Mash pH estimate in BF always low

Discussion in 'Calculator Support Forum' started by Bracken, Jun 3, 2019.

  1. Bracken

    Bracken New Member

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    I use RO water. I had it tested by Ward Labs. All stats are configured in my BF settings. My estimated mash pH in Brewer’s Friend consistently comes out lower than actual. My meter is two-point calibrated in known solutions. 6 brews in a row my estimate is off between .15 and .20. For example, today’s brew was planned for 5.3 pH - using brewing salts and lactic acid. Actual mash pH was 5.46. Any suggestions to get closer to target (other than overshooting acid additions)?
     
  2. Yooper

    Yooper Administrator
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    Hmmmm, I wonder if the water is a bit higher in alkalinity currently than when tested, since the are all consistently lower than actual.
    Is it all sorts of beers, ie stouts, pale ales, blondes?
    I bought a super cheap aquarium tester that tests gH and kH (alkalinity, basically) and found that my RO water is currently 17 ppm. Still low, but much higher than the 0-2 ppm than I guessed!
     
  3. Bracken

    Bracken New Member

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    Yeah, that could be. I guess in theory if I slowly increase my HCO3 in my water profile, until I get close to my target mash pH), that should work. Correct?

    As for the styles, I haven't brewed a stout yet, but yes this is across styles.
     
  4. Nosybear

    Nosybear Well-Known Member

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    0.15 and 0.20 are really very close on the pH scale at that measurement. 17 ppm dissolved solids wouldn't make that big a difference in pH, though! There are a few things, as Yooper suggests, that could cause the deviation. Malts are variable. Water, even RO water, can be variable. I usually hit between +/-0.10 and that's close enough for homebrew.
     
  5. Yooper

    Yooper Administrator
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    It seems that would be a workaround, but I don't think that's really going to solve the pH prediction being so far off. I wonder if it's a malt thing- I know that Rahr malt has a DI mash pH of 5.5 while Briess is much higher, maybe something like 5.8, so if the recipe is using 'generic' US two-row, that could be a cause right there.
     
  6. Nosybear

    Nosybear Well-Known Member

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    Biggest takeaway is as long as you're between 5.2 and 5.6, it doesn't matter that much to conversion. If the beer tastes flat at packaging, you can always add some acid there.
     
  7. Yooper

    Yooper Administrator
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    One thing that I wonder about- are you clicking the box that says "salts in mash only", and using the salts just in the mash? Or something else?
     
  8. Bracken

    Bracken New Member

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    Yes, I'm clicking salts in mash only and I'm only using salts in the mash (no sparge).
     
  9. oliver

    oliver Well-Known Member

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    question tacking on to this, i'm seeing the opposite happen after a number of guys in a local club telling me they're all getting eg. 5.3 mash pH estimate from Brewer's Friend, but in reality their meters are reading much lower, around 5.0 or 5.1... So i tested myself, I have the orange BevDoctor pen which has been good, but taking a mash sample and testing the pH continually drifts lower than Brewer's Friend estimates. Is there something going on with the calculation? Or anyone else having simialr issues?

    more details i can provide from questions asked here: i always do full volume mash (no sparge) and calculate as such in the advanced water calculator. I put all the water in the mash and 0 in the sparge, and check the box that says salts added to mash only.

    I get all my water in the DeIonized machine at whole foods...which now i'm wondering if @Yooper and @Nosybear are on to something, is whole foods machine not truly a DI machine and has some residual minerals left in solution?

    also Yooper bringing up malt choices, i can get into detail on that but I'm not sure how to zone in on which malts could be the perpetrators?
     
  10. Yooper

    Yooper Administrator
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    Some malts have a lower DI mash pH- Rahr pale malt 2-row is one that jumps out to me as having a lower DI mash pH and I believe it is something like 5.5. So that's one but I don't know of others off-hand.

    Do you have a TDS meter? That's one way to check to see how the RO/DI machine is working. I have a very very cheap aquarium test kit (under $7) that measures general hardness (gH) and carbonate hardness (kH) and I use that to check my own RO machine.

    Can you check you pH meter in a known substance's pH? Like vinegar or something else? And when you say 'drift', are you saying that the pH meter continues to change?

    Once you check your pH of the cooled mash sample, sticking your meter back into the buffer should show no change in the reading of the buffer, and that's one way to check against drift.
     
  11. oliver

    oliver Well-Known Member

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    So i put my meter in pH 4 solution to calibrate, the numbers drop and drop and hover around 4, then i hit calibrate and it sets it self, then i rinse and put it in wort sample and the numbers start dropping close to ~5.2 but never stabilizes and keeps going down and down. certainly could be a faulty meter, but eventually it settles out somewhere in high 4s. I'll try testing it back and forth between wort and buffer solution. i'm mainly asking because I have 4 or 5 guys all say they have the same issue of pH showing much lower than Brewer's Friend prediction.

    I need to test the water machine I'm using to see how DI it really is.
     
  12. Nosybear

    Nosybear Well-Known Member

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    Are you thinking bad electrode? I get good estimates, within +/- 0.1 units, generally and that's using tap water. Calibration method isn't the same as mine but that shouldn't be an issue if he's following the manufacturer's process. Lots of variables in this problem....
     
  13. Yooper

    Yooper Administrator
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    Could be bad electrode, or pH meter drift.

    If the meter read 4.0 and 7.0 in the buffers, and then 4.95 in cooled wort, then 4.1 and 7.1 in the buffers, I'd say that it was an accurate reading.

    I've done that with my pH testing- got a reading that had me say "huh?" and then I rinsed with RO water, blotted, and put it in the buffer and it was way off so I had to recalibrate my meter.

    The other thing to keep in mind that the mash pH drops during the mash, so the reading should be taken within about 10 minutes into the mash at the latest.
     

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