Mash pH Help Needed

[disney7]

So, my water is pretty soft:

Total Dissolved Solids (TDS) Est, ppm 51
ppm
Sodium, Na 8
Potassium, K < 1
Calcium, Ca 6
Magnesium, Mg 1
Total Hardness, CaCO3 19
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 1
Chloride, Cl 7
Carbonate, CO3 < 1
Bicarbonate, HCO3 16
Total Alkalinity, CaCO3 13

I normally acidify my water to a pH of 5.5 with phosphoric acid and only mash the grains that need to be mashed. The crystal and roast go in at the very end of the mash and get recirculated for twenty minutes or so. This has always given me a nice pH of 5.3 during the conversion.

This time I have an AG kit. The crystal and roast malts are mixed in with others (Victory) that need to be mashed (as far as I can tell), so I will need to alter my usual process.

The grain bill is:

8 lbs 13.2 oz         Pale Malt, Maris Otter (3.0 SRM)         Grain         2        72.7 %        
1 lbs 1.6 oz          Munich Malt - 20L (20.0 SRM)             Grain         3        9.1 %         
15.4 oz               Caramel/Crystal Malt - 40L (40.0 SRM)    Grain         4        8.0 %         
8.8 oz                Caramel/Crystal Malt -120L (120.0 SRM)   Grain         5        4.5 %         
8.8 oz                Victory Malt (25.0 SRM)                  Grain         6        4.5 %         
2.2 oz                Pale Chocolate (200.0 SRM)               Grain         7        1.1 %

Any suggestions on water additions? From Bru'n Water it looks like my mash pH will be too low (acidic) at around 5.1 even if I make no water additions at all. Should I add a tsp of Baking Soda to bring it up to 5.3? That will give me about 50 ppm total of Sodium. Will that be noticeable?

How about any CaCl2 or Gypsum in the boil? (Adding these to the mash would lower/acidify the mash pH even more). Normally for a recipe like this I would throw a tsp of CaCl2 in the mash.

Also, I've had some confusion on whether Victory needs to be mashed. Some people are telling me no, but a couple of online sources say yes.

Thanks for any input.

 

[ajdelange]

I normally acidify my water to a pH of 5.5 with phosphoric acid...

No need to do that as its alkalinity is so low.

...and only mash the grains that need to be mashed.

All grains need to be mashed (recognizing that some people don't like to do this for the black malts).


The grain bill is:

8 lbs 13.2 oz         Pale Malt, Maris Otter (3.0 SRM)         Grain         2        72.7 %        
1 lbs 1.6 oz          Munich Malt - 20L (20.0 SRM)             Grain         3        9.1 %         
15.4 oz               Caramel/Crystal Malt - 40L (40.0 SRM)    Grain         4        8.0 %         
8.8 oz                Caramel/Crystal Malt -120L (120.0 SRM)   Grain         5        4.5 %         
8.8 oz                Victory Malt (25.0 SRM)                  Grain         6        4.5 %         
2.2 oz                Pale Chocolate (200.0 SRM)               Grain         7        1.1 %

Any suggestions on water additions?

You might want to add a bit of calcium chloride to get chloride up to 20 mg/L or so and, if you like the effects of sulfate from gypsum.

From Bru'n Water it looks like my mash pH will be too low (acidic) at around 5.1 even if I make no water additions at all. Should I add a tsp of Baking Soda to bring it up to 5.3?

Probably not. I can't say exactly what your mash pH will be because I don't know the details of each of the grains but indications are, using data on similar malts, that it will be around 5.4 (I included enough phophoric acid to 0 the small proton deficit of the water and assumed 1.5 qts/lb).

How about any CaCl2 or Gypsum in the boil? (Adding these to the mash would lower/acidify the mash pH even more).

Yes, but not by much. Increasing calcium by 100 mg/L would probably only lower mash pH by 0.1 (to around 5.3)

Normally for a recipe like this I would throw a tsp of CaCl2 in the mash.

That should be fine and a good idea.

 

[disney7]

So, it sounds like the condensed answer is to just skip the Phosphoric acid addition and go ahead and throw 1 tsp of CaCl2 into the mash?

I'm a little confused though. For the last ten or so brews that I've done, I started acidifying the strike water to 5.5 (from 7.5) and only mashing the base grains with a tsp of CaCl2 and/or gypsum. Checking the pH with a meter, that has had me hitting 5.3 or 5.4 every time. I then throw the pre-converted malts, crystal and roast, in at the end and recirc for twenty minutes or so. I would have thought that following the same process, but putting the crystal and roast in at the beginning would have to drive the mash pH down several points. What am I missing there?

Thanks (still trying to figure this water thing out)

 

[ajdelange]

The table below (I didn't know you could do this!) may help you understand what is happening. The numbers are all based on 'similar' malts and the assumption that the mash pH will wind up at 5.43. The proton deficits column lists the number of mEq of protons that must be added to a mash component to bring its pH to 5.43. The pH shift column gives a rough idea of how much the pH would shift if you took an item out but this has to be taken with a grain of salt. As you can see with respect to the water its proton deficit with the phosphoric acid added is pretty much 0 and the proton deficit for all 4.5 gallons attributable to the alkalinity is small at 3.46 mEq. The long poles in the tent are the Maris otter and the Caramel. The MO has as much proton deficit requirement as the sum of all the other malts. As the pH shift numbers show the increments from the dark malts are not that significant. If yoy held them out (but I can't imagine why you would) pH would probably be about 0.1 pH h higher.

Item                     Proton Deficit    pH Shift
Water Alkalinity             3.46           -0.0134
Water Calcium               -0.58            0.002
Water Itself                 0.54           -0.002
Phosphoric Acid             -3.46            0.0134

Maris Otter                 34.32           -0.13
Munich                       0.19           -0.001
Caramel 40 L               -21.12            0.08
Caramel 120 L               -8.19            0.032
Victory                     -1.53            0.006
Chocolate                   -3.58            0.014

Given that you have a pH meter you should use any of these predictions as nothing more than a broad guideline. Make a test mash and check its pH. If it is too low (unlikely) add bicarbonate until the pH is proper. Then scale that amount of bicarbonate to the full brew length and add it to the mash water.