Do These Water Additions Look Alright?

[Tpost704]

I am preparing for my first BIAB batch and was hoping for some input. I provided the recipe below, it is Biermuncher's Centennial Blonde. I will be mashing and dunk sparking with RO water. I am using Brew'n Water with the "Yellow Full" water profile as my target. Based on Brew'n Water, if i add 0.35 grams/gallon of calcium chloride, 0.35 grams/gallon of gypsom, and 0.5 ml/gallon of lactic acid to 3.5 gallons of RO water in combination with my grain bill, my estimated mash ph will be 5.29. I was going to mash for 1 hour at 150 and then dunk sparge in 3.5 gallons plain RO water. I am also toying with the idea of adding an additional 0.35 grams/gallon of calcium chloride, 0.35 grams/gallon of gypsom to the brew kettle as to not dilute my target water profile. Does this sound like a decent approach to this brew or are there other additions/tweaks you would recommend. As always, thanks for the input. Cheers!



****5 Gallon Batch****

Batch Size: 5.50 gal
Boil Size: 7.0 gal
Estimated OG: 1.040 SG
Estimated Color: 3.9 SRM
Estimated IBU: 21.5 IBU
Brewhouse Efficiency: 70.0 %
Boil Time: 60 Minutes

Ingredients:
------------
Amount
7.00 lb Pale Malt (2 Row) US (2.0 SRM)
0.75 lb Cara-Pils/Dextrine (2.0 SRM)
0.50 lb Caramel/Crystal Malt - 10L (10.0 SRM)
0.50 lb Vienna Malt (3.5 SRM)
0.25 oz Centennial [9.50%] (55 min)
0.25 oz Centennial [9.50%] (35 min)
0.25 oz Cascade [7.80%] (20 min)
0.25 oz Cascade [7.80%] (5 min)
1 Pkgs Nottingham (Danstar #-) (Hydrated)


Mash at 150 degrees for 60 minutes.

 

[mabrungard]

Those additions look appropriate for the pale grist that you'll be mashing. Bru'n Water should get you in the ball park for pH. Do be sure to check your RO water source with a TDS meter to assure that it's as pure as you're assuming in Bru'n Water.

 

[ajdelange]

if i add 0.35 grams/gallon of calcium chloride, 0.35 grams/gallon of gypsom,

The standard recommendation is about a half gram per gallon if you are using both and as my personal feeling is that less is better I think you will be good at 0.35 each.

and 0.5 ml/gallon of lactic acid to 3.5 gallons of RO water in combination with my grain bill, my estimated mash ph will be 5.29

That seems a bit low for a target pH. 5.4 - 5.5 is more reasonable. Splitting the difference to 5.45 you are going to need about 28 mEq protons to get that mash (caveat - unless I have detailed titration data on the particular malts you are using I can only come up with an approximate answer by doing the calculations based on similar malts) to 5.45. At pH 5.45 88% lactic acid releases 11.5 mEq/mL so you will need 28/11.5 = 2.4 mL.

If you insist on pH 5.29 the proton requirement more than doubles to 59.7 and you would need 59.7/11.5 = 5.2 mL.

With no acid added the mash pH will be somewhat below the base malt DI pH because the cramel malts are acidic relative to the base malt. I'm estimating it will fall around pH 6.

The 1.75 mL you propose would give you about 20 mEq and that should land you around pH 5.5 which isn't a bad place to be.

As always I recommend a test mash if at all possible.[/QUOTE][/QUOTE]