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General Category => All Grain Brewing => Topic started by: quattlebaum on October 20, 2013, 02:29:56 PM

Title: Why does my PH fluctuate so much?
Post by: quattlebaum on October 20, 2013, 02:29:56 PM
I have been reading Palmer and Kaminski water book and am trying to wrap my head around it. My recent batch just confuses me. I know this is complicated but i would just like to be close to my predicted PH when i mash. I assume that its something to do with the Effective Alkalinity and Residual Alkalinity and the buffering capacity? I test my grain Distilled water PH and make necessary adjustments in EZ water along with using a proper PH meter with 2 pt calibration and room temp measurement.  This is my latest batch. Any suggestions on why my PH is way off.

Recipe: Recreational Real Ale   TYPE: All Grain
Style: Specialty Beer
---RECIPE SPECIFICATIONS-----------------------------------------------
SRM: 21.1 SRM      SRM RANGE: 5.0-50.0 SRM
IBU: 30.2 IBUs Tinseth   IBU RANGE: 5.0-70.0 IBUs
OG: 1.045 SG      OG RANGE: 1.030-1.110 SG
FG: 1.015 SG      FG RANGE: 1.006-1.024 SG
BU:GU: 0.666      Calories: 151.6 kcal/12oz   Est ABV: 4.0 %      
EE%: 75.00 %   Batch: 3.00 gal      Boil: 4.27 gal   BT: 65 Mins

Starting Water (ppm):         
Ca:   66      
Mg:   20      
Na:   27      
Cl:   18      
SO4:   36      
HCO3:   262      

Mash / Sparge Vol (gal):   2.13   /   2.64
RO or distilled %:   25%   /   25%
Total Grain (lb):   4.9      

Adjustments (grams) Mash / Boil Kettle:         
CaSO4:   0.4   /   0.495774648
CaCl2:   1.2   /   1.487323944
MgSO4:   0   /   0
NaHCO3:   0   /   0
CaCO3:   0   /   0
Lactic Acid (ml):   0.2            

Mash Water / Total water (ppm):         
Ca:   101   /   101
Mg:   15   /   15
Na:   20   /   20
Cl:   85   /   85
SO4:   55   /   55
Cl to SO4 Ratio:   1.56   /   1.56
Alkalinity (CaCO3):   132   
RA:   51   
Estimated pH:   5.69   My actual PH was 5.31 at 15 min
(room temp)            

Total Grain Weight: 4 lbs 13.7 oz   Total Hops: 0.75 oz oz.

Amt                   Name                                     Type          #        %/IBU         
4 lbs 1.4 oz          Pale Malt, Maris Otter (3.0 SRM)         Grain         1        84.2 %       
8.2 oz                Crystal, Medium (Simpsons) (55.0 SRM)    Grain         2        10.5 %       
4.1 oz                Carafa II (412.0 SRM)                    Grain         3        5.3 %         

Name              Description                             Step Temperat Step Time     
Mash In           Add 2.13 gal of water at 169.2 F        154.0 F       60 min       

Fly sparge with 2.73 gal water at 168.0 F

---BOIL PROCESS-----------------------------
Est Pre_Boil Gravity: 1.033 SG   Est OG: 1.045 SG
Amt                   Name                                     Type          #        %/IBU         
0.25 oz               Warrior [16.70 %] - Boil 60.0 min        Hop           4        30.2 IBUs     

Amt                   Name                                     Type          #        %/IBU         
0.50 oz               Citra [13.00 %] - Aroma Steep 0.0 min    Hop           5        0.0 IBUs     

Title: Re: Why does my PH fluctuate so much?
Post by: a10t2 on October 20, 2013, 02:48:50 PM
5.3 is a normal mash pH. Maybe a tenth or two lower than you'd want for most beers.

So next time you're brewing something fairly dark (5% Carafa is quite a bit), you could add a little alkalinity to the mash, or just not add the calcium salts, or not dilute, and you should be able to bump it up a bit.

I don't think you're doing your RA calculation correctly:

Code: [Select]
RA = TA - 0.71[Ca] - 0.59[Mg] = [HCO3]/1.22 - 0.71[Ca] - 0.59[Mg]
I get 156 (as ppm CaCO3) for the base water and 80 for the mash water as posted.

Edit: FWIW, I downloaded the EZ spreadsheet and it does calculate the RA correctly, so you may have an input error somewhere.
Title: Re: Why does my PH fluctuate so much?
Post by: quattlebaum on October 20, 2013, 03:10:17 PM
I suppose i am depending on an online calculator to aid in determining my PH, EZ water and there can be calculations that are wrong. I think in should lean how to do them manually like you have and it may help me understanding a bit more.   Also i though 5% Carfa was a bit much also i have never used that much. This is for a cask ale and found it in an old beer advocate mag. Thanks 
Title: Re: Why does my PH fluctuate so much?
Post by: hopfenundmalz on October 20, 2013, 05:37:09 PM
You could always mash without the Carafa and cold steep it separately. Add the cold steep at the end of the mash. That way you mash will stay higher.