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HOMEBREW Digest #4862
HOMEBREW Digest #4862 Wed 05 October 2005
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: pbabcock at hbd.org
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Contents:
Analysis of the Continuous sparging process/Viscosity issues (David Harsh)
Re: Mashout temp and viscosity ("Peter A. Ensminger")
The Second 2nd Annual Hogtown Brew-Off (Mark Tumarkin)
racking of p-lambics (KEITH R BUSBY)
Re: And another thing ! (Jeff Renner)
Viscosity ("Spencer W. Thomas")
RE: Subject: efficiency, 1/ batch sparge analysis (Steven Parfitt)
Sparge efficiency, Mash out and CharlieP ("Dave Burley")
Re: Wort Chiller Efficiency ("Craig S. Cottingham")
RE: Wort Chiller Efficiency ("Mike Sharp")
The Second 2nd Annual Hogtown Brew-Off (Mark Tumarkin)
Steve Alexander and Steve Jones re Efficiency and Batch Sparging (Bill Velek)
Dixie Cup XXII call for judges ("rkolacny")
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Date: Wed, 5 Oct 2005 00:06:21 -0400
From: David Harsh <dharsh at fuse.net>
Subject: Analysis of the Continuous sparging process/Viscosity issues
Steve Alexander presents an interesting analysis of a continuous
sparging process, but unfortunately, he hasn't modelled the grain bed
used in any lauter tun I've ever encountered.
Look at the process as described in the model:
> "S/2 case":
> Step 1: remove S/2 of the original mash water. <snip>
> Step 2: After equilibrium, we again replace S/2 of the liquid.
> <snip>
> Drain: Finally we drain the (M+X-U) volume of liquid
What is described here is a sparge process where the grain bed is
continuously stirred in order to maintain a uniform concentration
within the entire bed; analogous to a stirred tank reactor. Since
we're dealing with a fixed bed extraction, operating in unsteady state
with varying conditions within the grain bed, the calculations here do
not apply.
In order to properly model this system (which I think would be a
colossal waste of time - I'd rather add the proverbial pound of grain
if efficiency is the issue) we need to know some sort of equilibrium
relation between the solution and the grain phase; a "sorption
isotherm" of some sort. That, with a suitable SWAG with regard to the
bed characteristics, might yield useful information. But a) I doubt it
and b) I no longer have students to assign such problems to! But I do
know that the problem has been set up and solved in Carnahan's Applied
Numerical Methods text I used back when Fortran was considered an
advanced programming language.
If properly modelled, I doubt that the batch process would be found to
more efficient. I'll also comment that "efficiency" here could have so
many meanings. Taking the time to solve the mathematical model would
not count as efficient in my opinion. But I digress.
- ---------------------------
On mash viscosity-
I always assumed that beginning homebrew books were just using
improper terminology and that they were referring to wort or extract
liquid viscosity, which does decrease with temperature. The references
provided in recent digests actually measured the viscosity of the mash
itself, and since the grain is stationary during lautering, the mash
viscosity would have no effect on the process - the wort viscosity is
another matter, however. I didn't find the lack of mash viscosity
decrease particularly surprising though - the volume fraction of solids
in the mash doesn't change much and that's the primary factor if you
look at most correlations for viscosity of suspensions (see Einstein's
pioneering work in the field).
So why would mash out help efficiency? Liquid viscosity decreases,
mass diffusivity increases slightly; thus the Schmidt number decreases
and the particle Reynolds number increases (both changes are small).
So there wouldn't be much effect on mass transfer coefficient. The
only thing left is the equilibrium sorption relationship - the isotherm
I mentioned earlier. I would suspect if there's an effect, that's
where we'd find it.
Dave Harsh Cincinnati, OH
Bloatarian Brewing League
------------------------------
Date: Wed, 05 Oct 2005 00:34:48 -0400
From: "Peter A. Ensminger" <ensmingr at twcny.rr.com>
Subject: Re: Mashout temp and viscosity
Yes, the effect is negligible! (as noted by -S in
http://www.hbd.org/hbd/archive/4859.html#4859-2 ). Figure 2d in J Inst >
Brew 111(2): 165-75 is especially relevant. Under the conditions of
these experiments, an elevated mashout temperature (78C=172F) has little
effect on wort viscosity.
Anyone know of an 'el cheapo' viscometer that a poor homebrewer could
afford?
Cheerio!
Peter A. Ensminger
Syracuse, NY
hbd.org/ensmingr
------------------------------
Date: Wed, 05 Oct 2005 06:48:26 -0400
From: Mark Tumarkin <tumarkin at hogtownbrewers.org>
Subject: The Second 2nd Annual Hogtown Brew-Off
The Second Time Around; the "2nd Annual" Hogtown Brew-Off is Back!
