General Category > Equipment and Software
How to use a pH meter
mabrungard:
--- Quote from: James Lorden on October 11, 2011, 12:31:34 PM ---Since the mash pH at room temperature should be higher then mash pH at mash temps do you know at what temperature level the common preferred mash pH levels are quoted.
--- End quote ---
AJ DeLange has wondered aloud the same question: What were the mash temps used when those old brewing text references cited mash pH? Neither of us know. I can only imagine that it would be in the saccharification range (140s to 150s F). Given that, the variation in pH within that range would be relatively small even if you assume the difference in room temp and mash temp pH was 0.35 units. (say 80F difference is to 0.35 units as 10F difference is to about 0.04 units). Pretty small.
punatic:
--- Quote from: mabrungard on October 11, 2011, 01:38:20 PM ---
--- Quote from: James Lorden on October 11, 2011, 12:31:34 PM ---Since the mash pH at room temperature should be higher then mash pH at mash temps do you know at what temperature level the common preferred mash pH levels are quoted.
--- End quote ---
AJ DeLange has wondered aloud the same question: What were the mash temps used when those old brewing text references cited mash pH? Neither of us know. I can only imagine that it would be in the saccharification range (140s to 150s F). Given that, the variation in pH within that range would be relatively small even if you assume the difference in room temp and mash temp pH was 0.35 units. (say 80F difference is to 0.35 units as 10F difference is to about 0.04 units). Pretty small.
--- End quote ---
--- Quote from: mabrungard on September 27, 2011, 01:40:12 PM ---Driving the mash pH down does increase the fermentability of the wort. That acid malt addition probably was the culprit. A couple tenths lower pH can have a substantial effect on fermentability.
The 5.3 pH measured is at the lower end of where I prefer the mash to go. I have had mashes at 5.2 and can assure you that the result was substandard for me...far too attenuated (the malt character was gone) and I could pick up a hint of sourness in the flavor profile. Aim for 5.4 in your mash in most cases and you can bump that up a tenth if reduced fermentability is desirable.
In my opinion, mash pH may be one of the final frontiers for tuning wort and beer performance. Bru'n Water is the tool to use for figuring out that tuning adjustment.
--- End quote ---
Pretty small, but pretty significant nonetheless?
beer_crafter:
great tips y'all!
gandelf:
Thanks once again for the info Martin. I purchased a fancy Milwaukee temp compensating pH
meter a couple of years ago. I called a Milwaukee tech to confirm the best procedure for calibrating
the new meter. The tech stated the same info as in Martins recommendation. He also included
this:
"To insure pH electrode longevity, insure test sample temperature is 60 to 80 F.
pH electrode condition test:
1. Use Windex blue (11.2 factory fresh pH) as a test sample, at least 2” deep.
2. Immerse pH electrode in Windex and note how fast a stable 10 pH plus is determined.
New pH electrode, stable reading is almost instantaneous.
Old ph electrode, stable reading takes 2 or 3 seconds.
Standard pH electrode life expectancy is one year.
Write replacement date with fine point Sharpie on pH electrode body."
punatic:
--- Quote from: gandelf on October 24, 2011, 04:05:54 PM --- New pH electrode, stable reading is almost instantaneous.
Old ph electrode, stable reading takes 2 or 3 seconds.
Standard pH electrode life expectancy is one year.
--- End quote ---
I think you were talking to a salesman. pH probes can and do last much longer than 1 year with proper care and maintenance.
Instantaneous and 2 - 3 second readings depend on your meter. I have a pH meter that allows you to select how long to measure and how many readings are averaged into the locked in value for the pH of the sample.
If you notice that your readings are taking longer to stabilize than they did when the probe was new, soak the probe overnight in a mild citric acid solution to remove scale that has formed on the probe's electrodes. You can buy citric acid in crystalline form at your LHSS.
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