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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  RE: yeast dormant 2 years .. now working again ("David Houseman")
  metastability (Robin Griller)
  Re Regulator and OPD's (Aaron Gates)
  Re: more on hop tea (Jeff Renner)
  link of the week - Saint Patrick (Bob Devine)
  alpha and beta amylase activity temperature dependence ("Fredrik")
  RE: yeast dormant 2 years .. now working again (Bob Hall)
  Hop Oils (James Kerfoot)
  Rescue a lager ("Tom & Dana Karnowski")


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Date: Sat, 13 Mar 2004 13:34:21 -0500
From: "David Houseman" <david.houseman at verizon.net>
Subject: RE: yeast dormant 2 years .. now working again

Ryan,

I haven't revived a starter after that long but I have used packages of
Wyeast that are 5 to 6 years old and kept refrigerated.  There may be only a
few cells left alive but with a little care in a small starter I do get them
going.  Also, when I use Wyeast or Yeast Labs yeasts, I do make starters.
Doing so doesn't require the entire package so I will same some in sterile,
sealable (capped) test tubes.  I've started these after several years as
well.  Just a few mils of wort to start and keep doubling.

Dave Houseman





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Date: Sat, 13 Mar 2004 13:54:02 -0500
From: Robin Griller <rgriller at chass.utoronto.ca>
Subject: metastability

HI all,

I think Steve and I mean something different by stable. Steve's looking
for metastability, by which I presume he means permanent unchanging
stability, which I would say cannot exist when we are talking about living
organisms subject to competition, mutation and all the darwinian stuff
that goes with them. Needless to say, that wasn't my term or aim!

Indeed I do think that the Bateman's example is one that is reasonably
stable; certainly stable enough that, if it could be reproduced at home it
would be more than stable enough for us. Given that few of us repitch more
than a few times, being stable over sixteen brews would be pretty darned
stable. If we have a source of two yeasts that can stay stable over
four or five brews, we can just go back to the originals after that
right? That being said, I agree with Steve that Bateman's probably
has much more control over their brewing process than we have over ours.
Still, it might mean that our stability is over fewer, but still
sufficient numbers of batches to be worthwhile. We'll only find out
through practice, actually doing it. I do know that some
homebrewers in Britain have used Bateman's yeast (breweries over there are
often quite happy to share their yeast with homebrewers), so perhaps we
could get a comment or two from someone who has used it as to stability.

The Highgate example is, I think, quite real, rather than advertising. In
particular, there is a vanilla character to their mild that disappeared in
the test batches they did as I recall. Now I'll have to go try to dig up
the source....

It seems to me that given that homebrewers don't need to be repitching
endless times with the same culture, any more than commercial breweries
do, we could, just like commercial breweries once did, find out what
happens by brewing and seeing. The breweries that have/had multi-strain
yeasts did often apparently achieve stability over time without knowing
what they were doing in a scientific sense, but knowing what they were
doing in a practical (i.e. practice) sense--that is they had a multistrain
yeast develop into the house strain over time, producing relative
stability eventually--, so we have some distinct advantages over them. We
could for example experiment with blending the Thames Valley yeasts from
Wyeast, which are supposed to be used together commercially if the tales
are true. Not a bad place to start. I'm game to give it a go if I ever get
the chance to brew more than once every two or three months again...

Personally, I'm not sure that the idea of fermenting separately and then
blending, an admirable and worthwhile experiment in itself, would produce
the same results as fermenting together. There's a difference in what gets
fermented by which yeast when, etc., in a single ferment than in two
separate ferments, isn't there?

Robin




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Date: Sat, 13 Mar 2004 10:56:24 -0800 (PST)
From: Aaron Gates <aaronlgates at yahoo.com>
Subject: Re Regulator and OPD's

That OPD deal COULD BE AN ISSUE Alexander.... I will
check it out as I just bought that tank a few weeks
ago and noticed the Overflow Protection Device.... I
will give this a try this weekend(I work 6 day weeks)
and will issue a report on any failures/successes on
all attempts to get that flow back. It used to be so
loud that the neighbors would look over the fence.....
sounded like a jet engine... no more!

Thanks,

Aaron



Date: Fri, 12 Mar 2004 13:26:54 -0500
From: "Alexander Pettit" <hippahoratio at hotmail.com>
Subject: RE: Gas Regulator

Some folks have suggested a cleaning regimen to
resolve the issue - 
good 
idea.  Here's one other thing to look at:  If you are
working with a 
newer 
propane tank with the overfill protection valve, do
you usually 
disconnect 
your tank from the regulator between uses or leave it
connected?  If 
you 
leave it connected you may have a similar issue to one
I had with my 
gas 
grill.  I was cooking on the grill and after a while
realized that it 
was 
not as hot as it should be and found that the gas flow
appeared to be 
very 
restricted uniformly across all burners.  Was I out of
gas?  Nope.  I 
shut 
everything down, disconnected the regulator, and
waited a few minutes.  
Hooked everything back up and I was good to go.  I
don't remember the 
reasoning behind it all, nor why this sometimes
happens with tanks that 
have 
OPD valves, but I can see sense to it.




