast from
the secondary fermentation is cleaner than the crop yeast from the
primary. 

If the yeast from the secondary fermentation is weaker I am not so sure.
Usually you transfer the yeast that is still in suspension to secondary
fermentation. This is the vital yeast whereas the exhausted yeast cells
settle to the bottom. So at the beginning of the secondary your yeast is
at least as vital as the crop yeast from the primary. Then it depends
when you harvest the yeast. If you harvest the yeast as soon as the
secondary fermentation is finished the yeast should still be vital but
if you leave the yeast for a long time in your beer than it might not be
worthwhile harvesting the yeast. 

You also have to consider that there is lower yeast concentration in
your secondary fermentation than in your primary, means you might have
not enough yeast to start the next fermentation.
Regards
Forbes & Tobias 


Return to table of contents


Date: Sat, 23 Oct 2004 04:07:48 +0000
From: jethrogump at mchsi.com
Subject: FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine

FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine

Dr. Fischborn and Dr.Waldrop. Some time ago I was counting 
cells and then looked at the datasheets for windsor and 
nottingham and it says(among other things:):
Nottingham contains >= 5 billion viable cells / g(dw) 
Windsor contains >= 7 billion viable cells / g(dw)

This got me curious. I have come up with two interpretations 
of this, either that the nottingham cells are simply bigger and 
you only get so many into a gram, or the nottingham strain 
are more sensitive to the drying process in the sense that you 
get a little bit more dead cells per gram.

1) Can you explain why there are more windsor cells/g than 
nottingham cells?
2) Setting aside viability, what is the typical actual total cell 
count per gram Nottingham?
( I did a count some time ago, and though my methods are very 
crude and homemade (using estimates drop volumes), and may 
give errors, I arrived at a much higher count, around 
20 billion/g. It did only one count, so there may have been error, 
but I am doubtful that my error is that large, or if the numbers 
you guarantee are rather on the low side to be safe? I never 
repeated the experiment so I could have been in error, but it
would be nice if you can confirm what is the excepted actual
total cell count, rather than the minimum guaranteed viable cell 
count)
3) I have tried to determine the glycogen contents of yeast slurry,
by means of taking a digital picture of the iodine stained cells, 
and then translate the colour scale into a relative glycogen value 
(0-100%). Just  looking at the colour resolution I think it might 
be realistic to resolve the glycogen level to maybe 4 intervals, 
0-25%, 25-50%, 50-75%, 75-100%.

What do you think about this? Is the correlation between 
intensity of the staining and glycogen level good? These are one 
of the few the relatively simple methods that does seem practical 
for any homebrewer with a microscope and interest since you 
don't need any hard-to-get chemicals or other lab equipment. 
The question is, is it reliable for ballpark estimates of glycogen? 
(provide the camera exponation settings are the same)

In my firsts tests the glycogen drop I arrived at seemed to make 
sense. It dropped from the 75-100% range to the 25-50% in two 
days starving at room temp in a closed bottle (noO2). Does this 
make sense to you?

http://hem.bredband.net/frerad/beer/modelling/pictures/glycogen.jpg
(the optics in my simple microscope is limiting, that's why it's blurry)

The pics are actually from a way outdated pack of windsor that I 
had saved for experiments. The low glycogen, left is the outdate 
pack. The right picture is how the outdated pack looks like after 
getting a little bit of sugar to eat. Once the sugar finished and 
two days later  at roomtemp (still on under the beer) the level had 
dropped significantly judging from the colour.
/Fredrik

Fredrik,
Yes, Nottingham yeast has usually larger cells than Windsor yeast and Lager 
yeast has even larger cells than the Nottingham. The viabilities mentioned on 
the technical data sheets are minimum viable cells per gram that we guarantee 
determined by plate count on YPD-agar. Usually the viability is higher. There 
is a slight difference in how resistent the different strains are to drying 
and rehydration. Usually ale yeast strains are more resistent than lager yeast 
strains.
You might also consider that you will find much higher cell numbers under the 
microscope than by plate count, even if you have 100 % viability because you 
do not always have a single cell forming a colony but rather two or more 
cells. 
For Nottingham yeast the average cell count under the microscope is around 20 
to 30 billion cells per gram dry yeast. 

