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HOMEBREW Digest #5504
HOMEBREW Digest #5504 Sun 15 February 2009
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Re: Low Alcohol Big Beers ("Greg 'groggy' Lehey")
HBD Server Fund (Fred L Johnson)
O2 Saturation ("A.J deLange")
FW: Yeast Performance / Aerobic propagation (Joshua Wilkins)
re: Low Alcohol Big Beers (steve alexander)
Re: aerobic growth is not respiration (Fred L Johnson)
2009 Charles Town Homebrew Competition ("H. Dowda")
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Date: Sat, 14 Feb 2009 17:07:55 +1100
From: "Greg 'groggy' Lehey" <grog at lemis.com>
Subject: Re: Low Alcohol Big Beers
On Friday, 13 February 2009 at 8:32:54 -0600, Eric (Rick) Theiner wrote:
> Hail Brewmeisters,
>
> My preferred brews are big on flavor, body, hops, etc.
> Thus I often brew IPA's and similar, but I would really
> rather not have to deal with the typically accompanying
> high level of ethanol. If I sit down for 3 or 4 over the
> course of a few hours, I'd rather not be intoxicated at the
> end of the evening.
I know the feeling.
> I have been thinking about playing around with high dextrine malts,
> but before I started down that road, I thought I'd ask if anyone on
> this list has done something along those lines...
I've been trying this way for some time. The standard malts available
here in Australia are relatively high in dextrins, but there's more to
flavour than body. I'm brewing my current beers at about 13% Brix and
then diluting 50:50 with water; the flavour is more hop-based than
malt-based. I don't think I'll win any prizes for them, but they're
comparable in body with full-strength commercial beers.
Greg
- --
Finger grog at Freebsd.org for PGP public key.
See complete headers for address and phone numbers.
------------------------------
Date: Sat, 14 Feb 2009 07:43:54 -0500
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: HBD Server Fund
Hey, guys. Note in the header of the Homebrew Digest the appeal for
us to financially support this great service. The janitors note that
if we all gave a very small amount annually, the HBD can continue
with financial ease. Otherwise, they deal with an endless struggle to
keep the service running.
Fred L Johnson
Apex, North Carolina, USA
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Date: Sat, 14 Feb 2009 08:56:25 -0500
From: "A.J deLange" <ajdel at cox.net>
Subject: O2 Saturation
For Bill Kaiser: When you say "saturation" WRT O2 measurement that
usually means WRT to air i.e. most DO meters will read 100% at about 8
mg/L at reasonably cool temperature. When oxygenating with pure O2,
however, saturation means about 5 times this. When I used to oxygenate
after the wort was in the fermenter (I now do it inline - as the wort
enters the fermenter) I found it would take about 3 minutes to pin my
meter which reads up to 20 mg/L (about twice air saturation and 2/5
pure O2 saturation) using a small(1 1/2 inch x 3/8 inch dia?) sintered
stainless steel stone at a flow rate just sufficient to cause bubbles
to appear at the surface. This I have always found to be sufficient.
Obviously it's going to depend on the flow rate and the size of the
bubbles somewhat. Be sure to move the stone around in the solution.
As I recall the molecular sieves produce about 95% pure O2 so the
results you get should be very similar to what you would get from
bottled O2.
A.J.
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Date: Sat, 14 Feb 2009 16:17:33 +0000
From: Joshua Wilkins <jowilki3 at hotmail.com>
Subject: FW: Yeast Performance / Aerobic propagation
Hey guys,
I am very busy this weekend, so give me some time to respond back on Mon to
some of the more specific things asked about my post.But I'll answer some now.
"Do you have any ballpark recommendations on how long it would take to
attain 100% saturation using a surplus medical O2 concentrator and an
aquarium airstone? (that I just happen to have)"
Yes, in my industry it is fairly standard to set the run parameters for at
least 45- 60 minutes, although longer is better, before saturation is
accomplished.We then calibrate DO probes to 100% saturation. Speaking
of which since I know some of you have DO probes, be careful how you use
them because they depend highly on how they are calibrated and maintained.
Once calibrated to 100% saturation and zero % saturation, they need to remain
within that media or else they need to be recalibrated to be accurate.
Also the biggest problem with DO probes is that the probe itself needs to
be replaced frequently when used in anything other than water. The media
fouls up the membranes giving rise to inaccurate readings. In my industry
we replace them every third batch, but I have seen in labs using them longer.
But consult your literature on your specific models.
Fred I cannot speak for white labs nor wyeast as I am not affiliated nor have
I seen their facilities. But they are confined within another specific industry
with particular goals (high biomass, sterility, cost, and shipping methods are
probably their biggest issues), so using their methods for brewing should not
be done. But knowing why they do things can help you in brewing. I would
assume they are using aerobic growth for the high biomass yields. But I'll
touch more specifically on your questions on Mon in a separate posting so
I can get into some details.
