Dilution of gypsum

[Jag75]

I use Bru N Water . I'm brewing a Wit and I was supposed to put .8g in the mash and .7g in my sparge . My normal practice is filling my Gf with the total water then pumping my sparge water into the pot . Then I add the gypsum , calcium chloride and lactic acid to each .

I forgot to pump the sparge water out and added .8g to the total 7.54 gallons of water . So my question is once I pump over the sparge water do I still have .8g in my mash and .8g in the sparge ? Does adding .8g into 7.54 gallons the same as adding .8g to 4.25 gallons?

 

[Silver_Is_Money]

Buffered chemical reactions and interactions between minerals and malts take place on a weight of present malts to weight of present minerals basis. Devoid of minerals, water that is effectively 'DI' is merely (for all practical purposes) a non participating reactants carrier. Even for the case of doubling the water volume the buffering of the grist alone (again, for all practical purposes) dwarfs the minimal buffering present within the DI water itself and thereby negates the otherwise fully expected ~0.3 pH point shift, resulting in so little pH shift due to the waters having been doubled as to be unmeasurable via an ordinary 0.01 pH precision meter.

As to the origin of the "fully expected" ~0.3 pH point shift for acidified DI water alone when doubled in volume:
Presume 7.00 pH DI water acidified to pH 5.4
It's molar concentration of H+ (acid) ions is now 10^-5.4 = 0.000003981 moles/L of H+ ions
Doubling the volume of the water halves the concentration of H+, so therefore 0.000003981÷2 = 0.000001991 moles/L of H+ ions
-log(0.000001991) = 5.7010378 pH
5.7010378 - 5.4 = 0.3010378 pH shift (or ~0.3 as "fully expected")

As to the case for the grist's buffering dwarfing the waters buffering go here:
https://www.homebrewtalk.com/thread...atter-for-mash-ph-adjustment-software.684443/

 

[Jag75]

Whoa ! Thanks for the reply Silver . So are you saying that I essentially have .4g in mash water and .4g in sparge ? Sorry in advance , I'm trying to grasp what your telling me .

 

[Silver_Is_Money]

I have it at 0.45 grams in the mash and 0.35 grams in the sparge, with the presumption that you mashed in 4.25 gallons. You wanted 1.5 grams total, with 0.8 grams in the mash and 0.7 grams in the sparge, so you came up quite short on both mash and sparge mineralization. Will it matter? No one can decide that but you. You will either like it more, or not notice any difference, or not like it as much.

 

[Jag75]

Ok got it ! Thank you very much . I ended up not brewing because the grain was full of weevils or grain mites .