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HOMEBREW Digest #4934
HOMEBREW Digest #4934 Sun 22 January 2006
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Re: You know it's been a while since you've brewed when... (Ben Hanson)
Re. Increasing IBUs ("William Frazier")
Low Alcohol output ("Tricia Simo Kush")
Commercial beer suggestions ("GRANT STOTT")
Aroma Hops and Bitterness (David Edge)
re: converting a keg to a secondary fermenter ("C.D. Pritchard")
yeasts attenuation/flocculation/storage ("steve.alexander")
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Date: Sat, 21 Jan 2006 09:43:11 -0500
From: Ben Hanson <benhanson at verizon.net>
Subject: Re: You know it's been a while since you've brewed when...
You know you haven't brewed for a while when...
you have a carboy of mead on the counter you made the year your 5 year
old was born which has been clear and waiting to be bottled for the last
18 months........and it's the last thing you brewed. (Should be good
though - made from my own bees' honey!)
Ben
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Date: Sat, 21 Jan 2006 10:18:45 -0600
From: "William Frazier" <billfrazier at worldnet.att.net>
Subject: Re. Increasing IBUs
Russ - Consider a hop extract. Go to www.hoptech.com. They have some
extracts that can be used just for bitterness. I have some but have not
needed to use them yet.
Bill Frazier
Olathe, Kansas USA
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Date: Sat, 21 Jan 2006 16:58:46 -0600 (CST)
From: "Tricia Simo Kush" <mpls at realmofzorcon.com>
Subject: Low Alcohol output
Hello all - first time poster, been reading for roughly a year (thanks to
Joe M. in Seattle). I'm in Minneapolis and my husband and I have
homebrewed for roughly ten years.
We have a VERY basic setup and, for the most part, make some darn fine
beer. Our most frequent struggles are with either low carbonation or low
alcohol. The former issue we can work around with a hand-tap on the keg
(CO2 has been a significant problem in the past, so let's not go there).
The alcohol issue hasn't reared it's, uh, head in a while, but we were bit
by it with our most recent batch.
I can provide specific batch details, but I was hoping that the trick
might be something more general, since it almost seems random in
occurance. Our other batches of beer are nearly TOO high in alcohol (as
in "our friends sleep over when we unveil a new batch"), so we are
stumped.
Here are a few details:
We have switched to liquid yeast - no more dry.
Here is the kit we usually make, with VERY wonderful and nearly
predictable results:
http://www.midwestsupplies.com/products/ProdByID.aspx?ProdID=3494
Here is another kit we enjoy and ALSO yields great results:
http://www.midwestsupplies.com/products/ProdByID.aspx?ProdID=3317
(Yes, the kits show dry yeast - we ALWAYS upgrade.)
This batch, however, came in so low that we call it "beer-flavored water".
It tastes great but has no *zing*.
http://www.midwestsupplies.com/products/ProdByID.aspx?ProdID=3554
Again, I don't want to toss out a lot of details unless the evidence
suggests something more specific. Is a lackluster alcohol something that
we should expect to see from time to time, or is there an obvious and
reasonable cause for this?
The newsletter has been terrific and the community is rich, so I am
hopeful for some good suggestions!!
~ Trish K.
------------------------------
Date: Sun, 22 Jan 2006 17:14:16 +1100
From: "GRANT STOTT" <gstott at iprimus.com.au>
Subject: Commercial beer suggestions
3rd attempt to post after upgrading my computer. Have configured outlook
according to the website suggestions so should work this time.
A friend who is going to Portland Oregon in a few weeks time has offered
to bring back a small selection of beers. The only beer I have tried
from this area is Bridgeport IPA, which we both like. As only one decent
American beer is available over here Sam Adams boston Lager. I don't
think I will be offending anyone (If so I appologise as we are all
entitled to our own taste) in saying otherwise we can only get Bud,
Miller, Coors.
What I would like are suggestions of good brews that are easily
available in this area to put on a short list to bring back & try, & the
ones we like best we will most likely try to brew in the future.
