OG and ph

Discussion in 'General Brewing Discussions' started by CaptAwol, Mar 17, 2019.

  1. CaptAwol

    CaptAwol New Member

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    I've just managed to completely pickle my head!
    In previous brews of light blonde ales, I've aimed at and succeeded to treat my water to get a target pH of 5.2 to 5.4, this is measured from a sample taken about 15 min into the mash, but my target OG has always fallen sort by about 5, ie 1.033 for 1.038.
    On my latest brew I didn't bother treating the water but used pH stabiliser, pH was 5.8 and the target OG was achieved!
    Now I'm totally confused and comments welcome
     
  2. Nosybear

    Nosybear Well-Known Member

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    Strictly based on my experience, I get better conversion at recommended pH. I don't know much about pH stabilizers, I use salts and acid to adjust pH. I don't use them because I don't know what's in them. But in cases like this, I always look at measurement error first, then other potential causes. And don't put too much weight on the one observation, next batch may be completely different.
     
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  3. Hogarthe

    Hogarthe Well-Known Member

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    5.8 isn't that far off what's recommended. It could be your ph measurements have been off and this batch was the one that was actually in range. Or maybe you mashed longer,or at a different temp and that helped your efficiency?
     
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  4. Mase

    Mase Well-Known Member

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    Novice myself, but the two things may not be related.
     
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  5. BOB357

    BOB357 Well-Known Member

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    I'd be more inclined to believe the difference was due to a variable other than pH. Maybe a small difference in the grain bill, crush, mash temperature or duration, calcium level, or any combination of these and any I may have missed. 3 points is what many would consider within their margin of error, so I wouldn't rack my brain trying to figure out why.
     
  6. Craigerrr

    Craigerrr Well-Known Member

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    When I first read your post, I didn't feel like I was experienced enough that I could have posted my thoughts. My first thought however was that there are a number of other variables other than the pH of the mash that could/would affect your gravity readings like Bob and others have noted above. Happy Brewing!
     
  7. Nosybear

    Nosybear Well-Known Member

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    All of the above are correct. Regardless of the path you take to correct, correct one thing at a time. That's the only way you'll know what worked.
     
  8. BOB357

    BOB357 Well-Known Member

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    Nosy knows. Pun intended. Great advice. Always change one thing at a time so you know what made the difference.
     
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  9. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    A pH of 5.8 favors the alpha enzymes that is most active above 150F. If you want a better conversion at a lower temperature then a lower pH will work better as it favors beta enzymes, 5.0-5.2 (at mash temperatures). Remember when pH is taken at room temperature, (for the sake of the pH probe) it will be .2-.3 points lower at mash temperature. So a pH of 5.2 at room temperature is more like 4.9-5.0 at mash temperatures.
     
  10. Trialben

    Trialben Well-Known Member

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    According to braukaisers mash ph experiments 5.6 ph yielded the best extraction closer to your 5.8ph maybe has something to do with it.
     
  11. Nosybear

    Nosybear Well-Known Member

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    I can't find agreement in the brewing world on whether pH should be measured cold or hot so I go with the chemical world: Measure at room temperature. Given the range of pH readings, sticking with 5.4 would keep me in the range even if I should be measuring hot (dropping pH by 0.2). But I've done beers at higher pH's and not gotten the variation the OP did, so I'd suggest something else is the problem.
     
  12. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    The main reason mash pH is measured at room temperature is because the typical single/dual junction pH meters probe life is shortened. You could measure it at higher temperatures, but it's tough on probes. I checked it once at 145F and compared it to the pH at 80F and found the higher temperature was .2 lower than at 80F. Bruakaiser claims it's up to .35 pH drop.

    If you measure it at room temperature, you just have to subtract .2 from the reading. As the temperature rises, there are more free ions and the pH actually drops as temperature rises. When I finish the boil and chill the wort, I shoot for 5.2 at pitching temperature.

    If you are measuring with Ph litmus paper, temperature doesn't seem to matter.

    Here's is Braukaiser's article on the subject:

    http://braukaiser.com/blog/blog/2011/03/02/about-ph-targets-and-temperature/
     
  13. thehaze

    thehaze Active Member

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    #13 thehaze, Mar 22, 2019
    Last edited: Mar 22, 2019
    Your OG had nothing to do with the pH. As long as pH is in range, your beer will turn out well, which is the most important thing.

    I usually target a mash pH between 5 and 5.3 for all beer styles. I haven't noticed any variations in efficiency, that would correlate with the pH of the mash. There is however strong correlation with grain crush, sparge times, etc.
     
  14. Brewing With E's

    Brewing With E's New Member

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    Hey, I have a question on this. Not questioning the fact that the pH is lower at a higher temp, but wouldn't the recommended or target pH (say 5.2) also be referenced at room temp?

    For example, if I'm aiming for a mash pH of 5.2, doesn't that mean a mash pH of 5.2 at room temp? Therefore I would compare my sample reading at room temp? Or are target pH's typically referenced at mash temp? (i.e. 5.2 at 154F)? I never see a temperature referenced with target pH, so my assumption would be it is at reference temp (room temp).

    Just askin'.
     
  15. CaptAwol

    CaptAwol New Member

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    Thanks for all replies and info, I'm now closely checking everything as it's to easy to blame one thing for another.
    I did another brew with just treating the water with ph stabiliser which again had a ph5.8 as always taken at room temperature from a sample 10 min into mash, this brew came up short on the OG of .006! Obviously I realise now that something else is wrong. I do measure my samples with 2 or more equipment.
    Much to my despair when slowly emptying the spent mash grain I found a large 'doh ball', this puzzled me a bit as I always underlet and stir the grain after never having this problem before.
    Anyway I've done another brew without ph stabliser, just treating my water as I've done previously as per calculation, adding Gypsum and lactic acid as required. This came back with a ph of 5.2 as targeted and OG of brew was spot on.
    I don't know why I got fixated with the ph or how I've allowed 'doh balls' in the mash, complacency perhaps!
     
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  16. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    #16 HighVoltageMan!, Apr 8, 2019
    Last edited: Apr 8, 2019
    Sorry for being so late in responding. pH is higher at room temp. For example a pH reading of 5.6 at 80F may be 5.3-5.4 at 154F due to more free ions at a higher temperature. It’s commonly known among brewers but often not communicated well. If you you use litmus strip it doesn’t seem to matter as far as temperature of sample. The pH readings do change with temperature, I have verified that myself.
     
  17. Nosybear

    Nosybear Well-Known Member

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    Best bet is to take all samples at room temperature. Better for your pH meter's electrode and more consistent. That may be why there is so much disagreement over temperature ranges because few brewing publications or writers bother to mention what temperature the pH is taken at. Shoot for 5.4 at room temperature and it's really hard to go wrong.
     
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  18. thehaze

    thehaze Active Member

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    I agree with Nosybear. All pH readings must be taken at room temperature or as close to 68F as you can.
     
  19. Nosybear

    Nosybear Well-Known Member

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    Neighborhood of 68 degrees F is okay. High precision isn't required.
     
  20. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    The pH can be taken at any temperature lower than 100F for the sake of the probe. For consistency, it should be taken at a given temperature and I measure at 80F. The difference in pH from 80 to 68F is really not very much, at lower temperatures the pH changes less over a given range. The important thing to know is that it's higher at room temperature compare to mash temps.
     

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