After the first 2nd Annual Hogtown Brew-Off was canceled last year due
to a series of unasked-for hurricanes, we're back bigger than ever! This
time,
the Second 2nd Annual Hogtown Brew-Off will be held on Saturday,
November 19th. We're looking for entries in all BJCP categories of Beer,
Mead
and Cider. The competition is sanctioned by both the AHA and the BJCP.
The entry window opens Monday, Oct. 24th and closes Friday, Nov. 11th.
Please check our website at www.hogtownbrewers.org for everything you'll
need
to enter the Brew-off. We anticipate that this page will be fully
functional very soon
with on-line registration for judges, electronic entry forms, and the
full details of all activities.
Check back at the website over the next several weeks for additional
information.
If you're local, or willing to travel, we're going to need help from you
judges to give the
entrants the best possible feedback. And as with the 1st Annual Hogtown
Brew-Off,
we plan to show you a great time! We've got a great new location at the
brand new
Pontiac Tavern. We'll be holding another One Pub Pub-Crawl to Stubbies.
And of course,
we'll have another great award ceremony and dinner, with some great
prizes and an
awesome raffle. So don't miss it - mark your calendars now.
Last time, we got some great entries from Florida and around the
country. We're looking
forward to even more this year.
thanks,
Mark Tumarkin
Please direct any questions to Craig Birkmaier, Competition Organizer
Phone: 352 258-2543 Email: craig at pcube.com
Or judging questions to Dave Williams, Chief Judge
Email: rdavis at gator.net
------------------------------
Date: Wed, 05 Oct 2005 07:43:48 -0500
From: KEITH R BUSBY <kbusby at wisc.edu>
Subject: racking of p-lambics
Am I right in assuming that it is undesirable to rack p-lambics (or sour
beers using Wyeast Roeselaere) to secondary at all?
Keith
Keith Busby
Douglas Kelly Professor of Medieval French
Department of French and Italian
The University of Wisconsin
618 Van Hise Hall
Madison, WI 53706
(608) 262-3941
(608) 265-3892 (fax)
------------------------------
Date: Wed, 5 Oct 2005 08:48:01 -0400
From: Jeff Renner <jsrenner at umich.edu>
Subject: Re: And another thing !
Mike Dixon of Wake Forest, NC wrote about mash viscosity:
> What I do know is that stirring the mash I create at home becomes
> easier as
> the temperature increases from after dough in to mashout. ... I'm fine
> with atrributing it to a lowered viscosity of the mash due to the
> higher
> temperature.
I think it may be due to the mash enzymes acting on the starch and
making it less viscous. I see this all the time at a constant
temperature when doing a cereal mash with corn meal. It noticeably
thins out with time at a constant temperature.
Jeff
- ---
Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu
"One never knows, do one?" Fats Waller, American Musician, 1904-1943
***Please note new address***
------------------------------
Date: Wed, 05 Oct 2005 09:07:33 -0400
From: "Spencer W. Thomas" <spencer at spencerwthomas.com>
Subject: Viscosity
Jeff Renner speculates:
>I think it may be due to the mash enzymes acting on the starch and
>making it less viscous. I see this all the time at a constant
>temperature when doing a cereal mash with corn meal. It noticeably
>thins out with time at a constant temperature.
>
Yup. If you scan the articles that have been thrown around over the
last few days, you'll see a significant correlation between viscosity
reduction and amylase concentration. A couple of them show an
interesting *increase* in viscosity, apparently related to
gelatinization of some malt components during the temperature step up to
the first amylase rest. This makes it pretty clear that temperature is
*not* the major determinant of viscosity in a mash.
=S
------------------------------
Date: Wed, 5 Oct 2005 06:56:09 -0700 (PDT)
From: Steven Parfitt <thegimp98 at yahoo.com>
Subject: RE: Subject: efficiency, 1/ batch sparge analysis
steve does a nice job of laying out the analysis of
batch vs fly (or imcremental) sparging.
<Well my face may red, but it's others acting like
<baboons here. Continuous sparge is LESS efficient
<than batch in the general case.
<But it requires some detailed analysis to see why.
...snip...
<Now all mashes start with a volume of mash water M,
<and we assume that after the relatively long mash
<period that the extract both in and outside the grist
<are near equilibrium.
Ah-Ha! But are they really near equilibrium? How long
does it take to reach this equilibrium? Is a 40 minute
mash followied by a 20 minute drain, and 20 minute
wait before draining the second sparge enough?
