---

	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
		Digest Janitor: pbabcock at hbd.org


***************************************************************
        TODAY'S HOME BREW DIGEST BROUGHT TO YOU BY: 

                 Sponsor The Home Brew Digest!
     Visit http://www.hbd.org/sponsorhbd.shtml to learn how
			 
    Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********

DONATE to the Home Brew Digest. Home Brew Digest, Inc. is a 
501(c)3 not-for-profit organization under IRS rules (see the
FAQ at http://hbd.org for details of this status). Donations
can be made by check to Home Brew Digest mailed to:

HBD Server Fund
PO Box 871309
Canton Township, MI 48187-6309

or by paypal to address serverfund@hbd.org. DONATIONS of $250 
or more will be provided with receipts. SPONSORSHIPS of any 
amount are considered paid advertisement, and may be deductible
under IRS rules as a business expense. Please consult with your 
tax professional, then see http://hbd.org for available 
sponsorship opportunities.
***************************************************************


Contents:
  Re: Heat calculations and thermal mass (Matt)
  Lansing Water ("A.J deLange")
  Thermal Mass of Mash Tuns ("A.J deLange")
  Re: Thermal Mass (Joe Walts)
  Re: Heat calculations and thermal mass (Calvin Perilloux)
  Boston Homebrew Competition - Call for Judges (Eric Wooten)
  Thermal Mass (Kevin Elsken)


* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*           The HBD Logo Store is now open!             *
*            http://www.hbd.org/store.html              *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*   Beer is our obsession and we're late for therapy!   *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *

NOTE: With the economy as it is, the HBD is struggling to 
meet its meager operating expenses of approximately $3400
per year. If less than half of those currently directly
subscribed to the HBD sent in a mere $5.00, the HBD would
be able to easily meet its annual expenses, with room to 
spare for next year. Please consider it.

As always, donors and donations are publicly acknowledged
and accounted for on the HBD web page. THank you

 
Send articles for __publication_only__ to post@hbd.org

If your e-mail account is being deleted, please unsubscribe first!!

To SUBSCRIBE or UNSUBSCRIBE send an e-mail message with the word
  "subscribe" or "unsubscribe" to request@hbd.org FROM THE E-MAIL
  ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!**
IF YOU HAVE SPAM-PROOFED your e-mail address, you cannot subscribe to
  the digest as we cannot reach you. We will not correct your address
  for the automation - that's your job.

HAVING TROUBLE posting, subscribing or unsusubscribing? See the HBD FAQ at
http://hbd.org.

LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go
instead to http://homebrewfleamarket.com and post a free ad there.

The HBD is a copyrighted document. The compilation is copyright 
  HBD.ORG. Individual postings are copyright by their authors. ASK 
  before reproducing and you'll rarely have trouble. Digest content 
  cannot be reproduced by any means for sale or profit.

More information is available by sending the word "info" to 
req@hbd.org or read the HBD FAQ at http://hbd.org.

JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning,
                  and Spencer Thomas



----------------------------------------------------------------------


Date: Wed, 18 Feb 2009 20:42:02 -0800 (PST)
From: Matt <baumssl27 at yahoo.com>
Subject: Re: Heat calculations and thermal mass

> I am wondering what is the cause of this discrepancy.

Slaking heat!  The hydration of malt involves chemical
reactions that release significant amounts of heat.  Thus
it *appears* to require less heat than expected to bring
the cold mash tun up to mash temp.  

For not very detailed details, take a look at Malting and
Brewing Science by Briggs and Shanks on google books, and
search for "slaking heat."  A 5F temp shift is indicated
under pretty standard conditions.

For single infusion mashes at 150F at 1.5 qt/lb in my
system, the two effects cancel well enough that I routinely
ignore them both and hit mash temps to within 1F (and I
don't measure my strike water volume with much care, either).

Unfortunately it's not always so easy.  Mash tun thermal
mass and slaking heat have different effects under different
mash conditions and a single "fudge factor" can't account
for both of them at once.  More calculation complexity is
needed to account for them well.  Further, theoretical values
are not easy to come by and at least for me the numbers in
the above reference don't work well (half works much better).
This is not surprising given the complex nature of the
reaction, different malt grinds, many variables, etc.
I think one would have to be very lucky to arrive at a formula
to predict mash temps to within, say, 1F on a given system
without some fairly thorough observations of different mashes
on that system.

Matt


      


Return to table of contents


Date: Thu, 19 Feb 2009 08:08:02 -0500
From: "A.J deLange" <ajdel at cox.net>
Subject: Lansing Water

The water in question has Ca: 20, Mg: 9.7, Na: 44, SO4: 70; Cl: 46,  
HCO3 42.1 all assumed to be mg/L which is a reasonable assumption as  
those units cause the profile charge imbalance to be only 4% which is  
pretty good i.e. the profile is consistent (I assumed pH 7.5 at 20 C).  
This water is not very hard (total hardness 89.8 ppm as CaCO3 of which  
37 is temporary) nor very alkaline (37 ppm as CaCO3) with a very  
modest Residual Alkalinity of 17 ppm as CaCO3 from which an upward pH  
shift (relative to distilled water) of only 0.03 is to be expected.  
IOW no action should be required to set mash pH with base malts and  
even a small amount of colored malt should result in a good value.

