[HopDen]

Is it normal for the wort pH to be higher than the mash pH? I brewed a Kolsch and hit a mash pH of 5.31, when I tested the wort pH it was 5.46. I'm using a meter and it has been calibrated.

[Bob357]

Sure. The grains, especially darker varieties, will lower the pH of the mash. That's why you generally don't check until the mash has stabilized.

[WhiteHausBrews]

Yeah that's normal for the pH to raise slightly, usually not going much past 5.4/5. Once fermentation kicks off you'll find it starts dropping again.

[mabrungard]

If the mash was truly homogenous, then it would be untypical for the pH of the mash wort to be lower than the kettle wort. Is it possible that the mash wasn't homogenous...not well mixed and recirculated?

[dmtaylor]

Possible temperature effect?  At what temperature exactly was each measurement made?  Temperature has a significant impact on pH readings.

[KellerBrauer]

I agree with Mr. Brungard.  With a Kolsch, Im guessing, you needed to add chemicals to lower the pH - Lactic Acid, perhaps?  If it was not well blended, or if you didn’t allow the grains enough time before testing, it may have caused an erroneous reading.  I test my mash pH many times (3-5) and I mix the heck out of it before and after testing and before and after adding Acid.  I believe the wort pH should be the same as the mash pH.

[HopDen]

Well, I believe I mixed the grains well enough. I underlet the strike water until the full amount is brought over from the HLT then mix. I have a HERMS so I do recirculate the mash.

[HopDen]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

[dmtaylor]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

WARNING!  WARNING!  NO, it does NOT truly "adjust for temperature".  You absolutely must be cognizant of temperature effects.  Forget anything about "Automatic Temperature Correction".  It's not what you think it is.  Common misconception.  Take note!

[HopDen]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

WARNING!  WARNING!  NO, it does NOT truly "adjust for temperature".  You absolutely must be cognizant of temperature effects.  Forget anything about "Automatic Temperature Correction".  It's not what you think it is.  Common misconception.  Take note!

Lets get down to brass tacts here and learn me something!!
So,auto correct aside, how do I adjust for temp manually? Slide rule?

[brewinhard]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

WARNING!  WARNING!  NO, it does NOT truly "adjust for temperature".  You absolutely must be cognizant of temperature effects.  Forget anything about "Automatic Temperature Correction".  It's not what you think it is.  Common misconception.  Take note!

Lets get down to brass tacts here and learn me something!!
So,auto correct aside, how do I adjust for temp manually? Slide rule?

My pH meter (milwaukee 101) came with a reference sheet indicating temps of the wort and appropriate buffer pH readings (for both 4 and 7 solutions). When calibrating, I take the temps of the solutions then turn the dial on my meter to match the solution temps prior to calibrating. I then make sure that my wort temp is the same as the reading temperature that I calibrated the pH meter with when I take my mash pH readings.

[dmtaylor]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

WARNING!  WARNING!  NO, it does NOT truly "adjust for temperature".  You absolutely must be cognizant of temperature effects.  Forget anything about "Automatic Temperature Correction".  It's not what you think it is.  Common misconception.  Take note!

Lets get down to brass tacts here and learn me something!!
So,auto correct aside, how do I adjust for temp manually? Slide rule?

At mash temperatures of approximately 150 F, add 0.25 to the pH.  At room temperature, add nothing.  If in between, pick a number in between.

The 0.25 number is not baloney either; it is based on a lot of real data from Kai Troester, Gordon Strong, John Palmer, Ashton Lewis, and..... me. 

My pH meter (milwaukee 101) came with a reference sheet indicating temps of the wort and appropriate buffer pH readings (for both 4 and 7 solutions). When calibrating, I take the temps of the solutions then turn the dial on my meter to match the solution temps prior to calibrating. I then make sure that my wort temp is the same as the reading temperature that I calibrated the pH meter with when I take my mash pH readings.

I do something similar to that too.  Good point.

[Kirk]

I think the difference is so small and wonder if it really makes a discernible difference. As stated in o.p I do use a meter and it is calibrated and adjusts for temperature.

WARNING!  WARNING!  NO, it does NOT truly "adjust for temperature".  You absolutely must be cognizant of temperature effects.  Forget anything about "Automatic Temperature Correction".  It's not what you think it is.  Common misconception.  Take note!

Lets get down to brass tacts here and learn me something!!
So,auto correct aside, how do I adjust for temp manually? Slide rule?

At mash temperatures of approximately 150 F, add 0.25 to the pH.  At room temperature, add nothing.  If in between, pick a number in between.

The 0.25 number is not baloney either; it is based on a lot of real data from Kai Troester, Gordon Strong, John Palmer, Ashton Lewis, and..... me. 

My pH meter (milwaukee 101) came with a reference sheet indicating temps of the wort and appropriate buffer pH readings (for both 4 and 7 solutions). When calibrating, I take the temps of the solutions then turn the dial on my meter to match the solution temps prior to calibrating. I then make sure that my wort temp is the same as the reading temperature that I calibrated the pH meter with when I take my mash pH readings.

I do something similar to that too.  Good point.

I used to take measurements at Mash temp and apply a simple correction factor for what the reading "should be" at room temp (published material appears to reference room temp). This factor is around 0.2 or so as previously indicated by others in this thread.

However, now I find it almost as easy to take a sample and place it in ice water for a couple minutes. This cools it down to room temp quite fast, and removes the ambiguity from the measurement. Use a pipette or something to take the sample, set it in ice water and swirl it around. My pH meter also reads temperature, so it makes it a breeze to take the measurement.

Also - excessive heat is hard on the probe tips. Taking your measurements at room temp will lengthen the life of your probe/meter.