Matt you are correct that there is a lot of science terminology that gets used
slightly incorrectly as shorthand in industry,so I apologize for the confusion.
But I do have one correction to your statement, respiration more specifically
speaks of the glycolytic pathway which is present in both aerobic and anaerobic
growth phases (including alcoholic fermentation). In alcoholic fermentation
respiration begins with glucose and ends with pyruvate before it gets shuttled
into the actual alcoholic formation or diacytyl pathway.
Also there is a lot of referencing to the Crabtree effect, of which I am also
going to save for my post on Mon because I always confuse it with the pasteur
effect and catabolic repression when going from memory, so I want to go back
to their definitions, but from memory it does not play as critical a role as
you all make it sound. These three are very important effects to know of for
troubleshooting,but they are not as common as you may think. They DO NOT
define or govern a fermentation process, but they do occur in it.
Happy Valentines Day..
Josh Wilkins
------------------------------
Date: Sat, 14 Feb 2009 13:58:24 -0500
From: steve alexander <steve-alexander at roadrunner.com>
Subject: re: Low Alcohol Big Beers
Rick Theiner mentions,
> My preferred brews are big on flavor, body, hops, etc.
> Thus I often brew IPA's and similar, but I would really
> rather not have to deal with the typically accompanying
> high level of ethanol. If I sit down for 3 or 4 over the
> course of a few hours, I'd rather not be intoxicated at the
> end of the evening.
>
> I have been thinking about playing around with high dextrine
> malts, but before I started down that road, I thought I'd ask
> if anyone on this list has done something along those lines...
>
> And if not, what are your general thoughts on getting to my
> goal of a really big, but low alcohol beer?
>
> Rick Theiner
>
Rick - our preferences have a lot of overlap. I really like flavorful
interesting beers, but for everyday drinking the 15P+ monster beers aren't
a good choice. OTOH alcohol definitely has an impact on body/
mouthfeel.
Perhaps I'm wrong, but my feeling is that (using conventional methods) it's
not possible to create a really big low-alc beer. Flavors like big hops
must
be balanced with big malt. To include so much malt flavor means high OG
and your only choice is to either attenuate the OG into big alc or leave the
OG as big dextrin; neither is acceptable in a session beer IMO. In my
experience if you start around 12P,with attenuation much below 72%AA
by either mashing or loading up on crystal, then you end up with one of
those syrup-y dextrinous beers [gluhbier] that isn't useful as a session
beer.
You can make a very good APA/IPA style beer (perhaps violating the
style guidelines) starting at an OG of 12P, but don't expect to include
75IBU. You'll want to make extravagant use of specialty malt, but
again - the attenuation needs to be reasonably high.
You can push the malt flavors upward by a careful choice of malt .. a
good toasty UKpale malt, or melanoidin or munich malt perhaps, some
wheat then match malt flavors w/ hops. Still, you have a fundamental
limitation; you can only hop to match the malt flavor, the malt flavor is
limited by the OG, and the OG results in either alcohol or dextrin -
checkmate !
It's no wonder that many traditional session beers start like at 7.5-10P,
since w/ modest alc and modest dextrin you can drink many of these
and they still taste good.
-S
------------------------------
Date: Sat, 14 Feb 2009 14:06:35 -0500
From: Fred L Johnson <FLJohnson52 at nc.rr.com>
Subject: Re: aerobic growth is not respiration
Matt points out that we should simply refer to respiration versus
fermentation in the discussion of yeast propagation, with respiration
being aerobic whereas fermentation can be aerobic or anaerobic. I
would probably generally agree with this except that many folks use
the phrase "anaerobic respiration" as being equivalent to
"fermentation". To avoid confusion, I will try to use the phrase
"aerobic respiration" to clearly distinguish purely oxidative
production of carbon dioxide and water from the process that yields
carbon dioxide and ethanol.
To reiterate, the production of ethanol is the hallmark of
fermentation. The goal of yeast propagation with very low
concentrations of sugars in the medium in the presence of oxygen is
to convert as much of the energy contained within those sugars into
cell mass rather than to lose it in the mass of ethanol.
Fred L Johnson
Apex, North Carolina, USA
------------------------------
Date: Sat, 14 Feb 2009 19:49:06 -0800 (PST)
From: "H. Dowda" <hdowda at yahoo.com>
Subject: 2009 Charles Town Homebrew Competition
Entries for the first AHA sanctioned Charles
Town Homebrew Competition are being taken.
Entries and paperwork must be in Charleston
S.C by Feb 28. BJCP judges are especially
invited. Enter and help us get homebrewing
competitions going strong in the S.C.
Lowcountry.
Visit:
www.lowcountrylibations.com for complete
info
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End of HOMEBREW Digest #5504, 02/15/09
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