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Date: 22 Jun 2006 23:00:01
From: Request Address Only - No Articles
Subject: Homebrew Digest #5025 (June 22, 2006)
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HOMEBREW Digest #5025 Thu 22 June 2006
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
re: Best pitched when? ("steve.alexander")
re:open fermentation ("Ben Dooley")
shout out to Wisconsin brewers! (Joe Katchever)
Re: ("Upgrading Q. Februarys")
Asalamalekum! .........URGENT REPLY ... (USMAN WADE)
re: Best pitched when? (Kevin Elsken)
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----------------------------------------------------------------------
Date: Wed, 21 Jun 2006 03:06:13 -0400
From: "steve.alexander" <-s at adelphia.net >
Subject: re: Best pitched when?
Kevin Elsken of the 'burgh asks,
<<
when is a starter at optimum? [...] - is it best to let the
starter completely ferment out and pitch the slurry? Or is there a more
optimum point in the cycle to pitch? [...]
>>
That depends on which parameter you are trying to 'optimize'.
The general rule is that we want the yeast to take off readily
after the wort is cooled. The primary reason for this is to prevent
infection, that is unwanted molds and bacteria from getting an early
foothold. Of course there are many other goals one could consider.
You must realize that during a normal fermentation the yeast
metabolism undergoes numerous shifts. If you pitch 'dormant'
yeast from an anaerobic starter which has finished, the yeast
begin to uptake oxygen and use internal carbo stores (ignoring
the wort sugars for a while). Then they shift to take in the
mono-saccharides via a passive transport mechanism, then the
di- & tri- sacch's via a facilitated transport mechanism. As
yeast growth trails off the yeast stop producing fatty acids and
instead produce AAT enzymes which mop up the fatty residues and
also produce esters. Early when the wort amino acids are
plentiful, some may be used for energy, but late in the
fermentation when the aminos are low the yeast must
synthesize required aminos from the few types remaining of
from inorganic amine groups. Either produces additional fusels.
Of course very late in the fermentation, brewing yeast undergo
rather extensive changes to the cell surface which cause
flocculation - later when repitched the cell surfaces must be
restored to their non-flocculent state.
So all throughout fermentation the yeast metabolism is shifting
and these shifts involve regulated changes to genetic expression,
and typically the production of enzymes to catalyze the
processes, and also as part of regulation. So the shifts cost
time and energy. It might take 2o-60 minutes for healthy,
energetically sound yeast to shift from glucose only environment
to maltose induction. Probably much longer for compromised yeast.
At the completion of a normal brewery ferment the yeast are not
in ideal condition. They've been O2 deprived, the osmotic pressure
from ethanol & the CO2 pH related inhibition have been taking up
valuable energy, and many amino acids have been missing for some
time. In a starter you *can* do much better by using low gravity
wort 8-10P, continuous aeration as on a stir plate, and even a little
yeast nutrient. Of course you can also make starters which are more
like mini-brewery ferments.
So if you are making top-notch starters as above, then I'd suggest
that should ideally pitch before the yeast flocculate, but this can be
quite late in the starter ferment - say 60+% apparent attenuation.
If your starters are more like brewery ferments, not continuously
aerated, normal grav, etc, then I'd suggest you pitch the starter
when the starter is about half-way through the ferment - say 35-40%
apparent attenuation. You can slow down the starter by placing it
in a fridge and thus control the timing.
This evaluation is most useful at the utopian brewery. The reality is
that if you are making a 15P dark monster bock, and your starter is
made from well aerated 8P pale wort, that you *will* want to separate
out the aerated-stale, thin, pale starter wort and toss it. Unless
you have access to a centrifuge that will take a few liters you'll
have to chill separate the yeast or let the fermenter finish and
flocculate. The choice to invest in a $15k centrifuge or accept
healthy but flocculated yeast which may cause a minor fermentation
delay should be obvious to the HBers.