As for the glycogen pictures you showed, this is quite interesting and there 
have been attempts in the past to use image analysis in such a way.  Using the 
level of glycogen in this manner is quite simple but perhaps the scale you are 
using may be a bit confusing or misleading.  I believe you may want to 
recalibrate your scale.  Glycogen can be analysed in the yeast but I would 
guess you could reduce your scale by a factor of 2.5 and you may not be too 
far off. Certainly brewing yeast have been known to accumulate up to 40% 
glycogen.
Regards
Forbes & Tobias


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Date: Sat, 23 Oct 2004 04:20:23 +0000
From: jethrogump at mchsi.com
Subject: FOY-2004

Folks,
Am currently traveling and doing this by web-mail, not my fave....
Please excuse any glitches...
Gump


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Date: Sat, 23 Oct 2004 22:43:30 +1000
From: "Phil Yates" <phil.yates at bigpond.com>
Subject: More Sugar Confusion

Alan Meeker comments:
>My associate Phil Yates asks, what /practical/ use is there in discussing
>the details of yeast sugar utilization? Well Phil you are correct, this
>topic isn't likely to have much (if any) practical benefit to the average
>homebrewer.

Well thanks Alan, at least you are honest enough to answer my question. I'm
certainly not suggesting that technical discussion should not exist on HBD.

>Remember, the PgDn key is
>always nearby... :)

Well it was, but after years of using it whenever Mr "S" popped his head up,
it eventually welded itself to the key board and I had to have it surgically
removed.

Now I'm puzzled by this post:

>dglucose/dt = - fg(x)*glucose*yeast_active +
>+ 0.5 * [ - fs1(x)*sucrose*invertase_wort -
>fs2(x)*sucrose*invertase_surfacebound ]

>dfructose/dt = - ff(x)*fructose*yeast_active +
>+ 0.5 * [ - fs1(x)*sucrose*invertase_wort -
>fs2(x)*sucrose*invertase_surfacebound ]

>dsucrose/dt = - fs1(x)*sucrose*invertase_wort
> - fs2(x)*sucrose*invertase_surfacebound

>dmaltose/dt = - fm(x)*maltose*yeast_active
>dmaltotriose/dt = - fmt(x)*maltotriose*yeast_active

Clearly, I have been reading the wrong brewing books and missed out on such
simple brewing details. By some stroke of fate, I've been brewing bloody
good beer without understanding any of the basics at all.

I really must do something about my ignorance. You just can't carry on
enjoying your beer all your life!

Phil








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Date: Sat, 23 Oct 2004 06:40:44 -0700 (PDT)
From: Moses Rocket <mosesrocket at yahoo.com>
Subject: Galv Gas Pipe

Black schedule 40 steel pipe is generally your safest
bet for gas piping, but it is not mandatory as some
here seem to think.  There is generally no problem
using galvanized steel pipe for gas piping.  Most
building codes in the US and Canada now allow either
black or galvanized for gas piping, as well as soft
copper tubing and the new flexible plastic coated
stainless steel tubing (CSST).  (But check with your
local code office, they may still have old antiquated
codes on the books)  There are a couple of things to
watch out for: Copper tubing can not be used if the
gas supply contains more than an average of 0.3 grains
of hydrogen sulfide per 100 standard cubic feet. 
Hydrogen sulfide can cause corrosion and embrittlement
in copper.  (Most gas supplied these days has had any
hydrogen sulfide removed so this is rarely a problem,
check with your gas company)   Copper tubing with
flare fittings is a whole lot easier to work with than
heavy black or galvanized steel. Galvanized pipe was
not allowed in the past because many waterlines in
houses were installed with galvanized pipe.  Black was
specified for gas to tell it apart from the
waterlines.  Nowadays, galvanized steel is seldom used
for waterlines, so the codes have changed and now
allow galvanized for gas lines.  Many codes do require
that exposed gas piping that is NOT in black steel be
identified with a yellow label marked GAS, to avoid
confusion (or you could just paint it black).  