If not, then the equations need to be driven by the
differnece between in extract solution and not in
solution in which case fly sparge creates a greater
differnetial to drive the equations.
Therefore, IF one waits long enough to reach
equilibrium batch sparge will be more efficent. But
fly sparging may be more efficient if sparging is done
before equilibrium is achieved.
Steven, -75 XLCH- Ironhead Nano-Brewery http://thegimp.8k.com
Johnson City, TN [422.7, 169.2] Rennerian
"There is no such thing as gravity, the earth sucks." Wings Whiplash - 1968
------------------------------
Date: Wed, 5 Oct 2005 09:58:48 -0400
From: "Dave Burley" <Dave_Burley at charter.net>
Subject: Sparge efficiency, Mash out and CharlieP
Brewsters:
SteveA insists that batch sparging is more efficient than continuous
sparging in terms of removing soluble sugar and expends several pages with
his examples to try to prove it, denying Chemical and Chemical Engineering
concepts to the contrary.
Here is a simple way to think about it.
At the end of the sparge in either case, the wort coming from the sparge has
a certain specific gravity. We know for sure the wort inside the grain is
probably more than the wort but If we make the simple assumption (not really
true) that the specific gravity of the wort inside the grain is the same as
the wort outside the grain, then we can see that with the batch sparge, in
which the final sparge has a specific gravity of say 1.030 or whatever, and
the continuous sparge has a value of 1.006 or less, there will be a clear
difference in the amount of sugar left in the grain. I leave it up to the
student to calculate the amount of sugar left in the grain in both cases,
given that after the mash about a pint (I think) of water is contained in
each dry pound of malt.
Clearly the lower specific gravity at the end of the sparge, in the case of
the continuous sparge, indicates the better efficiency of this process since
there is less sugar absorbed in the remaining brewer's grains. Now go back
and examine the original assumption and you will see an even bigger
difference, since the continuous sparge allows the establishment of an
equilibrium of the wort in the grain with the sparge water and the much
shorter time of the batch sparge likely does not, as studies on the
efficiency of different rates of continuous sparge would indicate. Faster
sparges are less efficient.
When you realize that in the continuous sparge, the exiting specific gravity
is the highest value in the whole column of grain and then go back and
re-examine these cases, it becomes even clearer.
Try the experiment I suggested in which these two sparging methods are done
with the same batch. Then add the same <volume> (say 4 cups) of drained
brewer's grains to the same amount of water (maybe a pint to cover) and
allow it to stand overnight. Measure the sugar concentration of the water in
each case with Clinitest and you will find the batch sparge will have the
higher concentration, proving it is less efficient.
- ---------------
Steve, the reason for the temperature boost at the end of the mash (aka
mashout) has nothing to do with the viscosity change (which is in fact lower
at the higher temperature, as we both now agree) but is done to clean up any
starch - avoiding a "Blue mash", as the Germans call it, and to stop any
enzyme action. Co-incidentallly, the lower viscosity of the wort will allow
faster draining and most likely a faster establishment of equilibrium at the
higher temperature, and, although I have never seen the wort viscosity given
as the reason for the mashout, I agree with you a lower mash viscosity is
not the raison d'etre. Pardon my French.
- ---------------
Steve, I wasn't denigrating CharlieP by using his own description of himself
(which I find quite amusing as I do some of his other clever attempts at
humor), just pointing out the origin of the "add another pound of malt" and
the state of the art when CharlieP wrote that. I doubt that today he would
say that, just like he now knows how to do an iodine test including the
grain and recommends longer mashes and not to spray hot wort through the
air. In fact, I think CharlieP has done a great thing for the Home Brewing
industry in the US and around the world and his position and big paycheck
(clearly more than a grade school teacher) shows people appreciate that.
- --------------
And you couldn't see me smiling when I wrote that "graininess" flavor thing,
just to get your back up. {8^) I do find, however, that continuous sparging
does give a more complex flavor to the beer, compared to batch sparged and
malt extract beers. Whether or not a bunch of other unknown people with
other unknown preferences and experience (without commenting on the
difference in complexity) prefer it or not is irrelevant.
Keep on Brewin'
Dave Burley
------------------------------
Date: Wed, 5 Oct 2005 10:33:35 -0500
From: "Craig S. Cottingham" <craig at cottingham.net>
Subject: Re: Wort Chiller Efficiency
On Oct 4, 2005, at 07:29, Pete Limosani <peteLimo at comcast.net> wrote:
> I'm trying cut down on my water usage during a brew session.
