Calculating water adjustments for cereal mash.

[Bennypapa]

I'm planning to brew a Kentucky common using a traditional cereal mash of 6 row and degermed corn grits. I'm wondering how I should calculate my water adjustments.

Should I use the whole recipe or make separate calculations for each mash?

The whole grain bill for a 10 gal batch is
60% 6 row malt. 11 lbs
36% Grits. 6.5 lbs
2.7% Black malt. 0.5 lbs
1.4% Caramel 60. 0.25 lbs

Cereal mash
6 row malt. 2.5 lbs
Grits. 6.5 lbs

Malt mash
6 row malt. 8.5 lbs
Black malt. 0.5 lbs
Caramel 60. 0.25 lbs
Add cereal mash after mash, gelatenization boil

I calculated my water adjustments for the whole recipe using Brunwater.

Existing water
Ph 7.8
Ca 41.4
Mg. 9.9
Na 22.3
Sulfate 55
Chloride 30
Bicarb 110
Cations 3.8
Anions 3.8
Total hard. 144
Alk 91
RA 56

Adjustments
0.17 grams/gal Gypsum
0.13 grams/gal. Calcium chloride

Resulting adjusted water
Ca 60.8
Mg 9.9
Na 22.3
Sulfate 80.1
Chloride 45.9
Bicarb 110.2
Cations4.8
Anions4.8
Total hard.193
Alk 91
RA 42
Mash ph 5.2
So,
Should I treat the whole volume of mash water our should I calculate and treat the cereal and malt mash water separately?

 

[mabrungard]

Hmm? I find that flaked grains won't affect mash pH too much. But that is probably because I typically don't use a lot of them in a grist. However, that is a lot of corn grits and I have no idea how that reacts with respect to mash pH. Hopefully you have a pH meter to help guide you in this uncharted territory.

With regard to how to handle each step, I guess you could calculate the effect of each mashing step. That might be important since there is a fair portion of black and crystal malt in the final mash and none in the cereal mash. I have to believe that the cereal mash would end up with a somewhat high pH as its set now. The good thing is that there isn't much husk tannin to extract out of that cereal mash. I would still consider that the cereal mash might be less problematic with a more typical pH of around 5.4.

 

[Bennypapa]

When calculated individually I get

Cereal mash PH 4.5

Malt mash PH 5.7


BUT, I can't find any reliable info about the PH affects of corn grits.
As is, I have it entered as a base malt but I don't know if that is accurate.

 

[mabrungard]

When calculated individually I get

Cereal mash PH 4.5

Malt mash PH 5.7

How did you calculate a pH of 4.5?? There is NO way that the pH could drop to that level with corn and 6-row.

 

[Bennypapa]

I got that using Brunwater (though it's entirely possible I typo d something.)
I don't have it with me now. I'll review and post later. Likely I'm using it wrong.

 

[Bennypapa]

OK, I checked and I got ph of 4.8 for the cereal mash of
3.5 gals water
6.5lbs grits
2.5 lbs 6row malt

I used base malt as the grain type for the grits. Not sure that's right though. As you know there isn't an option for adjunct in that drop down

 

[Bennypapa]

I trashed that try and started over.

I had something wrong obviously. Now Getting mash PH of 5.9 for the cereal mash.

 

[mabrungard]

That does sound more reasonable. Pale malt mashed in pure distilled water will typically have a pH of about 5.7 to 5.8. I am assuming that the corn in that cereal mash would produce a similar result.

 

[Bennypapa]

Excellent, Thank you.

Those of us without formal education in these realms appreciate all your help.