Offline replies are most welcome. Send to gstottATiprimusDOTcomDOTau
(should be obvious)
Thanks,
Grant Stott
Geelong Vic
Australia (where if reached 105`F today)
------------------------------
Date: Sun, 22 Jan 2006 14:27:55 +0000
From: David Edge <david.j.edge at ntlworld.com>
Subject: Aroma Hops and Bitterness
Fred Johnson observed that some commercial micros
have a single late addition. In the UK some certainly
put a very small amount in early and 90% late. York
Brewery for example makes very bitter beers this way.
As Fred observes, the hops are sitting in hot wort for the
hour or so it takes them to pump through the paraflow in
their (I think) 20 UK brl plant. A big vessel will cool a lot
less that a small homebrew kettle in that time.
Immersion coolers are different - they cool the whole wort so
isomerisation will be negligible after a couple of minutes
- my wort comes down to 70 degC / 160degF very quickly.
I spent ages the other day searching my notes from courses
at Brewlab (Sunderland, UK) for a graph that showed
bitterness extraction for kettle off hops. I can't find it
but I seem to recall it could reach 80% compared to full boil,
but I'll chase that up.
We used to have a convention that hops added at 0 minutes
were entered into Promash as 10 minutes if they steeped for
some time. (We never add hops at 10.) It was just a guess.
David Edge, Derby, UK
------------------------------
Date: Sat, 21 Jan 2006 10:45:43
From: "C.D. Pritchard" <cdp at chattanooga.net>
Subject: re: converting a keg to a secondary fermenter
James Payne asked about converting a pin lock corny keg to a secondary
fermenter.
Cornies make great secondaries. I like them because you can pressurize
them with CO2 to aid in transferring the brew.
Not much in the way of modifications are need for use as a secondary. Just
fit an airlock onto the gas disconnect or run vinyl tubing from the
disconnect to a jar of sanitizer. Depending on how clear your brew is
going into the secondary, you might want to cut off the liquid dip tube a
bit to avoid sucking up dregs in the bottom of the keg. Better still,
attach a flow diverter from a plastic racking cane to the end of the dip
tube. Since the ID of the diverter is larger than the OD of the dip tube,
I use a spacer cut from a bit of vinyl tubing to get a good fit.
A cornie can also be used as a primary fermenter if you fit it with a large
diameter blow-off. Details on how I do this are at
http://chattanooga.net/~cdp/kegferm/kegferm.htm
c.d. pritchard cdp at chattanooga.net
http://chattanooga.net/~cdp/
------------------------------
Date: Sun, 22 Jan 2006 15:44:03 -0500
From: "steve.alexander" <-s at adelphia.net>
Subject: yeasts attenuation/flocculation/storage
Randy Ricchi and Fred Johnson bring up some good points ...
One of the least well explained characterization parameter for yeast is
"attenuation potential".
The basic idea is that you drop some amount of the yeast into
a closed fermenter of controlled media and observe the attenuation.
There are SOME few brewing yeasts that will not handle significant
sugars ... an Aussie paper a few years ago had an ale yeast that
ignored sucrose for example. Despite this nearly all brewing yeasts
have the genetic hardware needed to get "full" attenuation of wort.
The difference between yeast is not the basic fermentation capability,
but the expression of that potential.
For various reasons the "less attenuative" yeasts stop growing and
then typically flocculate before other yeasts. Flocculated yeast
still ferment, but at a very low rate, and they do not rapidly attenuate
wort.
==
Flocculation is a pretty straightforward topic.
/Yeast given 'growth condition' do not flocculate.
/If growth conditions do not obtain, then yeast with the genetic
capability become POTENTIALLY flocculant. This causes
dramatic changes to the cell surface.
/ Potentially flocculant yeast actually flocculate if certain
environment conditions exist related to the flocculation genetics.
[divalent ions like Ca++, low ethanol levels, pH ...]. Flocculation
conditions almost always appear in normal beer.