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Date: Sat, 13 Mar 2004 14:39:29 -0500
From: Jeff Renner <jeffrenner at comcast.net>
Subject: Re: more on hop tea

In the last HBD I asked about iso-hop extract.  Thanks to Michael 
Owings and Guy of Los Gatos, CA for each suggesting HopTech 
https://hoptech.com/index2.html.  It looks good for what I want:

"This extract contains pure iso-alpha acids, which can be added to 
beer at any stage (post fermentation is best) to add up to 50% of its 
bitterness. (Not recommended for bittering your beer entirely since 
there are secondary benefits from wort boiling with hops.) However, 
our Iso-Alpha extract is useful for correcting an under-bittered beer 
and also for training yourself to judge bitterness levels. In the 
book Using Hops (see page 26) a method is presented where you can use 
the Iso-Alpha extract to estimate the bitterness level of your beer 
at home. The Iso-Alpha extract can be added at any stage of brewing, 
but best utilization will occur if added just prior to bottling or to 
the serving   keg. Simply add 1/8th of a teaspoon to 5 gallons of 
beer for each single IBU you want.  Supplied in a 2 oz bottle with a 
dispensing cap, enough to add 16 IBUs to 30 gallons of beer. ISOAA 
$5.95"

Jeff
- -- 
Jeff Renner in Ann Arbor, Michigan USA, JeffRenner at comcast.net
"One never knows, do one?"  Fats Waller, American Musician, 1904-1943


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Date: Sat, 13 Mar 2004 22:20:26 -0700
From: Bob Devine <bob.devine at worldnet.att.net>
Subject: link of the week - Saint Patrick

Saint Patrick's day is this week on Wednesday, March 17th, the
anniversary of his death in 461.  Born in England, he was enslaved
in Ireland for several years.  After escaping and later becoming a bishop,
he returned to Ireland to convert the people to Catholicism.

Which of course is why folks in North American drink green beer!

Today's Saint Patrick celebrations have as much to do with true
religous or historical events as does Mardi Gras in New Orleans.
Dying things green somehow got associated with this holiday
even including dying the Chicago River green!.

So instead of a recipe for green beer, here's an article that purports
to tell of a secret ingrediant in Guinness (it might be something other
than the oft-discussed aspect of sourness or brett):
 
http://www.reuters.co.uk/newsPackageArticle.jhtml?
type=topNews&storyID=466884&section=news

Bob Devine
still in Santa Fe for a couple more weeks...


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Date: Sun, 14 Mar 2004 11:25:33 +0100
From: "Fredrik" <carlsbergerensis at hotmail.com>
Subject: alpha and beta amylase activity temperature dependence

Hello,

(2nd attempt. got complaints on non-ascii characters? strange)

I am trying to optimize my AG methods, so far I've done PG.

 I was curious if anyone has any info, graphs or something just to estimate
 the general form of the amylases temperature dependence.

 I know Steve Alexander wrote very nice posts long time ago about enzyme
kinetics talking about the first order kinetics of destruction of enzymes as
well as the kinetics in starch breakdown. But there would also be a
temperature dependance as to their optimum catalytic activity that is needed
for a full modelling. I haven't found any info on this.

I wonder what kind of mathematical shape one could assume around the peak
optimum?

Would some standard distribution like for example

Activity(T) = Peak_activity * exp( -k * (T-T_opt)*(T-T_opt) ) be a fair
assumption?

 where T_opt = optimum temp

 I was hoping someone has a link to some table or graph over amylase
activities vs temperature. Then I could
extrapolate do the an estimate.

Any info is appreciated.

  /Fredrik


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Date: Sun, 14 Mar 2004 10:31:21 -0500
From: Bob Hall <rallenhall at henry-net.com>
Subject: RE: yeast dormant 2 years .. now working again

Ryan Furstenau commented on reviving two year old yeast.

While cleaning the fridge this winter I came across a smack pack of Wyeast 
1007 that had been given to me by a local brew shop after it had expired. 
That was some time ago, as the expiration date was 9/01. I smacked it and 
let it lay on the counter for a week or so. No activity, so I tossed it in 
the trash. A week or so later I emptied the trash and found this balloon of 
a swollen pack in the bottom of the trash can. I didn't have the nerve to 
use it, but there obviously enough viable yeasties (and/or other critters) 
to munch on the nutrient solution several years after expiration.

Bob Hall
Napoleon, OH




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Date: Sun, 14 Mar 2004 10:28:30 -0600
From: James Kerfoot <jkerfoot at pressenter.com>
Subject: Hop Oils

Grape and Granary lists 4  flavor and one isomerized hop oils in their 
2003 catalog. Might be what Jeff and Domenick were referring to?



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Date: Sun, 14 Mar 2004 21:23:24 -0500
From: "Tom & Dana Karnowski" <karnowsk at esper.com>
Subject: Rescue a lager

I put a couple of fermenters in the cold-storage unit yesterday for
long-term lagering.  But I took them out when I realized I was cooling them
too fast.  They went from about 60 F (diacetyl rest) to 40F in the course of
a single day.  So I took them out and I am letting them sit at about 60F for
a few days.  Then I'm going to cool them maybe 5 degrees/day down to 40 F as
Al Korzonas suggests in "Homebrewing Vol. I".

I would like feedback on this rescue effort.  I think the fear of cooling
too fast is that it will shock the yeast, but does anyone think my rescue
will work?  Should I pitch fresh yeast too?  How can I tell if the yeast is
still working or not?

I used White Labs 830 and it was kind of sulfuric during the starter stage
but I figured that was a characteristic of the yeast and time will remove
it.

thanks!
Tom Karnowski
Knoxville TN



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