pH discrepancy between Martin and Kai's water sheets?

Brewing Processes
1

Perhaps Martin Brungard and/or Kai are able to weigh in on this…

I’ve been using Kai’s water sheet for my last couple beers (German Pils, Helles, a Maibock coming up next week) and with all the recent chatter on this board about Bru’n Water, thought I’d check it out as well.  And I’m having trouble getting the predicted pH to match up. As a test, I used Kai’s “Pilsner Water” recipe which calls for 100ppm Gypsum, 85ppm Epsom, and 130ppm CaCl2 added into distilled water, and a grist of 98% Pils and 2% Acidulated. Both worksheets match up at this point, telling me to add the same amounts of the right salts, giving RA of -47, etc etc.

But it is in the next step that things go south. I loaded my basic pils parameters into both sheets: 17.64lbs pils malt, 0.36lbs acidulated, mash at 2qts/lbs (9 gallons strike water) and collect a total of 16 gals pre-boil, which is boiled to 11 gallons.  And somehow Kai’s sheet is giving me predicted pH of 5.36 (which would be nice), and Martin’s is saying 4.9, which is too low.

Can anyone confirm something similar? Or are these sheets always going to differ in how they calculate pH from the SRM? Or am I doing something wrong?  I believe I have zeroed out all things like lactic acid additions in Martin’s sheet but maybe I missed something.  Kai or Martin, I can email my working copies of your sheets to you if you want to check them out.

thanks, Red

2

Did you see Martin’s recent note about the different levels of acid in the two brands of acid malt?
http://www.homebrewersassociation.org/forum/index.php?topic=6407.0

3

I did… aren’t both Kai’s sheet and Martin’s sheet are assuming the 3% acid malt? …which is what I’m using (Weyermann)

4

Interesting results.

Since you’re starting with distilled water and adding hardness, its apparent that the RA will be negative.  Therefore, it should not be necessary to add acid malt in the first place.  You’re setting yourself up for a disappointingly tart beer with that addition.  The mash pH will be perfectly fine without the acid malt.  The use of acid malt is only needed when a brewer’s water has excess alkalinity that needs to be consumed.

The pH may drop as far as Bru’n Water indicates, but I sort of doubt it.  The former version of Bru’n Water had a limit on how negative the RA could go and still affect mash pH.  That is because Kai performed experiments that prove that the mash pH will never fall below about 5.1 by adding hardness to the water.  In other words, a highly negative RA will NEVER cause the mash pH to fall below 5.  Now, this doesn’t mean that a brewer can’t get the mash pH to drop below 5 if they are using acid to reduce pH.

I took out the negative RA limit in the current version of Bru’n Water, but you should never be purposely aiming for a pH below 5.3 if you expect to produce good beer.  I have found the pH range of 5.3 to 5.5 (@ room temp) to truely be the range that produces good beer.  Aim for 5.3 if your style would benefit from being sharper and crisper or 5.5 if the style would benefit from being fuller and rounder.

The bottom line here is to forget the acid malt in your case.  Its unneeded.  Recalculate the results with the acid malt deleted and brew it up.  Report back here with your mash pH results.  I’m expecting that both programs should be close to right.

Enjoy!

5

Thanks Martin,

OK, so why does Kaiser recommend using acid malt here http://braukaiser.com/wiki/index.php/Edel_Hell#Water and also here http://braukaiser.com/wiki/index.php/Various_water_recipes#Pilsner_water  Am I mis-interpreting his instructions as to what it means to “build my own water…”  for example his Pilsner water has no akalinity and an RA of -47 but he still suggests adding Sauermalz… you are saying that is wrong???

Looks like I have a lot of brewing to do, to really understand this all. Not a bad thing, right?

-red

6

They are both models and so are obviously not perfectly accurate. That said, Weyermann Pils, -47 RA and 2% Weyermann acid malt are about how I brew Pilsner and the last one came in at 5.3X and so I think that Kai’s looks closer to what I would expect.

7

I have a follow-up question related to the OP.  Please forgive me if this should be posted as a new topic.

How does the grist composition, in particular the amount of crystal/roast, factor in to the equation with these advanced tools?

In example, working out an Oktoberfest recipe that is 10.1 SRM with 93% malt (pilsner, munich, vienna) and 7% caramunich.  When I use John Palmer’s spreadsheet (version 3), I am getting a result that shows the overall profile to be more appropriate for a lighter colored wort than plugging the same amounts of salts/acids into Kai and Martin’s spreadsheets.  Is this because Kai and Martin’s spreadsheets are taking into account a different pH shift from the malt bill than just looking at the overall color of the resulting wort?

Here are the details:

Total Grist Weight 21 lbs

Total (strike + sparge) Water volume 16.5 Gallons

Tap Water:
Calcium 23PPM
Magnesium 5PPM
Sodium 10PPM
Chloride 23PPM
Sulfate 15PPM
Alkalinity as CaC03 = 73
Water pH is 8.7
Tap water treated with potasium metalbisulfite at 10mg/gallon and will be diluted with 50% RO Water.

Salts added to total volume of water = 5 grams of gypsum, 3 grams epsom salt, 6 grams calcium chloride and 3 ml of lactic acid.

John’s spreadsheet shows that the water profile will have a RA of -31 and would be appropriate for an SRM range from 3 - 8 (lower range than appropriate for my Oktoberfest at 10.1 SRM)

Kai’s spreadsheet gives a RA -34 but estimates mash pH at 5.3.

Is this because Kai’s spreadsheet more accurately reflects the lessened affect the grain bill will have on mash pH?  It would seem logical that more accuracy would be attained by inputing the percentage of roasted malt.

Last year, my Oktoberfest water profile had a RA higher, which was listed as appropriate for a SRM of 8 -12.  My overall impression was the beer tasted a bit too basic and the malt profile seemed a bit “confused.”  Just a guess, but I believe more acidity would have helped get a crisper and more appropriate malt profile.  I am leaning towards using Kai’s spreadsheet to further dial in the pH.

Any advice you fine gentlemen could offer?

8

Actually Kai’s model would predict a higher pH if the color were from roasted malt.

Palmer’s model assumes that each unit of SRM requires 9 units of RA or something close to that. The value of SRM → RA models is questionable but what is not questionable is that the slope in the Palmer model is high enough that his model is always worse than a model with a lower slope (like Kai’s).

9

I read back through the spreadsheet and Kai’s page on the subject and it seems that caramunich wouldn’t count as “roast” so I put the amount to 0% in the spreadsheet.  This changed the pH from 5.31 to 5.30.  Doesn’t seem like this has a huge effect.

Here is the link:

http://braukaiser.com/wiki/index.php/Beer_color,_alkalinity_and_mash_pH#Malt_color.2C_type_and_acidity

Does anyone mind double checking my calculations for this water?  Just want to make sure I’m on the right path using this new tool.  Here is a link to the file:

[www.treeofwoe.com/MASH/Kaiser_water_calculator - Oktoberfest 2.xls](http://www.treeofwoe.com/MASH/Kaiser_water_calculator - Oktoberfest 2.xls)

Here is the grist for reference:

38% Weyerman Bo Pils
31% Weyerman Munich Type II
23% Global Vienna Malt
8% Caramunich