M.R.




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Date: Sat, 23 Oct 2004 06:31:04 -0800
From: "Martin Brungard" <mabrungard at hotmail.com>
Subject: Re: PH adjustments


John Peed asked for advice regarding acid usage in his brewing practices.  
He mentioned he was adding acid to reach a specific pH's prior to brewing.  
As John found out, this is not always the best approach.  The need for 
acidifying is highly dependent on the properties of the water and on the 
darkness of the grist.

I've got the feeling that John didn't need to acidify every beer he brewed.  
The most important aspect of water that every brewer should understand is 
Residual Alkalinity (RA).  This is an interplay of hardness, alkalinity, and 
mash grist.

I did a quick check on the water supply for Oak Ridge, TN.  It is a surface 
water source, but it flows through carbonate rock terrain.   I could not 
find the important water data like alkalinity and hardness, but would expect 
that these level are low to moderate.  It is possible that this water has a 
favorable RA to begin with.  In this case, acidification for the mash is not 
needed.  If a darker beer is brewed, then acid is definitely not needed.  
Acid additions are more important with the light colored beers and 
decreasingly important as the beer darkens.

Hardening the brewing water with gypsum doesn't acidify water by itself, but 
it does reduce the mash pH in conjunction with the grain.  The net effect is 
that the RA of mash is reduced to a more appropriate level.  This effect can 
be counterproductive if the beer being brewed is dark.  Then, the natural 
acidity of the dark grain can push the mash's RA too low.  In this case, 
chalk or sodium bicarbonate may be needed to moderate the dark grain 
acidity.

I have to admit that I've overdone acid additions and I've added acid to 
dark grists that didn't need it.  In either case, the beer is a bit thin and 
tangy.

Acid additions need to be performed with an understanding of its effect.  As 
John found through experimentation, maybe he doesn't need it for every beer. 
  Rob Beck correctly pointed out that phosphoric acid has less flavor than 
lactic acid.  That can help if your water composition requires you to add a 
lot of acid, but I think that the real problem was that acid additions were 
not really required for most of the beers John brewed.

The first step in figuring out what should be done with your brewing water 
is to get the water report.  You need to call the water utility (or get a 
water test) and ask for the concentrations of hardness, alkalinity, and 
major flavor ions.  You'll then be able to make a better assessment of what 
is really needed for brewing.


Martin Brungard
Tallahassee, FL




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Date: Sun, 24 Oct 2004 09:30:19 -0400
From: Bruce Millington <bmillington at verizon.net>
Subject: BONES Bash 2004 Competition

The Brewers of the Northeast Section proudly announces the return of the 
BONES Bash, to be held Saturday, November 6, 2004, at the Nodding Head 
Brewery & Restaurant in downtown Philadelphia, PA.  This will be the 
first leg of the Delaware Valley Homebrewer of the Year.  Entries will 
be accepted from October 10th thru November 1st, 2004.  First place 
winners will receive prizes.  For full details, please go to:
www.hbd.org/bones/

We will be using the 1999 BJCP guidelines.  We are in desparate need of 
judges  All interested judges and stewards please contact Bruce 
Millington at bmillington at verizon.net.  Judges and stewards are to 
report by 8:30AM, and begin at 9:00AM.  See you at the Bash!

Bruce Millington
Judge Coordinator


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Date: Sun, 24 Oct 2004 11:16:54 -0400
From: "Dave Burley" <Dave_Burley at charter.net>
Subject: serial vs parallel

Brewsters:

Well, I guess Alan's "exasperation", call it what you will, is not so well 
placed after all.

 He agrees with me that glucose does not block the assimilation of fructose, 
which means to me they are asssimlated in parallel. Which is what I said from 
the beginning of this discussion with Fredrik.  I also pointed out that 
glucose did block some sugar type assimilation in those modelling discussions 
with Fredrik..