Anyway it is a useful gedankenexperiment. The point to keep in
mind is that you must always be aware of whether you are trying to
make optimal beer or optimal yeast in a given ferment. The two goals
are at odds with each other !!
-S
/**/
------------------------------
Date: Wed, 21 Jun 2006 11:01:09 -0400
From: "Ben Dooley" <bendooley at gmail.com >
Subject: re:open fermentation
Thanks for the advice. I checked the beer out last night, and the
krausen is high. Is this the best time to harvest yeast? I thought I'd
skim some off and stick it in the fridge to use for the next batch.
Thanks again for the help.
Best,
Ben
------------------------------
Date: Wed, 21 Jun 2006 11:39:33 -0500
From: Joe Katchever <joe at pearlstreetbrewery.com >
Subject: shout out to Wisconsin brewers!
I'd like to get in contact with the homebrewers in the area. I live in
La Crosse, Wisconsin; on the bank of the mighty Mississippi. Any nearby
Minnesota homebrewers give me a shout, too. I'd like to organize a
homebrew club. I know there are several homebrewers in the area, but no
one seems to know one another. email me at joe at pearlstreetbrewery dot
com.
Egor the Orange
------------------------------
Date: Thu, 22 Jun 2006 04:49:35 -0700
From: "Upgrading Q. Februarys" <msk at goooo.3322.org >
Subject: Re:
welco me to the best pharmacy http://milesesto.com/?IJESRKQV1AQHVZUFcaWkNV
------------------------------
Date: Thu, 22 Jun 2006 05:10:53 -0700 (PDT)
From: USMAN WADE <usmanwade_4 at yahoo.com >
Subject: Asalamalekum! .........URGENT REPLY ...
Hello ,
I would like to apply through this medium for your
co-operation and to secure an opportunity to invest
with you in your country with my inheritance .My name
is Mr Usman Wade 27 years old single never marry from
Swaziland presently living in Dakar Senegal under (UN)
United Nation.
I have a substantial capital Nine million american
dollars i honourably intend to invest in your country
into a very lucrative business venture of which you
are to advise and execute the said venture over there
for the mutual benefits of both of us , this money was
made by my late beloved father through Diamond Export
and he deposited it in fiduciary company here in Dakar
Senegal under my name as the next of Kin. all the
document that covering this fund is with me here , i
have meet the fiduciary company on my arrival here and
the fund has approve to relies to me that is why i
contact you so that i can live with you and invest
with this money under you proper manage and care.
I dont want to live here in Africa because of War here
and there every day that is why i contact you because
i want to live the rest of my life in your country and
invest with this money.
What i need is your ideas on how this money will be
invested,properly managed and the type of investment
the money will invest in your position because this
money is my only hope to start a new life.
Looking forward to your response.
Yours Faithfully,
Mr Usman Wade.
__________________________________________________
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------------------------------
Date: Thu, 22 Jun 2006 22:32:45 -0400
From: Kevin Elsken <littleboybrew at verizon.net >
Subject: re: Best pitched when?
Steve, as always thank you for the informative reply.
My normal mode of operation is to use dormant yeast. I have been in the
habit of making starters in the 8-10 P range (I have read your
recommendations before), but I do not have a stir plate or method of
feeding oxygen.
Suppose I had I liter or starter that had fermented out and
flocculated. If I drained off the spent wort starter and added, I don't
know, say 500 ml of fresh pre boil wort to the slurry, that would give the
yeast maybe 2 hours to wake up prior to pitching into the fully finished
beer (by the time I run off all the wort and boil and cool). Would that be
enough time to make a difference, or would I be better off to make 500 ml
of fresh starter say 24 to 48 hours before brewing and pitch the slurry
into that?
