First Use of my new pH Meter.. hopefully I did it right.

[Mirilis]

Hey guys, I just did a double batch today and I used my Omega PH meter for the first time. Hopefully I did it right . Let me know if you guys think these numbers are right.

I had to add some lactic acid and CaCl in the water before i started. I made an american lager, and a doppelbock. I took a pH reading (after I calibrated it) at 15 minutes into the mash and another at 45 minutes into the mash. Here is what I got.

Doppelbock: 15 minutes ( 5.24 pH, 21.3 degrees C), 45 min ( 5.26 pH, 19.6 Celcius)

American Lager: 15 minutes ( 5.38 pH, 20 Celcius ), and 45 min ( 5.47, 18.2 Celcius)

I used Bru'nWater for my additions calculations. It said I sould have ended up in the 5.4ish range so it was closer with the 2nd beer than the first..

 

[mchrispen]

That's pretty good result for first time out. Gratz!

I tend to measure at 30 and 45 minutes. On my system, stability of the mash seems to occur somewhere in the middle for most beers.

Take a hard look at the Lovibond ratings for your malts in BWS. That, plus very careful volume management, should help you tighten up your mash pH estimates.

 

[ajdelange]

Have you done the stability check on this meter yet? Be interested to see how it fairs.

 

[Mirilis]

When I calibrated it actually calibrated quicker than I expected and gave me 96% .. I guess between 70-115 is good so at least the electrodes not old or anything

 

[ajdelange]

I was asking about the stabilty test (https://www.homebrewtalk.com/showthread.php?t=189405#post2201989). I assume that you are reporting the slope number that you got back from the calibration. You would hope that a new electrode would give you something closer to 100% but yes, 96% is OK. Write that down (and write down the offset too) each time you calibrate. You can monitor the aging of your electrode that way.

Martin had suggested in another thread that the meter manufacturers intentionally rip you off by recommending that you use a storage solution that will deplete your electrode's fill faster than normal. That's pretty much nonsense but what some do in fact do is to set their calibration firmware to refuse to accept a cal where the slope is under 95% (fix: switch the mode to mV, calculate your own slope and offset and compute pH from mV yourself using the parameters you calculated). I think electrodes are quite useable down to at least 90% and perhaps even lower than that if their response times are reasonable. Where did you get the 70% number? Which Omega meter is this? I'm also curious as to how one could ever see a slope of greater than 100%. OK, I have seen 100.2 or 100.5% on a couple of occasions at which point I do a recal and usually get 98 or so. I can see how an electrode can exhibit poorer slope than Nernstian but better than Nernstian by 15%?

 

[Mirilis]

pH Manual

theres the link to the manual for mine.. it says between 70-130% slope.. i thought that sounded odd but then again im just learning to use this thing now.