Strike Water pH vs Sparge water pH

I am trying to pay close attention to my mash pH when I brew this weekend. I am using Bru'n Water and my ward lab results to figure out how much lactic acid to add. Bru'n water separates the mash water acid addition from the sparge water addition and it wants a lower pH for the mash water compared to sparge water. Typically I heat the full volume of water needed for mash and sparge at one time. Should I be building my strike water separate from my sparge water? Hope that made sense..

thorHB said:

I am trying to pay close attention to my mash pH when I brew this weekend. I am using Bru'n Water and my ward lab results to figure out how much lactic acid to add. Bru'n water separates the mash water acid addition from the sparge water addition and it wants a lower pH for the mash water compared to sparge water. Typically I heat the full volume of water needed for mash and sparge at one time. Should I be building my strike water separate from my sparge water? Hope that made sense..

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No, you can treat all of your water at the same time.

You just want your sparge water to be under a pH of 6. So, you can always just add lactic or phosphoric acid to your sparge water after you mash in. Or add it just before sparging.

Yooper said:

No, you can treat all of your water at the same time.

You just want your sparge water to be under a pH of 6. So, you can always just add lactic or phosphoric acid to your sparge water after you mash in. Or add it just before sparging.

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Thanks Yooper. On the "adjustment summary" tab in Bru'n Water it wants 4.3 mL of lactic to 4.25 gal of mash water. 1.6 mL of lactic to 5.25 gal of sparge water. Seems like a big difference. Mash is about 1mL/gal and sparge 0.3mL/gal. Can you think of why the xls is set up this way?

thorHB said:

Thanks Yooper. On the "adjustment summary" tab in Bru'n Water it wants 4.3 mL of lactic to 4.25 gal of mash water. 1.6 mL of lactic to 5.25 gal of sparge water. Seems like a big difference. Mash is about 1mL/gal and sparge 0.3mL/gal. Can you think of why the xls is set up this way?

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Because you want your mash pH to be in the 5.3-5.5 range. The grains will bring it down some, but if your water is a bit alkaline you may need to add the acid.

Since your sparge water only needs to be at 6.0 pH or under, you don't need as much acid.

Yooper said:

Because you want your mash pH to be in the 5.3-5.5 range. The grains will bring it down some, but if your water is a bit alkaline you may need to add the acid.

Since your sparge water only needs to be at 6.0 pH or under, you don't need as much acid.

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Trying to wrap my head around this..

My tap water pH is 7.8. With the addition of 1mL/gallon of acid, my mash pH should be 5.2 according to Brun Water. Without the acid 5.7. Difference of 0.5 by adding 1mL/gallon (4.3mL/4.25gal).

For sparge acidification, starting pH is 7.8 with a desired 5.5. It is outputting a required 2.73mL liquid acid to 5.25 gallons of sparge water to achieve the desired 5.5 pH. Difference of 2.3.

How is it that 0.5mL/gal of acid in the sparge calc brings down the pH 2.3 points while 1mL/gal only brings down the mash pH 0.5 points?

Buffering.
There is more stuff in the mash, requiring more stuff to affect ph, compared to plain water.