>
> I boil about 7.5 gallons down to 6 and use an immersion chiller to
> cool it.
> It generally takes 20-25 minutes to get from boiling to 70-75*.
>
> When I first start cooling I open up the valve full throttle and the
> water
> escaping the chiller is steaming. The difference in temperature
> between water
> entering the chiller and exiting the chiller is great. As the wort
> cools down,
> the difference in temperature closes and it takes longer to drop that
> next
> degree.
>
> As the difference in temperature decreases, I am tempted to slow the
> amount
> of water running through the chiller to save water. My thinking is
> that less
> water will be used, but the water may extract a couple more degrees
> while
> it is travelling.
>
> Is my logic flawed?
At first, I thought this was going to be easy to answer. Then I thought
about it some more, and realized it was more difficult. Then I thought
some more, and I realized it was a *lot* more difficult. A gut feeling
became algebra, which became differential equations. Too many years
(and beers) have passed since college; I don't have the math muscles I
used to.
So it's back to the gut feeling.
> Will I use less water over the whole cooling cycle by keeping it wide
> open?
I'm confident answering "no" to this.
Heat transfer is a function of temperature differential and time. The
greater the difference in temperature between the wort and the cooling
water, the faster heat will flow from one to the other. The *quantity*
of heat that's transferred is this rate times the amount of time that
the cooling water is in contact with the wort.
Twenty feet of 3/8" OD copper tubing has an interior volume of about
0.075 gallons (a little less than 1 1/4 C). My kitchen faucet can fill
a gallon jug in a little over 30 seconds (for a flow rate of about 2
gal/min), and I expect without hard evidence that my garden hose could
do it faster. At 2 gal/min, water goes from one end of your immersion
chiller to the other in about 2 seconds. When the wort has just
finished boiling, that's enough time to soak up a fair amount of heat,
but as the wort temperature drops, less and less heat flows in that 2
seconds. You can't increase the rate of heat transfer -- in fact, it's
going down, because the temperature differential is going down -- so
you have to increase the amount of time heat has to transfer.
In other words,
> Or will I use less water by slowing the flow and waiting a little
> longer?
Yes.
> How do I find the best balance between the rate of flow and the rate
> of heat
> extraction?
This is where it gets interesting. We could use math -- okay, maybe you
could use math; I can't, because I've forgotten the necessary math
skills. :-) So let's try to approach it empirically.
Since heat flows only when there's a difference in temperature, the
cooling water will never get hotter than the wort. But if the
temperature of the cooling water at the exit is lower than the
temperature of the wort, we're leaving money on the table; there was a
little more potential for heat transfer. What we should be aiming for
is for the exit temperature of the cooling water to be the same as the
wort temperature.
You could set up thermometers in the wort and the exit of the chiller,
and monitor them closely, continuously reducing the flow rate of the
cooling water... or you could relax and drink whatever you made the
last time you brewed. Start your cooling water full bore. As you clean
up, occasionally feel the water coming out of the chiller; as soon as
you notice it feels cool or tepid instead of warm or hot, turn the
water down.
Hope this helps.
- --
Craig S. Cottingham
craig at cottingham.net
OpenPGP key available from:
http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x7977F79C
------------------------------
Date: Wed, 5 Oct 2005 09:13:13 -0700
From: "Mike Sharp" <rdcpro at hotmail.com>
Subject: RE: Wort Chiller Efficiency
Pete Limosani asks about Wort Chiller Efficiency:
"I'm trying cut down on my water usage during a brew session."
If minimizing water use while chilling is important, use a counterflow
chiller. It's much more efficient than an immersion chiller (though a bit
more of a pain to use).
Regards,
Mike Sharp
------------------------------
Date: Wed, 05 Oct 2005 13:02:31 -0400
From: Mark Tumarkin <tumarkin at hogtownbrewers.org>
Subject: The Second 2nd Annual Hogtown Brew-Off
The Second Time Around; the "2nd Annual" Hogtown Brew-off is
back!!
After the first 2nd Annual Hogtown Brew-off was cancelled
last year due a series of unasked-for hurricanes, we're back
bigger than ever! This time the Second 2nd Annual Hogtown
Brew-off will be held on Saturday, November 19th. We're
looking for entries in all BJCP beer, cider & mead
categories. The event is sanctioned by both the BJCP & AHA.
The entry window opens Monday, Oct 24th & closes Friday, Nov
11th.
Please check our website at www.hogtownbrewers.org for all
info concerning the Brew-off. We anticipate that this page
will be fully functional very soon with electronic entry
forms, online judge-entry, and full details on all activities.