The water is well undersaturated with respect to calcium carbonate  
i.e. no calcium carbonate would be expected to precipitate upon  
standing but somewhat over saturated with respect to CO2 so that gas  
can be expected to escape over time with a gradual increase in pH.

It has fair amounts of sulfate and chloride so beers made with it may  
have a round, full bodies character and hops will be perceived as  
somewhat dry and a bit rough. You couldn't use this water for delicate  
continental lagers or similar beers because of the sulfate. There may  
be a mineral crispness to beers made with this water and perhaps a  
hint of saltiness (does it taste salty from the tap?).

Adding gypsum at the rate of 0.5 gram/liter (12.5 grams in 25 L)  
obviously increases the sulfate  (to 349 mg/L) and the  calcium  
hardness (total to  380 while temporary hardness stays the same as the  
hardness exceeds the alkalinity) dramatically. The extra calcium  
decreases the residual alkalinity to -67 ppm as CaCO3 which predicts a  
decrease of mash pH (relative to a distilled water mash) of 0.11 pH.  
Because a lot of doubly charged ions (Ca++, SO4--)have been added the  
ionic strength changes enough to induce a small pH shift in the water  
itself (about 0.02 pH in the acid direction) but the water is still  
undersaturated (saturation pH is 7.83) with respect to calcium  
carbonate because the alkalinity is so low below 1 mEq/L (50 ppm).  
Adding gypsum does not change alkalinity.  It, therefore,  not likely  
that boiling will cause anything to precipitate (as it would in harder  
waters with higher alkalinity). Boiling, as a rule of thumb, reduces  
hard, carbonate water alkalinity down to about 1 mEq/L (50 ppm as  
CaCO3) and this water is below that (even post treatment).

All the information extracted from the basic water report presented  
here came from my water analysis spreadsheet which is at
http:/www.wetnewf.org/Brewing_articles/BURP_OCT08
IOW, you can get all this info yourself if you are so inclined though  
expect to spend some time trying to figure the thing out. There are  
extensive instructions but I know this is complex stuff (based on how  
many years it has taken me to get this far).

A. J.


Return to table of contents


Date: Thu, 19 Feb 2009 09:17:20 -0500
From: "A.J deLange" <ajdel at cox.net>
Subject: Thermal Mass of Mash Tuns

It's been a while since we did the algorithms for ProMash so I'd have  
to go back and look at some notes but as I recall the big problem with  
pouring hot water into a tun at room temperature is that the water  
loses so much heat in the transfer that it throws the calculation off.  
Thinking it over it seems a better way might be to fill the tun with a  
known mass of  water at room temperature, heat the water to a few  
degrees above room temperature, let it equilibrate (stand for an hour  
or so with occasional stirring) or put some hot water in the tun and  
let it stand, with stirring, until its temperature is a few degrees  
above room temperature and then add a known mass of water at room  
temperature. This prevents heat loss from either the water in the tun  
(even if it's a few degrees above ambient some heat will be lost but  
the rate of loss is proportional to the temperature difference) or the  
water added. Note that I say known "mass" of water. Probably the best  
way to do this would be to put the tun on a scale. When its empty you  
have its weight (not that you really need that) but you can tare it to  
measure the mass of warm water and then take the difference after you  
add the cooler water. I'm talking mass here because the volume of  a  
given mass of water does change appreciably with temperature (several  
percent). Another thing to be aware of is that the heat capacity of  
water does change somewhat as a function of temperature. I handled  
this relatively simply by computing an average over any given  
temperature range i.e. if you go from T0 to T1<T0 when you add cold  
water the average heat capacity is simply  (1/(T0- 
T1))*Integral_from_T1_to_T0[Cp(T) dT)]. You can find Cp(T) in  
handbooks, Wikipedia etc. Errors induced by ignoring this will be much  
smaller than errors induced by ignoring density changes and being  
unable to control heat losses.

A.J.


Return to table of contents


Date: Thu, 19 Feb 2009 08:33:03 -0600
From: Joe Walts <jwalts at gmail.com>
Subject: Re: Thermal Mass

Hey Bill, just a couple of quick and dirty guesses here:

First off, you're not raising the temperature of your entire mash tun to the
desired mash temperature.  Instead, you're creating a gradient through the
vessel walls where the inside surfaces are at the mash temperature and the
outside surfaces are at ambient temperature.  The latter scenario requires
less heat energy from the strike water,  Unless you model the gradient in
your heat capacity calculation, your experiment will result in a lower
thermal mass.

