Note: all pH measurements referenced in the below post are room temperature measurements.
In How to Brew, Palmer states that the goal is to hit a mash pH of between 5.4 and 5.8.
However, I’ve read a lot of posts on this forum where people state their target mash pH is 5.3. I’ve also read some posts where it has been posited that a mash pH higher than 5.6 can cause problems - regardless of the style of beer being brewed.
Has there been a recent shift in thought concerning optimal mash pH?
The short answer is there is no “optimal” mash pH.
Have you seen this: How pH affects brewing - German brewing and more
“A commonly accepted optimal range for mash pH is 5.2 - 5.7 with 5.5 being optimal for starch conversion activity but many authors report wort and beer quality benefits if the pH is lowered into the 5.2 - 5.4 range [Kunze, 2007][Narziss, 2005]. Kunze in particular lists the following benefits for a mash pH as low as 5.2. Since it is a good and fairly comprehensive list I cited it here. Some of these benefits listed will be explained in the following sections [Kunze, 2007]:”
I know a lot of people love John Palmer, but I think a lot of his advice is a bit off.
And they don’t always mention whether the mash pH was measured at room temperature or mash temperature.
The higher mash temperature can lower the pH by 0.3 pH. So 5.4 to 5.8 at room temperature is actually 5.1 to 5.5 at mash temperature.
sierra nevada mashes at 5.2 from what i’ve read. i’ll trust that they’ve done their homework on outcomes from hitting that number.
That makes sense. Their brewhouse is German and Kunze says there are a lot of benefits to mashing at 5.2.
Is this at mash temp? That would be 5.4-5.5 at room temp, which is pretty typical. I think someone (Denny?) said they measure all pH at the intended use temperature when he was talking about their water adjustments. Please correct me if I made that up 
At any rate, the range for conversion is actually pretty large, so I don’t think John is wrong. In practice, I think most brewers aim for the lower end of that range for other benefits.
I don’t recall saying that, but I cool to room temp (70-75) for measuring.
Looks like it was Gordon who said it. Close enough (sorry Gordon!).
http://www.homebrewersassociation.org/forum/index.php?topic=12253.msg161096#msg161096
From what I have read, all the breweries take their readings at room temp in the lab.
Dave
I recently had a discussion on mash pH with alot of heavy hitters weighing in. All said that you measure mash pH at room temp. It is what the testing equipment (strips, probes)are calibrated for. The specific temperature might vary a few degrees based on the manufacturer, but still around what we all would consider room temp.
I also recall saying that which end of the optimal range your mash pH falls in will result in a slightly different flavor profile. For me that is getting pretty granular so I just try to hit 5.2-5.7 at room temp.
I agree that you should cool your sample for the sake of your equipment. Unfortunately, it doesn’t seem to be a reasonable assumption that all breweries and texts quote their readings at room temp. My impression of what Gordon said was the Sierra Nevada was either measuring or correcting their reading to be represented at mash temp. Perhaps he can add some more insight to this.
Sierra Nevada did when I was there.
For a while now I’m trying to find a commercial brewing equipment manufacturer that offers in-line pH probes. The description for that probe may show how to convert between between mash and room temp measurements.
High temp in-line pH probes do seem to exist for food processing.
Kai
I don’t know how much use this will be, but here’s the pH testing setup at Sierra Nevada’s pilot brewery…
At least in my mind, and I have thought about this a lot) there is little doubt that pH measurements at room temp are standard practice. I’m curious though, if there are brewers in the industry that also have the ability to measure pH at process temp and how they correlate this with room temp pH measurements taken in the lab.
Kai
Cool photo. Does that say 52.5 C?
52.5 degree Celsius = 126.5 degree Fahrenheit
So maybe they aren’t waiting to cool it completely…
So remind me again why we measure at room temp and then do a conversion? Are pH meters significantly off at any higher or lower than room temp?
Hi all,
I have used the pH meter Denny posted, and I can say with some certainty that the probe they are using is VERY sensitive and must be almost constantly in a buffer solution at room temp except when the probe is in the beer (and the beer must be at room temp also).
I have used probes that are designed to be much more robust and could measure solutions at high temps, but the readings were only for information (to make sure we were on track with pharmaceutical batch production). When needed we would always cool a sample and take a reading at room temp for an actual in-process check. I seem to remember the degree of error increasing quite a bit once a sampe was more than a few degrees above room temp.
Hope that helps.
It sat there for quite a while and I’m pretty sure that it ended up at room temp. Mike K., you out there? Do you recall?
I know this information is specific to my probe but thought it might prove useful in regards to this thread.
"The GK733526B electrode is rated for use from 0 - 100 °C. That does not mean is should be continuously used at that kind of elevated temperature, but if you are doing grab samples, it should not be a problem.
Accuracy should not be affected if you are using it at an elevated temperature, but you should be using a temperature sensor on your pH meter for accuracy at those temperatures, and yes, for most accuracy, you should also have your calibration standards at 68 °C when calibrating.
Also, do not expect to see the same pH readings at 68C as you do at 25C. I am not sure how your sample will respond to that kind of temperature change, but as an example, the pH 4 calibration buffer that reads 4.005 at 25C will read 4.116 at 70C; the pH 7 buffer that reads 7.000 at 25C will read 6.982 at 70C.
If you have any other questions, please let me know.
Thank you.
Sincerely,
Tim Schmitt
Technical Support
Hach Company
