Mash ph is consistently off: Is it me, or the calculator?

Discussion in 'Calculator Support Forum' started by AK Eric, Jun 30, 2020.

  1. AK Eric

    AK Eric New Member

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    I have:
    • A calibrated pH meter (reads accurate vs their calibration solutions)
    • Recent water report from Ward Labs
    Since I've gotten my pH meter and been tracking this, I'm finding that if I add the salts/acids that BF recommends, the final pH is never even close to what the calculator says: Sometimes high, sometimes low, never close.

    Without getting into too much detail (and I can if needed), I'm trying to wrap my head around if I'm doing something wrong, or if it's the software.

    For example, I recently brewed a Kornøl-esque beer.
    15lbs Bonlander Munich
    1lb Caramel Munich 60L
    1.5lb cherywood smoked malt

    The calculator said, without any additions, the pH should be 5.42: A nice number. But I added .75tsp Gyspum and Calcium Chloride to help get my salts in better ranges vs the 'balanced profile' and my water report. And even then, they (according to the calculator) should only lower the pH by .068 total (not much). No acid this time, since the calculated pH was right around 5.3ish with the salts.

    Since i do BIAB, I added my 6.9g of water to the HLT, then added the salts while it headed to strike temp.

    20 minutes into the Mash, taking a pH sample, it was reading 4.96. This has been pretty consistent with other beers as well. It's like the calculator reports the pH is way higher than it really is, so I add salts\acids to lower it, and it ends up coming int way low. When I've done tests with 'late additions' of salts\acids to the mash (to try and correct it, even though it's probably too late based on the fully modified malts doing their conversion fast), it's roughly 2x what the calculator says they should do.

    I know this isn't a lot to go on other than hearsay, but I'd appreciate any suggestions \ thoughts anyone has, thanks.
     
  2. okoncentrerad

    okoncentrerad Active Member

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    I'm far from knowledgeable at this but...

    I've found that pH meters need constantly calibration... do you calibrate before every brew session?

    Do you measure pH when wort is at room temperature?

    Do you check the pH of the water before mash?
     
  3. Semper Sitientem

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    I’ve found the ph meters are very needy instruments that require a lot of attention. Aside from what @okoncentrerad stated, you are supposed to store the electrode in a buffering solution when not in use and there’s also a cleaning solution. Also, if you have one of the lower cost meters, they only have an accuracy lifespan of about 12-18 months.

    I use the water calculator and add the recommended additions, but I’ve given up on constantly measuring ph because I don’t want to go through the proper meter maintenance routine. My beer tastes good and that’s what’s important.
     
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  4. Yooper

    Yooper Administrator
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    It would be tough to get a mash pH of 4.96 without adding quite a bit of acid, even starting with distilled water. Maybe check the calibration of your member with the calibration solutions after such a weird reading.

    Also, do you have the water calc set up with the current full mash volume? Are you using extremely soft water?
     
  5. AK Eric

    AK Eric New Member

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    Thanks everyone, some more info based on your questions:
    • I calibrate every few months: Maybe I should do this before each brew.
    • I chill the wort to room temp before reading (well, mid-70's, meter is calibrated to 68 I think)
    • Water pH : I've been told this has no bearing on mash pH (John Palmer, many other sources), but i don't check it. However, considering I have a water report, maybe I should, just to see how close my meter reads to it (presuming my water pH hasn't changed).
    • I store it moist, with the buffering solution. I clean it with distilled water before every use.
    • It's less than 18 months old, but I should consider getting a new tip based on this feedback.
    • I sometimes I mash with full volume (BIAB), sometimes I sparge, sometimes I combine the waters, sometimes I don't, but I always take that in account when setting up my water profile per brew session.
    • I'm in the SF Bay Area, we get our water piped in from the Sierra Nevada's: I'd call it 'pretty normal water' : not 'super soft', but not remotely hard.
    Again, thanks for the thoughts.
     
  6. Yooper

    Yooper Administrator
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    Water pH DOES change. For example, RO water may come out at neutral, but within a few minutes absorb c02 from the air, and have a low pH as a result.
    A freshly calibrated and accurate meter is essential. It should be calibrated each brew day and checked for drift.
     
  7. Nosybear

    Nosybear Well-Known Member

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    Water changes, particularly municipal supplies, malt changes.... Nothing will ever predict exactly. Meters can be mis-calibrated. Best approach at our scale is take the close-enough perspective: If it's in a usable range, say 5.2-5.6, go with it. You can dial it in as your repeatability becomes better but at the start, that range is good enough. If it's in there, brew it.
     
  8. AK Eric

    AK Eric New Member

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    Yah, I realize that everything changes :) It's just my results have been so far off literally every time. That being said, like above, I'll start pre-calibrating it before each new brew and see if it gives results closer to the calculator.

    Thanks everyone.
     
  9. Yooper

    Yooper Administrator
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    I can look at your water report to be sure, but if you're getting a pH of below 5.1 or so without adding lots of acid, the meter is suspect.
     
  10. AK Eric

    AK Eric New Member

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    Thanks @Yooper , find attached.

    I re-calibrated my meter last night: I was probably .2 points off from the solution, not good, drift for sure. Live and learn! :)
    waterReport.JPG
     
  11. Yooper

    Yooper Administrator
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    I didn't work it out, but with a bicarb level of 82, you have plenty of alkalinity to NOT have such a low mash pH even if you're making a stout with a good percentage of roasted malt. If you have a very very thin mash, and a ton of black malts, it's possible that it could drop to below 5.2, though.
     

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