Problem with Mash PH calculator

Discussion in 'Recipe Editor' started by Melee Brewing, Mar 21, 2021.

  1. Melee Brewing

    Melee Brewing New Member

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    Hi everyone. I've been using Brewer's Friend for a few years now and love it but I've run into a wonky issue with Mash Ph that I can't seem to understand. I have two water profiles saved in BF, one for distilled water at 8 ph and one for RO water at 5.6 ph. So, what confuses me is that when I switch between those two water sources in Brewer's friend, it doesn't change the predicted Mash ph. I have tried in the recipe editor and in the water calc section with linked recipe. Any thoughts? How can it be that the ph of the source water wouldn't have any impact on the mash ph?

    Any help would be appreciated.
     
  2. Sunfire96

    Sunfire96 Well-Known Member

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    Unfortunately, pH of the mash is not just a result of the pH of the water. Calcium and carbonate ions, alkalinity, and probably more things, all work together in the mash. It also has to do with how titratable, or buffered, your solution is.

    Here's a good series of articles to start with if you would like more info:
    https://www.brewersfriend.com/2017/11/19/brewing-water-basics-part-1/
     
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  3. Melee Brewing

    Melee Brewing New Member

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    Hello. Thanks for the reply. I have read through that article and a million others :) I get it that there are lots of factors that affect pH, but in this case there is only one variable. My two source water profiles are identical in every way (zeroes for all) except for pH with distilled set at 8 and my RO profile at 5.7.
     
  4. Nosybear

    Nosybear Well-Known Member

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    Love the avatar! I have some wonkiness too, now that I've switched to RO water. When I was using my tap water, the calculator worked fine, likely because of the buffers in the water (it had decent calcium and magnesium, great for amber beers!). With RO water, it becomes much more difficult to predict the mash pH. All that to explain the pH of the source water is unimportant to the mash pH. What's important is the amount of hardness and alkalinity, in other words, calcium and magnesium (hardness) and carbonate species (alkalinity). If, in the water calculator, the concentration of ions is similar, the pH will be the same. If you can find it somewhere, a quick read on residual alkalinity, the alkalinity left after the buffers in the malt and water have interacted, will explain it much better than I can.
     
  5. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    The pH of water is of very minimal significance, and with no buffering compounds, the pH of RO or distilled is even less important that that of water with minerals in it.

    It's not a great analogy, but you can kinda think of it like this. The pH is the temperature, and the buffering capacity (amount of minerals) is the mass. If you add a drop of water to the grain, it really doesn't matter whether it was as 40 degrees or 150 degrees, there's not enough mass (thermal capacity) for it to make a difference.
     
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  6. Nosybear

    Nosybear Well-Known Member

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    Since distilled water is generally pure of ions, it should have a pH of 7. But generally, it picks up some carbon dioxide from the air and becomes slightly acidic, I'm surprised yours is slightly alkaline. RO water is not devoid of ions, the filters generally remove around 90% of them, so it will have some slight hardness/alkalinity. But also, it is so low in ion concentration it can be treated as pure. But, exposed to air, it, too, will eventually become slightly acidic. This is as clear as I can make it: The pH of the water is of little concern when predicting mash pH. At/around 0 ppm total dissolved solids (distilled water), a tiny bit of anything can move the pH what seems to be a lot, the pH scale is logarithmic, remember, so a movement of 1 indicates a 10-fold change in water species. A tiny measurement error in a pH meter is huge when you're just off neutral. As I mentioned above, I notice problems using RO water, too. No buffers. But there's not much the calculator can do about that.
     
  7. Nosybear

    Nosybear Well-Known Member

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    Better analogy and you beat me to it.
     
  8. Silver_Is_Money

    Silver_Is_Money Active Member

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    If you leave fresh RO or distilled water (7.0 pH) open to the atmosphere for only a brief period of time the CO2 within the air will dissolve into it and soon reach an equilibrium (whereby dissolving into, and departing as a gas at the same rate) at about 5.8-5.9 pH.

    CO2 + H2O = H2CO3 (carbonic acid), and the reverse is H2CO3 = CO2 + H2O. And these two reactions are in equilibrium at ~5.8-5.9 pH.

    It takes incredibly little acid (CO2 + H2O) to move water from neutral to pH 5.8-5.9. The buffering capacity of "pure" water is nill. Buffering Capacity is the measure of resistance to change in pH. If there is no buffering capaciy there is no resistance to change in pH.

    Short version: Distilled and good RO will not move the pH of a mash regardless of the initial water pH. Both of these waters get dwarfed by the buffering capacity of the combined grist and added minerals. RDWHAHB
     
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  9. Melee Brewing

    Melee Brewing New Member

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    Thank you everyone.
     
  10. Craigerrr

    Craigerrr Well-Known Member

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    Cheers!
     
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