Check back at the website over the next several weeks for
addtional info. If you're local, or willing to travel, we're
going to need help from you judges to give the entrants
the best possible feedback. And as with the 1st Annual
Hogtown Brew-off, we plan to show you a great time! We've
got a great new location at the brand new Pontiac Tavern.
We'll be holding another One Pub Pub-Crawl to Stubbies. And
of course, we'll have another great award ceremony & dinner,
with some great prizes and an awesome raffle. So don't miss
it - mark your calendars now.
Las time, we got some great entries from Florida & around
the country. We're looking forward to even more this year.
thanks,
Mark Tumarkin
Please direct any questions to Craig Birkmaier, Competition
Organizer craig at pcube or to Dave Williams, Chief Judge at
rdavis at gator.net
------------------------------
Date: Wed, 05 Oct 2005 13:18:09 -0500
From: Bill Velek <billvelek at alltel.net>
Subject: Steve Alexander and Steve Jones re Efficiency and Batch Sparging
Steve Alexander: those were outstanding posts you wrote containing the
mathematical proof that batch sparging is actually more efficient than
fly sparging. Thank you.
I do have one question, though. Early in your first post, you stated:
"Let's say we have X volume units of soluble extract (when in solution)
and let's just estimate that this has some density in solution around
1.55 times that of water - close to mash extract, so the mass of extract
is then X * 1.55."
Was that extraneous info, or does it relate in some way to the math you
have done? No problem if it's extraneous, except that it initially
caused me some slight confusion as I looked for it later in your post.
I say that because the "1.55" constant never appears again anywhere in
your math, nor can I find where you have substituted it with a variable.
Am I missing something?
- ---
Steve Jones: until Steve Alexander posted his mathematical proof, I was
very much persuaded by the apparent logic of your post. After looking
at his math, I felt compelled to sort out the logic to try to figure out
why they didn't seem to agree. I _think_ I have it figured out now. I
think that all of your premises were/are correct, but I think that you
and I both jumped to the wrong conclusion. While it is no doubt true
that the SG of the final 'batch' will always be higher than the SG of
the final runnings on the fly (continuous sparging), that doesn't
logically mean that there is more sugar left behind in the grain bed,
like I think we each assumed. I think the answer is that we should not
consider the SG of the final batch that is _drained_, but rather we
should consider what would be the SG of the tun when it is refilled with
the same volume as remains when the fly sparging is stopped. I think,
based on the math, that we would find that when it is diluted (as if we
were planning to do a third batch sparge), that the SG of the 3rd batch
would be lower than the SG of what remains at the end of a fly sparge.
I hope I'm making some sense here.
- ---
Thanks again to everyone; this was all very interesting and thought
provoking, but now I have a couple of follow-up questions: in another
brewing forum, I was advised of the importance of "floating" the grain
bed in the tun by minimizing stirring in order to allow air to remain
trapped in the grist. But it is my understanding that when batch
sparging, new sparge water is stirred into the grain bed to dissolve
remaining sugars. Because of the stirring, I assume that the bed does
not float, per se; is that true, and does it matter when batch sparging?
If the bed doesn't float, are there more stuck mashes associated with
batch sparging?
Thanks for any further info.
Bill Velek
------------------------------
Date: Wed, 5 Oct 2005 15:59:11 -0500
From: "rkolacny" <rkolacny at mail.ev1.net>
Subject: Dixie Cup XXII call for judges
ATTENTION:
Beer Judges Needed!!!
It is Dixie Cup time again! and we will start judging the Dixie
Cup XXII entries soon. Please, come be a part of Dixie Cup and
help us judge. We need beer judges of all skill levels to come and
help out. Don't worry if you are not BJCP ranked. We will either
put you on a panel with experienced judges or use you as a
steward. Everyone can be a beer judge!!!
Here is the judging schedule:
10/16 First round judging at Saint Arnold Brewing Company from 9
AM to 4 PM.
10/18 First round judging continues at Saint Arnold Brewing
Company from 6 PM to 10 PM. (This judging session is contingent
upon progress made on Sunday).
10/21 First round judging continues Noon -
10/22 Second round judging Noon -
That's it! Please come out and give generously!
Na zdravi (to your health or cheers!)
Rob Kolacny
Dixie Cup Coordinator
http://www.crunchyfrog.net/dixiecup/
Secondary Fermenter
Foam Rangers
www.foamrangers.com
rkolacny at ev1.net
979 532 8056 wk
979 532 1932 hm
979 533 1173 cell
------------------------------
End of HOMEBREW Digest #4862, 10/05/05
*************************************
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