Corollary: / If growth conditions are restored to flocculated yeast,
they de-flocculate.
Note: There are non-flocculant wild yeast and these yeasts
will also cease attenuating once growth conditions are removed.
==
Lack of growth conditions causes (potential) flocculation and
additionally causes stalled attenuation. Don't confuse flocculation
with a cause of incomplete attenuation. That's like blaming
brown leaves for the cool weather of Autumn.
An early flocculating yeast is also one with more stringent growth
requirements. Despite this many studies have shown that
carefully lab conditions can achieve ABV% in the mid-teens and
even over 20% with common brewing yeasts. The reason
that barleywines are difficult to ferment is primarily in the
poor growth conditions NOT fundamentally the yeast. Of course
choosing a yeast with less stringent growth requirements makes it
that much easier to get full attenuation.
It's been know for a long time that different yeasts have different
oxygen requirements - some can ferment normal wort cycle
after cycle with 8ppm of O2, while some varieties need 24+ppm.
If you examine the yeasts it appears to me that the hi-O2-req yeasts
are all ale yeasts and often low-attenuating top fermenters. Perhaps
these yeast can't use both O2 atoms when making lipids or perhaps
these have lower maximum lipid content. In any case lack of oxygen
req lipids (sterols & UFAs) is a very common reason for lack of
growth and probably the leading cause of incomplete attenuation.
The other thing that's not clear to the average brewer - yeast have to
pump ions in&out of their surface membranes across a very considerable
osmotic pressure gradients. The osmotic pressure is related to the molar
concentration and most of the molar concentration in wort comes from
fermentable sugars (abt 2/3rd of extract is fermentable, but this is well
over 2/3rds of the non-water molecules). The story gets MUCH worse
as fermentation progresses. every glucose is converted to 2 ethanols,
every maltose to 4 ethanols, and the maltotriose to 6 ethanol molecules.
Fermentation progress cause a rapid and radical increase in osmotic
pressure, and at the same time the cell membranes become dramatically
weaker as the original sterol&UFA is spread out among 4 to 10 times
more cells. The weaker membranes permit more ion leakage and so
more work for the cells. Of course hi-grav brewing is the worst case
scenario,
The rule of thumb that you should pitch yeast in proportion to the OG
is the right direction but doesn't go far enough. If you usually
use X amount of yeast in a 5gal, 12P wort and you double the pitching
rate for 5gal of 24P wort you still fall short of the mark. In the second
case the strong 24P wort holds LESS O2 than the 12P stuff, and it's
divided among twice as many cells. By the time the fermentation is
finished the 24P wort will have twice the osmotic pressure as the 12P
so the yeast will be under far more stress.
I 'm not a hi-grav beer fan, but if you are then plan on pitching far
more yeast and consider pitching well aerated starters several times
throughout the fermentation. I'd also suggest that some of the less finicky
yeasts like WY1028 would be a better choice than WY1084 for the
hi-grav range.
High CO2 levels also slows growth. Limited FAN, perhaps especially
in high grav heavily pitched wort is a likely source of growth limitations.
===
It was odd to read FredJ's comments about storing stalled starter yeast
under beer in fridge. After years of carrying far too many yeasts around
on frozen plates I have honed in on the same method. I just pulled an
ale yeast back (easily) after a year under beer in the fridge. I have a
modest library under beer in whitelab type tubes. I would never
suggest pitching these directly, but it seems to be adequate for culture
storage. I wonder how well it would work with some of the more
delicate yeasts.
>Is there anything likely to be wrong with the yeast stored and
>revived in this manner? Petite mutants? Selection of
>subpopulation?
Probably not petites assuming you do a build-up but we are
selecting a subpopulation that can survive the selection & cold
storage. That *might* correlate with things like more storage
carbos or better membrane integrity. One might speculate that
this might advantage early flocculation lower attenuation,
but it's only speculation.
-S
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End of HOMEBREW Digest #4934, 01/22/06
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