Kevin
------------------------------
End of HOMEBREW Digest #5025, 06/22/06
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Date: 23 Jun 2006 03:14:56
From: John 'Shaggy' Kolesar
Subject: Re: measuring and adjusting ph
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On Fri, 23 Jun 2006 02:44:02 GMT, <.@. > wrote:
>> Lets say that the buffering (kH) of your water is initially too low and
>> the pH will have wild swings so that the pH will be way too low when
>> added to grains.
>
>>OK, I can buy that a chemical can be added that will
>> increase the buffering to the point where the water pH will stabilize in
>> the correct range when added to grain.
>
> The 'buffering agent' that you are adding will increase (if your initial pH
> is low) or decrease (if your initial pH is high) your water pH to the target
> 'buffer pH'. The buffer will have limitations that are a property the
> buffering capacity. The more buffer that is added, the greater the
> buffering capacity. The buffering capacity is the amount of acid or base
> that the buffer can 'consume' and still maintain pH. As you increase the
> concentration of the buffering components, you increase the buffering
> capacity.
Absolutely, which is what needs to be done if the initial buffering
capacity of your water is too low. That's not the only problem you
can have with water though.
>>Now lets assume that you have the
>> opposite problem and the buffering of your water is way too high which
>> means that it takes a lot more acid to alter the actual pH, IE the mash
>> will end up with too high of a pH.
>
> Your tap water will most likely not be buffered at any pH. It will simply
> have a low or high or 'in range' pH.
Tap water will normally have a pH that is too high. What I'm saying is
that if the buffering capacity of the water is already too high, then
you actually want to decrease the buffering capacity, otherwise the
acid in the grains will not be able to get the water into the correct
range. This scenario is actually the more common problem, which is why
for those people that do really have pH issues in the mash, usually it's
because the pH doesn't get low enough and they need to acidify their
mash to correct it. It's not the pH that is a problem with their water
chemistry, it's the kH.
>> In that case you need to reduce the
>> buffering of the water in order to have it end up in the correct range
>> when
>> added to grain.
>
> No. The buffering agent that you add will shift your tap water pH into the
> buffer pH (determined by the components of the buffer). This is independent
> of your starting tap water pH (with in reason, more buffering agent will
> need to be added if the pH is at high or low extreme).
No, buffering (kH) does not directly effect the pH of the water. It only
effects the amount of pH change that will occur if you put a given amount
of acid or base into the water.
Assuming that the amount of acid is fixed (IE, from the grains), then the
final pH will be determined by the amount of buffering capacity in the
water. If that capacity is too low then you need to increase it, if it's
too high then you need to reduce it. You can't do both with the same
product.
>> There is no possible way that the same chemical "5.2 stabilizer" can fix
>> both of those water conditions since they require completely opposite
>> solutions.
>
> Wrong. Low or High pH, does not matter. That is the nature of a buffer.
That's not at all what I'm saying. I understand that the pH of the
initial water does not matter, which is exactly what I've been saying
from the beginning. What *does* matter is the kH of the water which is
the buffering capacity. That is what you need to alter in order for
the grains to be able to naturally correct the pH by themselves. For
some water you will need to increase the kH, but for other water you
may need to reduce it.
>> Lets take another example and assume that the buffering of the water is
>> already good, but the pH of your tap water is 3. I realize that's a
>> little
>> silly, but their marketing slogan did claim that it could fix your water
>> problems "no matter what".
>
> It will buffer the pH 3 water into range, but it might require more
> buffering agent than if the starting pH was closer to the target pH. The
> initial buffering is added will be consumed by the extremely low pH, but as
> you add more, the pH will hit the target buffer pH (determined by the
> components of the buffer).
One of us is obviously confused.
John.
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Date: 23 Jun 2006 03:50:58
From: Stoutman
Subject: Re: measuring and adjusting ph
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Are there any OTHER chemists out there that wanna take a crack at this?
I'm not sure how else to explain it.
I can suggest only one thing here John, a kind of 'right in front of your
eyes' kind of experiment. Buy some of the 5.2 buffer. Prepare two 1-gallon
tap water containers, one that you adjust the pH to 4 and one that you
adjust to 8. Add the buffer and than measure the pH in both.