The second complication is the time.  How long does it take the system
become stable, i.e. to where you're slowly losing heat to the atmosphere
instead of to the vessel itself?  I have no idea, so I just overheat my
strike water by 10 degrees, dump it in the mash tun and wait to add the
grain until the water cools to my desired strike temperature (which doesn't
include the thermal mass of the mash tun in its calculation).

Joe


Return to table of contents


Date: Thu, 19 Feb 2009 06:56:39 -0800 (PST)
From: Calvin Perilloux <calvinperilloux at yahoo.com>
Subject: Re: Heat calculations and thermal mass

Regarding Bill Pierce's formulas for thermal mash...
That's good research for an English major, Bill!  ;-)

>  0.119*32.92 = 3.92
> Unfortunately this is in conflict with the value
> I arrived at (1.918 lbs.) based on my formula and
> experiment with hot water as described above.

You are now into the scientific area best explained by this quote:

 "Well, that's great in practice, but does it work in theory?"

Without delving too much into the formulas, and not having my
trusty CRC handbook nearby anyway, I'll highlight a few things
to consider, not only for your setup but for others:

The structure of your vessel can have some significant effect.
In the case of a converted keg, the heavy rings top and bottom
are to some extent isolated from the rest of the body.  Sure,
it's thermally attached as one piece of stainless, but my guess
is that the conduction might not be great enough to rapidly
heat those.  That would leave the body of the keg absorbing
most of the heat and not the edges.  

So in your empirical tests it could show a lower thermal heat
because those outer areas are not being heated (as much).

In other cases, such as people using stainless pots for mash
tuns, the handles are a minimal factor (as above), but keep
in mind that there is often an aluminum layer in the base
(for heat distribution because stainless is such a poor heat
conductor), and this might make it hard to get the results
just right on paper -- do you know how much the alu-sandwich
inside there weighs?

There is also the heat loss that you encounter in bringing
the hot water to the mash tun and pouring it.  I find that
this is not that large but definitely not insignificant.

In my own opinion, the very best way to do this is to just
do the empirical work on your own system and use that number.
When you do that, the heat loss, mixed-metal proportion, and
structural features will all be accounted for in your end result.

Calvin Perilloux
Middletown, Maryland, USA



Return to table of contents


Date: Thu, 19 Feb 2009 10:19:58 -0500
From: Eric Wooten <ecwooten at gmail.com>
Subject: Boston Homebrew Competition - Call for Judges

The 14th Boston Homebrew Competition is coming up on Saturday, February
28th. It will be held at the law offices of Holland and Knight, located in
the Back Bay region of Boston about 2 blocks from the Public Garden (Back
Bay and Arlington Stations are within easy walking distance for those
traveling by MBTA). Preliminary counts yield a total of 271 entries this
year (the entry window is now closed). We are still looking for both
experienced and novice judges and stewards to help with this years
competition.

If you are able to help with judging or stewarding, please fill out the
judge registration form at http://bhc.wort.org/judgereg.shtml.
Further details about the judging process can be found at:
http://bhc.wort.org/judgeinfo.shtml. Although the competition site is easily
accessible by the T and Commuter Rail, on site parking is available and the
competition will cover parking fees for all individuals who register in
advance.

Important Note: As the competition will be held in a secured building,
pre-registration to judge or steward is required. Building security needs a
list of people to provide to their check-in desk in advance of the
competition.

If you have already signed up to help out: thanks in advance for helping us
put on another great competition; Mark Irwin, the judging coordinator for
BHC 14, will be contacting you soon with the final details. If any of you
have any questions please do not hesitate to contact us.

Eric Wooten, Competition Organizer (organizer at wort.org)
Mark Irwin, Judging Coordinator (irwin at wort.org)
Wade Hicks, Entry Organizer (treasurer at wort.org)


Return to table of contents


Date: Thu, 19 Feb 2009 21:17:27 -0500
From: Kevin Elsken <littleboybrew at verizon.net>
Subject: Thermal Mass

Bill,

First of all, for goodness sakes man, come over to the dark side and 
just use the metric system!  It is just so much better and easier.

Anyway, I have gone through many turns trying to hammer out thermal mass 
values to give consistent mash temperatures.  I suspect won't be the 
first to mention that your calculation implies your entire mash tun was 
heated from 70 def F to 157 deg F.   In truth, only a portion of the 32 
lb+  tun is actually increasing in temperature from 70 to 157.  The 
converted kegs have heavy rolled rings around the top and bottom that 
most certainly did not change temperature that much.  According to the 
quick calculations I made, the water lost about 176 kJ, but it would 
require almost 361 kJ to raise your mash tun from 70 to 157 F.

Incidentally, insulated coolers are primarily polyurethane foam, which 
has a heat capacity of about 1.5 kJ/kg.  The trick to the calculation 
with an insulated cooler is that due to the excellent insulation value 
of the cooler, the outside remains at ambient temperature, so the actual 
temperature rise is only about one half the difference between the 
inside and outside of the cooler.

Kevin Elsken
Little Boy Brewery
Upper Saint Clair, PA


Return to table of contents

---