---

	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:
  Brix and SG ("A.J deLange")
  Berliner Weisse ("T. Rohner")
  RE:   Brix to Specific Gravity ("Mike Patient")


* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*   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 $3500
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.

Financial Projection As of 04 Jun 2010
       Projected 2010 Budget  $3305.65
 Expended against projection  $1066.11
Projected Excess/(Shortfall) ($940.36)

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: Tue, 8 Jun 2010 01:17:16 -0400
From: "A.J deLange" <ajdel at cox.net>
Subject: Brix and SG

For Jim: Apparently you are seeking the relationship between the  
concentration of a wort  and its specific gravity. In modern brewing  
this is modeled based on the work of the Normal-Eichungskomission of  
1900 under the leadership of Leo Plato. He measured the true specific  
gravity (density at 20  C normalized by the density of water at 4 C)  
of pure sucrose solutions (as did Brix and Balling before him) and so  
when we do these interconversions we assume that wort is pure sucrose  
which, of course it isn't, but other sugars behave nearly identically  
to sucrose and so it is a good model not to mention that sucrose is  
easy to purify and is not hygroscopic so it can be accurately weighed  
out. The ASBC and EBC have taken the approach of taking apparent  
specific gravities (20 C/20 C) ranging from 1.00000 to 1.08300 in  
steps of 0.00005, converting these to true (in vacuo) values entering  
these into the Plato tables and taking out the percent sugar by weight  
for each specific gravity. Interpolation between adjacent Plato table  
entries was done as required. ASBC and EBC publish the result in  
tables found in the ASBC MOA's and in Analytica and these are the  
"official" basis for all concentration/SG calculations. Because these  
tables are based on Plato's work the units of concentrations (grams of  
sucrose per 100 grams of solution) are referred to as "degrees Plato"  
or just P. One enters the table with specific gravity and takes out  
degrees P.

To replace the tables with a formula requires a curve fit. As you  
noted the relationship between P and SG is almost, but not quite  
linear. Curve fitting is a bit of an art and there are several options  
available to the analyst. The ASBC publishes (in the MOAs) a third  
order polynomial fit to the data in the table: P =(((135.997*S -  
630.272)*S + 1111.14)*S - 616.868). This polynomial provides rms  
agreement with the table of 0.00061P with a maximum error of 0.0038P  
at SG = 1 (i.e. it doesn't go through 0 at SG 1.00000) but, as we  
seldom deal with worts weaker than 1 P it is a very good  
representation of what is in the table. It is, of course, possible to  
make higher order fits which are forced to go through 0 or others  
which emphasize a particular region (say 7 - 15 P) and one is, of  
course, free to do that but the ASBC polynomial represents the  
industry standard and should, therefore, always be used.

But you want to go the other way; from Plato to SG. The only "correct"  
way to do this is by finding the value of SG which causes the ASBC  
polynomial to evaluate to the desired value of P. There are a couple  
of ways to do this. The ASBC polynomial is third order and so closed  
form formulas for the roots can be written and the correct one chosen.  
It takes a fair amount of algebra to get to the root to the point that  
it is actually easier to code an iterative root finder and this is  
what ProMash does. The reason it does it that way is so that if you  
feed ProMash a specific gravity of 1.040 is will use the ASBC  
polynomial to calculate   9.99353 P and if you feed it 9.99353 P it  
will return exactly (to machine precision) 1.040.

You can, of course, fit the ASBC table to come up with a polynomial  
for SG as a function of Plato. S = (((6.34964E-8*P + 1.27447E-5)*P +  
0.00386777)*P + 1.0000131) is such a polynomial and it is quite good.  
For example S(6) - root(6) =  2.19009e-06 where root( ) is a function  
that iteratively inverts the ASBC polynomial. Thus we would expect S  
and the ASBC polynomial to close pretty tightly e.g.  S(P(1.040))  
=1.04000198755817 where P( ) is a function that converts whatever  
specific gravity is in the parentheses to Plato by the ASBC polynomial  
and S_G( ) is a function that converts whatever is in the parentheses  
to specific gravity using the inversion polynomial. Note that in  
ProMash,   root(P(1.040)) = 1.04000000031739 when the root bisector is  
set for a tolerance of 1E-9.