Report back to me here with your results.
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Date: 23 Jun 2006 04:15:52
From: John 'Shaggy' Kolesar
Subject: Re: measuring and adjusting ph
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On Fri, 23 Jun 2006 03:50:58 GMT, <.@. > wrote:
> Are there any OTHER chemists out there that wanna take a crack at this?
Out of curiosity I looked at some of your other posts on usenet groups
about water chemistry and have decided I'm done with this discussion. If
you want to troll somebody, then find another victim to play with.
I'll leave it up to everyone else to decide what they want to believe. Based
on your posting history, I don't see much point in responding anymore.
John.
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Date: 23 Jun 2006 04:30:58
From: Stoutman
Subject: Re: measuring and adjusting ph
|
"John 'Shaggy' Kolesar" <spam@shagg.net > wrote in message
news:slrne9mqqq.s7m.spam@weizen.shagg.net...
> On Fri, 23 Jun 2006 03:50:58 GMT, <.@.> wrote:
>> Are there any OTHER chemists out there that wanna take a crack at this?
>
> Out of curiosity I looked at some of your other posts on usenet groups
> about water chemistry and have decided I'm done with this discussion. If
> you want to troll somebody, then find another victim to play with.
>
> I'll leave it up to everyone else to decide what they want to believe.
> Based
> on your posting history, I don't see much point in responding anymore.
>
>
> John.
Ok John. I'm a Troll and you 'understand' what a buffer is.
I have read some of your posts as well. You have discussed this topic in
the past (2004) and you 'Still Do Not Understand'.
Sorry I couldnt help ya!
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Date: 23 Jun 2006 03:37:00
From: Stoutman
Subject: Re: measuring and adjusting ph
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> Tap water will normally have a pH that is too high.
Agreed.
>What I'm saying is that if the buffering capacity of the water is already
>too high,
Tap usually does NOT have any buffering capacity. Tap water is usually not
buffered at any pH. Tap water will NOT resist changes in pH when an acid or
base is added.
>then you actually want to decrease the buffering capacity, otherwise the
> acid in the grains will not be able to get the water into the correct
> range.
You will need to lower the pH. This can be achieved by using/adding a
buffer to your mash water.
> This scenario is actually the more common problem, which is why
> for those people that do really have pH issues in the mash, usually it's
> because the pH doesn't get low enough and they need to acidify their
> mash to correct it. It's not the pH that is a problem with their water
> chemistry, it's the kH.
If they are starting with water that has a high alkalinity (kH), they can
combat this by lowering the pH by adding the appropriate buffer.
>
>>> In that case you need to reduce the
>>> buffering of the water in order to have it end up in the correct range
>>> when
>>> added to grain.
No, you are not reducing the "buffering of water", you are reducing the pH.
Tap water is 'usually' NOT buffered.
>>
>> No. The buffering agent that you add will shift your tap water pH into
>> the
>> buffer pH (determined by the components of the buffer). This is
>> independent
>> of your starting tap water pH (with in reason, more buffering agent will
>> need to be added if the pH is at high or low extreme).
>
> No, buffering (kH) does not directly effect the pH of the water. It only
> effects the amount of pH change that will occur if you put a given amount
> of acid or base into the water.
Alkalinity (kH) is not the same as buffering capacity.
>
> Assuming that the amount of acid is fixed (IE, from the grains), then the
> final pH will be determined by the amount of buffering capacity in the
> water. If that capacity is too low then you need to increase it, if it's
> too high then you need to reduce it. You can't do both with the same
> product.
Wrong. A buffer will prevent sharp changes in pH in either direction.
<SNIP >
> One of us is obviously confused.
Look man, there is no conspiracy here. Please read into what a buffer
is/does.
This might help:
http://en.wikipedia.org/wiki/Buffer_solution
>
>
> John.
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