As to why this is important to brewing, I can't say, except that it is an 
extension in our mutual interests in brewing and it may be important to 
someone, someday.

But if we are going to discuss it let's get it right in all aspects and help 
each other understand this complex process in detail. That is the point of the 
HBD, not to make these scientific issues personal

Keep on Brewin'

Dave Burley




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Date: Sun, 24 Oct 2004 12:30:57 -0500
From: Bill Velek <billvelek at alltel.net>
Subject: Sources of FAN (free amino nitrogen)?

Well, unfortunately I missed the FOY, but perhaps someone can still 
answer these questions about yeast.

First, I assume that commercially produced yeast nutrient probably has 
FAN included in it, probably along with zinc and magnesium, etc.

Second, there has been previous discussion some time ago about adding 
quantities of dried yeast to the boil -- with the really cheap baker's 
yeast (2 pounds or almost a kilo for a bit more than $3.00 U.S.) being a 
very economical way to do that.  [I realize there is special yeast made 
with extremely high zinc content, but I'm speaking now of just baker's 
yeast, or perhaps old packets of regular brewer's yeast.]

Questions:

1.  Does boiling dried yeast provide FAN, or just minerals?

2.  Assuming that boiling dried yeast does provide FAN and minerals that 
yeast need to grow, how much dried yeast would be the _optimum_ amount 
to add to the boil when making a 5 U.S. Gallon batch (19 liters)?

3.  Besides yeast nutrient, and perhaps dried yeast, is there any other 
source of FAN that is readily available as an adjunct?

Thanks.

Bill Velek



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Date: Sun, 24 Oct 2004 12:26:15 -0600
From: Bob Devine <bob.devine at worldnet.att.net>
Subject: link of the week - Australian craft brewing

Our homebrewing friends in Australia have put together
a nice website on homebrewing.  Recipes, style histories,
and other brewing tidbits are all there.

   http://oz.craftbrewer.org/

Bob Devine
Riverton, UT


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Date: Sun, 24 Oct 2004 14:49:18 -0700 (PDT)
From: "Scott D. Braker-Abene" <skotrat at yahoo.com>
Subject: New Hop Information Resource

Hey Now,

I got tired of opening the EVIL PDF files and compiled a DB onto a webpage of a
whole bunch of various Hops and their important specifications and such...

You can find it here:

http://www.skotrat.com/skotrat > Hop Information

and here:

http://www.brewrats.org > Hop Information

I will be cleaning up some of the displays over the next couple weeks...

I hope that you use it and find it usefull in your brewing process.

C'ya!

 -Scott

=====
"I can't help it... I love being a fart machine"
 - Heather Braker

http://www.skotrat.com/skotrat - Skotrats Beer Page
http://www.brewrats.org - BrewRats HomeBrew Club


		


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Date: Mon, 25 Oct 2004 09:45:58 +1100
From: Grant Family <grants at netspace.net.au>
Subject: FOY - Rescuing Old Yeast

G'day Drs,

About while ago I was bottling a batch of hefeweizen and wanted to
reserve some yeast from it. My method was to rinse about 100mL thick
yeast slurry in cooled boiled water once or twice, removing as much trub
as possible, before leaving it under a 300mL layer of cooled boiled water
and storing in the fridge at 1C. The strain was White Labs Hefeweizen
(WLP300).

I didn't intend on leaving it so long, but today, about 7 months later, I
made up a 250mL batch of ~1.035 SG wort with some Wyeast nutrient
and pitched it onto the yeast (I poured off the water first). It's in a small
plastic bottle and I am squeezing air in and shaking it to introduce as
much O2 as possible. It's now fermented out so something is alive.

If I wanted to use this yeast, which I probably don't, what would be your
suggestions as for how to build up a healthy crop of yeast for pitching?
I'm not yet at the plating and culturing stage, and I realize that this would
be a good method, but what else can I do?

I realize this is probably not anything you'd recommend to the public, but
I'd like to know if in desperate times that there's something you can do to
save very old yeast.

Thanks,
Stuart Grant.
Hobart, Tasmania, Australia.



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