Looking at the numbers in your table 6.000P interpolates to 1.02369166  
in the ASBC table. root(6) = 1.02369005432759 and S(6) =  
1.0236922444224 so the inverse fit polynomial is closer to the table  
than inversion of the ASBC polynomial (which isn't too surprising  
since a simple fit to the table gives a polynomial slightly different  
from the ASBC polynomial. But the inverse of the polynomial must be  
considered the "correct" answer as it closes with the official  
polynomial. Since ProMash uses the inverse it should return 1.02369  
for 6 P input. For 9 P it should return 1.035899639 and for 12 it  
should return   1.0483692. The fact that the values you obtained from  
ProMash are different suggests that something is wrong. The 1.02277  
corresponds to 5.771 P and 1.04644 corresponds to 11.54 P which are  
way off - i.e. too far off even to be explained by the small  
differences between the actual Brix scale and the Plato scale. I can't  
believe ProMash has become "broken" to this extent. It checked when I  
worked with Geoffrey on these algorithms but that has been years.  
Could you check those ProMash numbers?

Bottom Line: S  = (((6.34964E-8*P + 1.27447E-5)*P + 0.00386777)*P +  
1.0000131) is an inverse fit to the ASBC table data and is good for  
almost any purpose. To 5 decimal places it gives answers identical to  
your number (3).
                         An exact inverse of the ASBC polynomial may  
actually be less accurate (because the ASBC polynomial isn't the best  
fit to the table) but is to be preferred because it has the imprimatur  
of the ASBC upon it.

A.J.




Return to table of contents


Date: Tue, 08 Jun 2010 11:30:42 +0200
From: "T. Rohner" <t.rohner at bluewin.ch>
Subject: Berliner Weisse

Hello all
i was reading the posts on "Berliner Weisse" with much interest. A 
couple of months ago, i was looking for information on the subject.
It doesn't seem to be a very popular style among homebrewers. I can 
imagine why...
After some internet research, i found a pretty easy way to let the 
lactos do their work, while still using a bacterial-free fermentation 
regime.
The "four No's" way seems a bit adventureous to me.(I didn't try it..) 
The way i do it, is tweaked a bit from the original way i found on the 
internet. The way i read about, is closer to the "four no" method.
Here the way i did it: (i use SI units...)
Malt: 4kg wheat, 3kg pilsner (Weyermann)
I mashed 90% of the grist at 63 C for 45 min
then 30 min at 71 C.
Then i cooled it down to 48 C and added the remaining 10% of the 
grist.(for the lactos on the malt)
I let it sit for 14 hours for the lactos to do their work.
Then i heat it up to 63 C again for 30 min, then to 71 C for another 30 
min and then to 77 C for mash-out.
After lautering, i boil it for 60 min and add a little hop for 30 min.
I fermented it with a mixture of American Ale and Wheat yeast.(Both dry 
yeast from Fermentis) I did this, because i remember the beer in Berlin 
as relatively clean tasting.(Not very wheaty...)

The smell of the sour mash in the morning was a bit strange at first, 
but when we bottled the first batch, i was pretty confident, that it 
turns out nice.
Now, after having brewed 3 batches(150litres), we are very happy with 
the results. Even my SWMBO who doesn't drink "normal" beers, judged it 
very positively.(Not only verbally, but she drank a imperial pint of it 
with our woodruff sirup.)
In Berlin, many people drink it with "Schuss", which is a shot of 
raspberry or woodruff sirup. It takes a little sourness out. After 
having tried our product in the pure form, i went in the forest to 
gather some woodruff to make sirup. The sirup turned out very nice and 
with some green food colorant it looks like the commercially sold version...

If there is some interest in a more detailed recipe, i could post it, or 
even send the Promash file.

Cheer Thomas



Return to table of contents


Date: Tue, 8 Jun 2010 11:48:33 -0400
From: "Mike Patient" <mpatient at rta.biz>
Subject: RE:   Brix to Specific Gravity 

I have been making brewing software in my free time and have been looking at
various resources for formulas.  

Wikipedia defines brix as 261.3 x (1-1/g)
Making g 1-(261.3/b)

This is also a linear formula, and my bet is that in reality it isn't.
However, the relationship might be pretty close to linear for the range
acceptable for brewing.  I am not sure if it is the case.  

If anyone has more info, I am quite interested as well.

Mike



Return to table of contents

---