If my mash pH is 5.65 at room temperature and is thus corrected to a 5.3 pH at mash temperatures, does that mean my mash pH is 5.3 and therefore doesn’t need correcting? I’m doing an all Pilsner beer and not using any acid correction. Am I fine?
When referencing Mash PH, it’s almost always at room temperature that you should target and measure. having said that, 5.6 isn’t the end of the world. You should be fine.
Not almost always. Always. pH always refers to pH measured under standard reference conditions, or it is meaningless. In brewing that has always meant 20°C, and remember that if your meter has ATC, that only corrects for the function of the electrode, not the actual change in mash chemistry at different temperatures. You must still measure pH at room temperature.
So when one says you should have a mash pH of 5.2, for instance, they mean if you measure the mash at mash temperature you would get a 5.55 (with the 0.35 correction)?
The “0.35 correction” is really something of a homebrew myth, actually. pH will always measure lower at mash temp than the actual room temp pH, but there is no correction formula. The displacement is unique to each mash, depending on grist, water composition, time, temperature and other factors, and varies widely (from around 0.1 to 0.6.) The only way to know the mash pH is to measure it at room temperature.
I don’t know, what does Bru’n Water say? Anyway, there is a negligible difference between 20° and 25°C (or lower) as far as I know. (Temperature in whose room anyway? Mine’s pretty chilly this morning.) It’s as the temperature rises higher the displacement gets bigger.
Yes you are correct, one of those posts where you throw in the “almost” as a matter of habit, but yes, always at room temp. I use medicine cups for samples during mashing. they cool quickly and are the right size for my probe.
Always record your mash pH at room temperature, which for the OP is 5.65. That is indeed a bit high. I’ll bet the beer still turns out fine, but ideally should be adjusted down by salts or acid.
The correction between mash temp and room temp is 0.25, not 0.35. This has been confirmed by several including myself. I have measured mash pH at mash temp without ill effect, aiming for 5.4 at room temp and 5.15 at mash temp if measured there.
For those who mash single infusion about 150 F, see my response above. For those who step mash at 7 different temperatures, I don’t know what the pH is at different temps.
There is no universal correction factor even with specified temperature, because the composition of each mash makes it behave in its own way, it seems. Published experiments bear this out; just for starters see DeClerck ch. XII. Palmer and Kaminski promulgated a supposed correction formula that involved multiplying the difference between mash temperature and reference temperature by a constant and adding this to the apparent pH. I tried it countless times and found it was always wrong, usually by a significant margin, and in no consistent way. If someone seems to regularly see the same “correction,” say 0.35, 0.25, etc, I would suspect this is because they are regularly setting up similar conditions – liquor, grist, procedures, what have you. I would not want to suggest to a brewer that they can trust anyone else’s results; best to take an accurate measurement yourself under the correct conditions. Should you find you can establish your own rule of thumb, that’s fine.
It wasn’t a dig at you Dave. It’s just misleading and people will take that and run with it.
You have to think that if you don’t specify a single infusion temperature as you did above, people will just say, “So and so from such and such forum said the correction is actually 0.25 pH units.” That’s just simple human nature and it’s how myths and rumors get started and gain traction.
Do you though. That number is your number and it strikes me as valid for you. I wasn’t trying to force you to clarify, but it’s probably good that you did.
Not really what I meant when I said that but it does little to change the fact that ultimately, for those following best practices in pH measurement, the correlation between mash temp and room temp pH is an absolutely useless metric.
To the OP: All recommended pH values and pH optima are referenced to room temp. Measure at room temp and disregard all talk of measuring at mash temp. Measuring at mash temp is known to degrade measurement equipment and if you want longer life and reliability out of your meter, always chill before measuring.